As mentioned in the other answer, the first thing that could be tried is adjusting the B-screw.  This adjustment will vary the gap between the jockey wheel and cassette. Clockwise rotation of the B-screw moves the jockey wheel away from the cassette, widening the gap between them.  Conversely, loosening the B-screw counterclockwise, will move the jockey wheel close to the cassette.  Proper position for setting the B-screw is when chain is on small chainwheel and large rear cog. Measuring from tooth tip to tooth tip there should be a 5-6 mm gap between jockey wheel and large cassette cog. An Allen key of 5mm should just squeeze through the gap is how I determine my adjustment. Even though your shifting seems unaffected, the jockey wheel should not interfere or touch the cassette in any way.


The most important thing to consider is your frame, not your crankset. You can make almost any crankset work for a singlespeed.

Your frame needs to have horizontal dropouts so that you can tension the chain. Or you can use a chain tensioner, which is essentially the spring part of a rear derailleur. Looks like the San Jose has horizontal drops, so you're fine.

As for the crank, all you really need to worry about is maintaining chainline, which means that your rear and front cogs are lined up. You can affect this on the front by moving your one chainring into the large/small position on the crank, or using washers to move your chainring slightly over. EDIT: Now the overall position of the crank will be affected by the length of the bottom bracket spindle, as this will also affect the chainline. In practice, I wouldn't worry about this too much, again, because you can slightly adjust the position of the chainring after the fact.

In the rear, you can shift your hub axle slightly if you really need to, but you should focus on getting the front right before you resort to this. Note that this only applies to freewheel style hubs. If you are going to run cassette hubs for a single speed, then you can sometimes run spacers to get the rear cog exactly where you want it. There are some less other common configurations that I won't deal with here as well.

The other thing to keep in mind is that chains are meant to bend somewhat, as seen in normal use on a geared bike, and so a small offset angle is not going to hurt you.


Depending on your brakes and their design, you may not want the rotor centered.

If both pads move when the lever is squeezed, then center position is correct.  However, if you have one fixed pad and one pad that moves you want the rotor to be as close as possible to the fixed pad (without touching/rubbing) so that it bends the least when the one moving piston is engaged.

Most brake manufacturers design their brake calipers with slotted grooves so that the brake unit can be adjusted.  Some Magura breaks are an exception to this and require you to adjust the rotor with spacers.  However, for most disc brakes, if you have the proper adapter and true rotor, these slots should be all you need to adjust the unit properly.


What did people ride for cold weather cycling "back in the day?" (Is it cheap?)

Wool, wool, and wool. Wool undergarments. Wool over garments. (Maybe tweed as well.) Wool is a amazing material. It tends to perform better than synthetics (although the gap is closing) for keeping you warm when it is wet and cold outside.

On descents people also used to just either tough it out or did life hacks such as putting newspaper down the front of the jersey rather than rely on fancy rain shells.

Now here is the caveat about wool and the old world approach. Real wool garments are often much more expensive than equivalent synthetic garments. So from this perspective synthetics are a much better choice than killer cotton if you cannot afford wool. Synthetics also tend to wear a bit harder and typically don't need to be hand washed, so wool is more care. You typically only had a few garments which you washed by hand at night before the next day of riding. You also had to learn how to darn wool, so you could fix damage that can happen to wool over time.

Synthetics dominate today because of the cost, reduced care and good enough performance.


What is the size of my seatpost clamp nut?

This looks like 16 threads per inch, which would indicate a 3/8 inch bolt if you are using SAE sizing.  It would take a 9/16 inch wrench.  If you use a box wrench (or even an open end) you are much less likely to round off the nut than if you use an adjustable wrench.  It could be 10mm, which would have a thread pitch of 1.5 mm and looks like it would take a 17mm wrench.
The threads on your bolt look fine, so take it to the store and test fit the new nut to see if it matches.
Note that your nut has a captive washer on it.  If you buy a standard hex nut you should use a washer behind it.  There may not be enough flat space for a standard washer.  Nuts like this are fairly common, but not as common as the vanilla hex nut variety.


Rollers for long-wheelbase/mountain bikes

Rollers (and trainers in general) chewing up tires isn't uncommon as indicated in this answer on a related question:

https://bicycles.stackexchange.com/a/10748/4239

As indicated, just use cheap tires for your rollers. I ride them in the winter and I've never really noticed that the rollers chew up the tires much faster than the the snow, ice, salt, and cinders on the roads do.

As far as the wheelbase goes, you can  find the wheelbase range for rollers in the specs on some sites. You might have to dig around though. For example, nashbar.com listed the specs for these rollers even though the manufacturer's page did not. I'm sure it could be found in the product manual as well, but I didn't dig that deeply.

Also, almost any sort of tread pattern on your tires will make the rollers very loud. And of course, the bigger the knobs, the louder it will be. If you're going to put a mountain bike on them, you'll definitely want slicks.


How do I take apart the axle and freehub on this bike

They both look pretty standard to me. Normally you remove the lock nut and cones from one side. The bearings should be visible and fall out (careful to catch them all.). The axle should then just push through to the other side. If you can see the bearings (or they fell out), a gentle tap, with a light hammer may be needed (although i cannot imagine why) to dislodge the axle.

With the rear wheel, remove the lock ring and cone from the left side (non-drive) and push the axle through (again, watch the bearings).


This could be pretty much anything, you might want to find a specialist in lugworks. Many Italian frame makers had very unique lugging to determine their bikes from the rest. I used to know a few by heart back in the days when I was restoring old racers for Single Speed Co but I'm afraid that skill has fallen back now. Having unique lugs was especially important on older bikes.
I can't see on the photos what is happening between rear dropouts, it could be an old track frame but some older bikes never had the horizontal dropouts so it could just be an old frame designed as a single speed bike. It definitely looks older than 80's and even 70's are still questionable.

How is the weight on this?


What does chain worn indicators 75% mean?

The .75 is not 75% worn per se.
A chain checker measures chain stretch.
Chain stretch is an indicator or wear-and-tear.
Parts of a drive train wear at different rates. For instance the teeth of the chainset will show wear when they become "shark-finned". But this could be long after the point at which you should replace a worn chain.
If you persist in using a worn chain - though you may not notice anything detrimental - but when the chain eventually gives up - and you put a new chain on - you may find it skipping under load through the gears. This requires replacement of chain-rings / cassettes.
An earlier replacement sought - would have prolonged the life of chain-rings / cassettes.

As for your last question - it is difficult to say - if you ask a manufacturer - they will say no difference. Personally, I think the wider chains lasted longer and are stronger than the narrower 10/11 speed chains of today.

Don't know of any exceptional single-speed chains ... just keep it well oiled and it will last longer.


GPS may be accurate +/- 15 meteres.
http://gpsinformation.net/main/altitude.htm

If you have a GPS device with barometric measurement - then this can improve.

Should you be worried? If you're using it for cycling then probably not - it is only an indicative figure of metres gained or lost.

If you're trying to land a plane - then yes. :)


It will work adequately on your 6 speed rear cluster.  Its basically 8 speed chain which is identical width to 7 speed chain, and its "good enough" for 6 speed.

Curiously, on a supplier's website for HG40  I notice this line:

  Shimano Altus HG40 6-7-8 Speed Chain
  7.3mm chain width, optimised for 7- and 8-speed HG drivetrains

6 speed is 0.5mm wider but given the tolerances of the day, that should work adequately.  You have to move the derailleurs a tiny bit further to make a shift if its friction shifting.  The FD cage may need to be closed up slightly.

Finding 5/6 speed chain will be interesting - even KMC's own chain checker only lists 8 speed chain as the best option.  http://www.kmcchain.eu/chain-road_cross-multispeed-5_speed

Apparently "clarks CL20" is 5/6 speed chain and may be found at various on-line suppliers.

6 speed is a comparatively old standard and is way less common now, so not worth printing on the packaging?

As per https://en.wikipedia.org/wiki/Bicycle_chain#Width

  6 speed – 7.8 mm (5⁄16 in) (all brands)
  7 speed – 7.3 mm (9⁄32 in) (Shimano HG), 7.1 mm (9⁄32 in) (SRAM, Shimano IG)
  8 speed – 7.3 mm (9⁄32 in) (Shimano HG), 7.1 mm (9⁄32 in) (SRAM, Shimano IG)


Is there a way to know what size of smallest chainring will be compatible with a given frame?

The Devinci Milano uses a standard 68mm English threaded bottom bracket shell.  This should be compatible with most road cranksets, so long as you replace the bottom bracket as well.


Why are my brake pads completely eroding after one week

It sounds like you are buying unusually quickly wearing pads. 900 miles is a short distance from a set of brake pads, but 5-6 sets over 400 miles is really excessive.

Personally, I have had very good mileage and all weather performance with Kool Stop Salmon pads. The original pads from Shimano are not particularly good, but not the worst either. There are some other brands that have good reputation, but I haven't tried all of them.


upgrading components on a Brava late 80 early 90

So many changes - unless you're particularly attached to that bike, consider a new one with the components you want.

Otherwise your shopping list is new shifters, new cassette/freewheel, new chain.

You probably need to check the new chain will run on the existing front chainrings, else they need replacing.
If the new cassette/freewheel fits the existing wheel then that's good, otherwise its a new hub, possibly new spokes and a wheel rebuild, or a complete replacement wheel.

The rear deraileruerueuruer is probably OK, they are not indexed and don't really care.   However if the wire pull is different between gears, this needs changing too.

The front one is likely OK, unless you want the same type of shifter lever front and rear.

Just remember, a new bike will be lighter and have a warranty, and you could choose one with disk brakes if that appeals.


Try Old Roads. I don't know how accurate this information is though.

As 'user973810' suggested, try Sheldon Brown's Vintage bike pricing guide  as another reference.  Again, you may question the accuracy of the data.

 Vintage Trek has some original price lists and a lot of information on old trek bikes.  If you happened to be looking for information on treks, then check there as a guide for info about the bike.

If you had a schwinn, I'd recommend checking (maybe even emailing) Bicycle Heaven, a shop and museum, they have a massive collection of vintage schwinn and other bikes. Here's another good guide on finding prices for old schwinn bikes at Schwinn Cruisers. Their site has a lot of info about old schwinn models.

Check recent ebay auctions and see if there are any completed listings for that bike. Try using "completed items only" checkbox. It may still be hard to find results for some bikes. You may be able to compare prices versus their inventory.

Use something like  searchtempest  to search multiple craigslist sites to see if there were any postings for that style bike anywhere. These can vary somewhat wildly from actual value, both above and below, depending on the seller.


How much does the price of a new bicycle drop a year after buying it?

I would use bicycle blue book as a way to figure out the change in value of the bike.  They have a system to estimate the resale value of used bikes.  Your bikes condition at the end of the year will matter so keep it clean and lubed.


Mechanical cable-actuated disc brakes started working really badly

My guess would be the cable is old. The inner cable begins to seize or bind with the outer cable. This could be caused by corrosion caused by water ingress over time or dirt ingress over time.

The binding basically causes more friction along the line of the cable - eventually preventing a smooth return to the "Off" position on the brake lever.

You can do a "bodge" and that would be to squirt something like WD40 down the cable line to free it up. But this is only a temporary fix.
The proper fix is to install some quality pre-lubed cables which are also weather sealed.

Incidentally, pads contaminated with oil can be cleaned by removing the pads and heating the pads over a flame to burn off the oil.


How to attach and mount wheels onto a cargo trailer?

lantius is almost right IMO.

use a standard bicycle wheel with a thin through axle, supported from both sides. It's possible to make a really simple trailer this way that will carry quite a lot. The disadvantage is that it's wider than a single sided mount for the same track width (how far apart the contact patches are). Small wheels off kids bikes are often available cheaply or free, and will usually carry 50-100kg each for a few hundred km before they fall apart (come fail immediately, but they're free so don't worry about that).
use a single sided wheelchair hub. They are light and designed so the wheels are easily removable, which is handy for a trailer that will be packed away often. But they will not carry much weight (20-40kg each) because bike trailers get used much harder than wheelchairs do. They're also somewhat expensive unless you can find a stock of wrecked wheelchairs.
use a thick axle with single sided support. MTB hubs come in 15mm (Shimano) and 20mm through axle variants, and a 20mm steel bolt the right length is easy to weld onto the side of a trailer and will hold more weight than even a really well built wheel (you could even drill a 10mm hole through it to save weight. But it does need to be supported well as there is a lot of force on it). I have a trailer built that way that regularly takes 120kg or more without complaint. Unfortunately the build page for it is unfinished even though the trailer is ~3 years old. These 20" wheels are expensive($US135 each) because you will not find them second hand but they work. TriSled use those ones on their load bikes rated to over 100kg/wheel.

You will need to use small wheels on a two wheel trailer (or build your own hubs) because the side forces in corners are more than a 26" or bigger wheel can cope with. With a solid build and care when cornering a 24" wheel can work, but a 16" or 20" wheel will just work. If you build your own hubs with 100mm or more between flanges you could use bigger wheels, but you end up with a very wide wheel (you just added 100mm to the width of the trailer without adding to the load space).

Finally, you must look at Richard Guy Briggs' organ trailer. It's a bike trailer that carries a Hammond organ and player.


You probably need a new cassette/freewheel. A new chain on a worn cassette will jump (especially on the harder gears).

The harder gears have two things going against them.
Less points of contact to share the load.
Less points of contact so they tend to be worn the most.

If you have front derailleur then using the bigger ring there will let you use bigger cogs in the rear.  If I can be in 3 or higher in the rear on the big ring up front then I use the big ring up front to keep miles off the smaller cogs in back.


I did a cheap paint job once. I'm mechanically inclined, so for me it was not a problem to disassemble the bike. Used 1000 grit sand paper to remove the gloss (opening pore) from the paint and then washed the frame with kitchen soap. Let air dry without touching it too much.
With clean hands, tape any piece I didn't wanted covered, because I didn't completely undo the bike. At this point, One complete can of spray paint was enough. I finished the job with stickers that I had printed myself at home.
Sanding is laborious, but completely necessary. Opening pore in the paint creates a better surface for the new paint to adhere to. Washing is crucial to remove grease and dust, both of them prevent paint adhesion. For a strict budget project it is better to conserve original paint because it is already well adhered to the frame and it works great as a base coat. It is easier for new paint to adhere to porous, clean paint than to bare metal. Do not sand too much, since factory paint is really thin, and some times you wont find a different color base to guide. Use a flashlight (torch) to check if you removed gloss and that's enough.
Masking any part that should not be painted is highly advisable. For a start, paint should not get into any pivot, bearing, axle. But second, correctly masking the bike before painting gives the final work a better look (it can be so good it doesn't look cheap nor even home made). I recommend removing wheels, cables, derailleurs, handlebar, stem and crank set. Bottom bracket can be masked. Also mask fork bearings (headset) and seatpost. Leaving the seatpost is advisable to have a "handle" so you can move the frame while painting so you don't damage the paint job.)
The trick to paint a bike (or anything) is to use several light coats instead of a single thick coat. Start moving the can before you press the nozzle and use quick, consistent movements, continue moving the can after you release the nozzle. If you watch any car restoration shows or similar, you'd see that they do this with their paint guns.
The first coat must be so light that the original color easily shows through. You should be able to give the frame and fork 3 coats from a single paint can. Let dry each coat before applying the next. The can label should tell the drying time.
It is absolutely necessary to let completely dry the paint before reassembling the bike because the paint may be "touch dry" but still not completely set. If you handle the frame at this time you will smear the paint or cause finger print marks on it.
Finally, some stickers can help to make the bike look better. In my case I used inkjet printer on plain paper, then I used clean vinyl paper to cover and adhere it to the bike. How ever It may be cheap enough to have them professionally printed. At this time (2014) in my country they charge around 1 euro to print a sticker the size of a letter size (A4) sheet of paper.
For reference, in my country (Honduras) a can of paint can cost the equivalent from 2 to 4 Euros, a sheet of sandpaper costs cents, and a roll of masking tape is like half an Euro. So the hole project is around 5 to 7 euro, plus your workmanship.
I really advise you on being patient and not paint several parts with the same paint and not letting over spray fall on anything not intended to be painted, because that usually gives a bad, cheap look, and you may end up liking the bike even less than you like it now.


Dedicated 1x systems do have some specific features:

11 or 12 speeds
Derailleur able to handle a super ratio cassette (at least 11-40)
Narrow-wide chainring
Clutch system on the
derailleur.

You can definitely cobble together parts to make a 1x10 (or 1x9) system. A Vee crank will most likely be fine. 12-32 cassette is reasonable (11-32 would be OK too). A 7 speed derailleur won't work.

You'll want to consider your overall gear ratio spread vs size of the ratio steps. Trying to run a cassette with a too-wide range means you'll have big jumps between gears, and requires a derailleur that than handle the largest sprocket size. If you settle for a narrower range cassette (sacrificing either high or low ratios, depending on what size chainring you select) gives you more derailleur choices. A narrower range cassette also means the derailleur has to deal with less slack chain when on the small sprockets and hence less chain slap.

The rear derailleur does not care what crank you use, or the chainring size. Just select a crank that fits your bike, gets the correct chain-line and has a bolt pattern and diameter that will take a chainring of the size you want. Narrow-wide chainrings are a good idea for better chain retention.

You need a derailleur compatible with a 10 speed shifter. For Shimano 1x10 you will have to use a 10 speed derailleur because Shimano 10 and 11 speed MTB groups use a different derailleur actuation ratio than 9, 8 and 7 speed groups.  The derailleur also needs to be able to handle the largest cassette sprocket


Back wheel lock up, when got off wheel would move side to side

If the wheel wobbles in the frame (and the QR or through axle is tight), or with the wheel out you can wobble the axle in the hub: at least one of the bearings has a problem, or perhaps the axle broke or the hub shell has failed. If you have a serviceable cup and cone bearing hub, one of the cones may simply have come loose.

The way forward depends on what kind of hub you have. Without more info on the specifics of you hub we can't provide further advice.


How to install a cartridge bottom bracket (threaded) in threadless shell?

If you want to be able to install any ISO threaded BB, the way to do that is use a press-in adapter.

They have the disadvantage of not necessarily solving the creaking issues that might have gotten you to this point in the first place.

If you just want a simple way to run common 24mm or 24mm/22mm cranks, there are adapters that plug in to an existing PF30 or BB30 for that.

If the shell is metal and you want to run square taper, you can in theory get it cut to T47 and run a Phil Wood BB in it with their T47 cups. Despite being insane, this is the solution most likely to result in zero creak issues.


What to substitute a lost pedal dust cap with?

By the time you have driven around town looking for a suitable sized dust cap, new Pedals might even work out cheaper.
One option could be use the pedal itself as a mold to make one from a silicon sealer.
Local hardware store will have a range of plastic end caps for things like curtain rods chair legs along with other and general hardware purposes.  You might find a suitable sized item there. Its the kind of thing an LBS might have in a box of bits.


Bike pulses while applying the front brake. I'm unsure what the cause is

Measure the rim in a more accurate way for starters. Even 0.1mm can cause a change in the braking power.
Also, with the bike resting on its handles and seat, flipped over, ask someone to lightly hold down the front brake while you slowly turn the wheel and figure out exactly where the trouble spot is and how big it is. If there is no visible difference, and you don't have the means to measure the rim more accurately, then it probably is the width of the rim being uneven. On the other hand if you find that it does not occur at the same spot every time, maybe the problem is elsewhere.
If you can, see if the width of the rim changes radially, fatter near the tire and thinner near the spokes. If the difference in this width isn't constant, it could be causing the problem


Which kind of electric-assist bike would be appropriate?

The choice of whether to ride an electric-assist bike or regular bike involves a lot of different factors, including just your own personal wants and desires. E-bikes add an extra dimension to the riding that can make it more enjoyable for some, especially those that don't already have an affinity for bike riding to start with.

So any answer will necessarily involve a healthy dose of opinion, and you'll have to see which of those opinions seem to mirror your own approach to riding best.

That said, it's worth focusing on your specific scenario, as prep for your broader research into what electric bike specifically would work best for you…

IMHO an electric bike is most useful if you have one of a few different goals as a priority:

Reducing time riding. Even on a flat, an electric bike will let an average cyclist go faster. Note however that an experienced, fit cyclist can easily ride at the same pace on flat terrain as a regular pedal-assist bike will operate (in the US, e-bikes treated as regular bikes are limited to 20 mph for assist, while outside the US, I believe the limit is 25 kph…faster than that, and the bikes become subject to at least some of the motor vehicle regulations, including prohibitions for use on bike/shared-use trails).
Reduced effort. For some, this is as much about practicality as it is laziness. While an experienced, fit cyclist can maintain 20 mph on a flat, this still requires effort, which at the very least will likely involve sweating, and may call for specific clothing. With an e-bike, one can ride at higher speeds with relatively little effort, in street clothes and arrive at your destination ready to work, play, whatever.
Flattening the hills. This is a corollary to the previous two points. In some locales, the riding is already very flat and comfortable, speed is not important (and may not be even possible, depending on congestion on the bike trails), and an e-bike would be superfluous. But in a hilly place, the presence of hills might significantly slow you down, and using an e-bike might turn an impractical ride (due to time or effort constraints) into a practical one.

As a case-in-point: I currently commute using an electric bike. I have for decades used a regular bike for commuting, but my longest ride had been about 10 miles, and for much of that time I was riding less than 5 miles each way. Even with moderate hills, this was fine for my level of fitness and time availability. But my commute has recently increased to about 25 miles, over very steep hills, amounting to about 1800 feet of vertical gain over the ride. Without an electric bike, this would probably be about 2.5 hours of riding each way, but with the electric bike, it's only 1.5 hours.

In your own example, the distance is clearly within the range I found comfortable on a regular bike, even with hills. So I'll point out the first obvious fact:

While you may be getting tired now, you will find that over time, it gets easier. Probably a lot easier depending on your current fitness level. This depends a bit on how hilly it is, but even with hills you'll find you're able to climb them faster, or with less effort, or both. If you keep the travel time constant, you'll expend less effort as you get stronger. If you are willing to expend the same amount of perceived effort as you get stronger, you'll find that the ride goes more and more quickly. The bulk of the gains will come early in the process, and with such a short ride, you may not find much improvement after that, but the ride will stop feeling like a chore regardless.

In other words, don't judge the ride by how you feel now. I have found that a short 20-minute ride home after work is just what I need to unwind. One thing I've always valued about biking is that it's one of the few places I get any real exercise, and so I don't mind spending the time doing it. I quite enjoy it,  actually. (That said, if your job involves a lot of heavy lifting or other exhausting work all day, maybe you'll never find biking home to be something you look forward to.)

On a ride of the length you're proposing, an electric bike is going to be more about transportation than fitness. Even without an electric motor, it's just barely long enough to improve your fitness, but with an electric motor, the ride will be shortened so much that even the aerobic benefit will be minimal, and you probably won't get much if any strength benefit.

If you do decide to get an electric bike, all of the information that's already out there should be all you need. That is, there are a myriad of choices, and most of them relate more to how the bike feels to you than the ride itself. Any electric bike you find would probably work fine on that commute.

That said…I did wind up forming my own opinions of electric bike configurations before I bought mine, through lots of test rides, so I'll share those:

Most important: I really didn't like the bikes that didn't use torque sensors to govern the motor. Instead, they use pedal cadence sensors, and the motors are generally just "on" or "off". You can get used to that scheme, but I found that it made the bike seem more like an uncoordinated partner than part of the team. The motor would kick in hard immediately, instead of moderating its assist to match my pedal stroke, and it wasn't possible to smoothly adjust my speed with pedal force, because if I kept pedaling at all, the motor kept at its set boost. This gave the impression of the motor actually working harder as I pedaled more lightly and vice a versa, which is IMHO the opposite of what you want.So I strongly recommend considering only bikes that use a torque sensor to control the assist level.
The other big configuration choice to look at is a hub-mounted motor vs a mid-drive motor. The former drives the wheel directly, the latter drives via the pedal crank. This is largely a subjective choice, partly driven by economics (the latter are generally more expensive). There are pros and cons to each, covered adequately by any number of other resources. The biggest differences come down to weight distribution (hub drive puts the weight rear-ward, which can affect bike handling more) and gearing (mid-drive takes advantage of the bike's gearing, and so can provide more torque over a wider range). IMHO, the weight distribution is the more important of these two, but this may only be an issue if you also tend to ride with a rear rack loaded down with gear (I do, but many people won't), and is in any case mitigated by the fact that the electric bikes tend to be significantly heavier than a regular bike, so the center of gravity (balance) of the bike doesn't actually shift that far rearward even with a heavy motor on the hub.

Other options mostly involve things like where the battery is mounted (again, rear-mounted batteries mess with the bike balance in ways that frame-mounted batteries don't), how big the battery is, whether it can be charged on or off the bike (but your short ride means this is probably not that important), manufacturer (I found that Brose, Yamaha, and Bosch systems all seemed to work better than the other manufacturers I found and tried, but this is far from an objective, educated observation), how much capacity the battery has (again, your short ride means that pretty much any e-bike should suffice), and of course all the other components on the bike.

Regarding components, mainly I mean the brand and quality level. But one other characteristic that could affect your choice is the drive-train. Specifically, internally-geared-hub vs derailleur (the former available only with mid-drive bikes, as far as I know), and if IGH, then whether the bike is belt-drive or chain-drive. I ride in all weather except heavy snow, so I opted for a belt-drive bike. But honestly, the best riding bike (in terms of just how the bike handled and fit me) I found was from Haibike, available only with a chain drive. It was really a difficult choice to make, but ultimately I knew I didn't want to spend all the extra time and mess dealing with cleaning the chain and gears after every ride in the rain.

If you only plan to ride in good weather, chain drive is great, costs significantly less, and is universally available (limiting yourself to belt drive means reducing the available options significantly).


Why is this guy blocking the rear wheel?

No reason at all.

NWD10 is a classic old school movie. You don't see purposeless skidding like that in today's  MTB movies nor do you see it in real life MTB riding. Kirt Voreis (the guy in that scene - legendary rider) is probably doing this for no reason, just for fun, or at least what used to be fun in these old times.


3000km is enough of a wear life for a singlespeed freewheel that I would say there's nothing necessarily wrong here.

One way to check wear is just looking at the side of the freewheel teeth that contacts the chain versus the side that doesn't. The more asymmetry, the more wear.

If you ride it like it is, it probably will break in and get quieter, but what's happening there is your chain's pitch elongating to "catch up" to the freewheel, which isn't necessarily a good thing.

I don't have experience with the Halo one but it sounds like it might be a little too boutiquey for its own good. The cheaper Shimano freewheels are pretty excellent at reliability, wear life, and not being too painful to replace when they do wear out.


You rim should be centered over your hub. If you are using the tool correctly, and the rim is not centered, it should be redished.

If you are not confident in your abilities and knowledge on the subject, get a second opinion from your LBS mechanic before you make changes to the wheel. Sometimes, those kind of changes are difficult to reverse.


Safe pressure is limited by rim and/or tire strength, not the inner tube itself (and maybe by its valve, but that's not this case).

My guess is that your tire is little too big (or damaged) and inner tube comes out through gap between tire and rim and eventually explodes.

Please provide picture of blown tube ;-)


Some things i would consider, some could possibly be grouped together. Perhaps others can add on with more answers.

Custom Class

Originality/Creativity
Function
*Can you actually ride it semi comfortably or is it just cool looking
*Can it do something normal bikes can't?
Use of colors or materials (could lump into creativity)
Wow factor
Overall theme

Vintage Class

Period correctness (50's era components on a 50's era cycle)
Original parts (as much as possible)
Cleanliness
Paint/Chrome quality (new or original)
Function (are all required parts present and in working order)

For your points system, decide on what things you would like to judge , using my list as an example you could give each a 20 point value, 5 topics totaling 100 points maximum - Highest score wins


Questions related to ease of mounting can be nebulous to answer, because usually much more than any other factor, what determines how difficult a tire is to mount is the tolerances of the rim and tire. The most difficult mounting situations occur when the bead seat diameter of the rim happens to run large, and the bead diameter of the tire runs small.
There are some known models to avoid if mounting ease is a priority, but there is no totally reliable way to buy a tire that's easy to mount, because tolerance problems can strike randomly. Light, supple tires  mount easier on average, but it's not a guarantee.
Some highly flat-protected tires are notorious for being difficult to mount. As pointed out in the comments, the Schwalbe Marathon Plus has become a poster child for this. The reason is that, especially in narrower sizes, the massive amount of casing armor makes it difficult to get the beads sunk in to the rim well so that the section of tire 180 degrees away can be pushed over the rim and seated. They're also stiff and can be hard to even wrangle the first bead on.
I think that as long as you have still have the ability to reinstall the tire when needed, using a bead jack if necessary, it makes more sense to just choose something tough enough for the roads you'll encounter and the loads you'll be carrying. Unless it's thorns/goatheads/cacti/etc you're worried about, the stuff that gives you flats in a lot of flat-prone areas can also damage or destroy tires. Undergunning it carries the risk of a tire getting sliced instead of simply punctured, which is the kind of damage that the overbuilt casings of proper touring tires are good at mitigating.
If you do want to have some insurance against punctures that won't make any difference in mounting difficulty, you could also use tubes with sealant in them. Sealant has downsides, but can work well in areas plagued by thorns and goatheads, and makes a little more sense in an event ride type context than day-in, day-out.


Use 105 crankset on 9x2 Sora equipped bike

A 2018 bike with have an R3000 Sora 9 speed groupset.  The problem here is that you have a 9 speed chain that probably won't shift well on an 11 speed crank.

As 10 and 11 (and now 12) speed systems were created, the cassette sprockets needed to be more closely spaced, which required the outside width of chains to be decreased. The distance between crank chainrings was also decreased to accommodate the narrow chains. The 105 crank will have the wrong spacing for the wider 9 speed chain.

A safer option would be to upgrade to a external bearing Hollowtech bottom bracket and a 2-piece Sora crank, or an equivalent 9 speed crank and BB from another brand such as FSA.


It's difficult to say without seeing photos of the road layout.  However, if the road itself continues round to the left, you should indicate right when you're leaving it.

In general, you should think about the topology of the road, rather than its geometry.  It doesn't matter that you're following a geometrically straight line; you're still leaving the road for a separate carriageway, and you need to signal this intention.

The default assumption for someone crossing the road is that you'll continue along the carriageway you're already on.

This said, of course, common sense should always prevail!  Never do anything that feels dangerous (for you or for someone else).


Asymmetrical rims raise the weaker side tension and reduce the bracing angle disparity on wheels where the hub has a different center-to-flange distance on each side, as long as the amount of offset at the rim in question brings the dish closer to center than the offset at the hub moves it away from center.
SON28 disc hubs have smaller and closer to symmetrical center to flange numbers than most disc hubs. As you can see in the numbers from Schmidt's site below, the difference in center to flange is only 2.5mm for 6-bolt and 2mm for centerlock.

Therefore, you have to be careful with the golf-ball type generator hubs about not running into the mostly fringe situation of an offset rim doing more harm than good. You (or at least I) really need to run the numbers to figure out if it's beneficial. We'll use a WTB 29" Asym I29 with its 4.5mm of offset to demonstrate, with the KOM Light to compare with. Being able to do this easily is one of the reasons the nerdier spoke calculators are superior. I will use SpoCalc here.
6-bolt SON28 with WTB Asym I29 29":

6-bolt SON28 with WTB KOM Light I29 29":

Centerlock SON28 with WTB Asym I29 29":

Centerlock SON28 with WTB KOM Light I29 29":

130%-ish is further away from 100% than 91%-ish, and the bracing angles are way less disparate on the KOM. So in none of these example cases would 4.5mm offset be beneficial. It would be all downside. You'll need to do the math yourself for the parts you're using, but among contemporary mountain asymmetrical rims this is probably about what you'll see with the SON28 in particular.


Bike lookup: Is this the bike I ordered or a women's model?

As Swifty said Specialized does not have men's or women's bikes starting with the 2020 model year. Here is a link to their hyper buzz worded article on the topic "BEYOND GENDER".
To illustrate the truth of no more genders go to the website for Specialized shopping for Rockhoppers

Filter for MODEL YEAR 2019
Notice that men's bikes and women's bikes are listed.
Remove the filter for MODEL YEAR = 2019
Filter for MODEL YEAR = 2020
Notice that the gender qualifier is missing from the bike names in the results.
Leaving the MODEL YEAR filter set to 2020, flip the GENDER filter back and forth between Men and Women.
Notice that the same bikes are in either Men or Women, or both.

No "Men's Rockhopper" or "Women's Rockhopper" only "Rockhopper" for 2020
At the bike shop you must have tried a different model or year of Rockhopper.
According to the sizing chart from an authorized Specialized dealer:

If you are 5'6" to 5'10" you would ride a medium.
If you are in the range for the size of bike you have I'd take it back to the shop and have them fit the bike to you.
No matter what the chart says if you are unhappy with the size you can exchange it.
Specialized has a 30 day return policy
From the Specialized FAQ:

Can I exchange an item if it doesn't fit?
We realize that buying items that are size-specific over the internet is difficult. Because of that, we offer a 30-day satisfaction guarantee on products purchased from our webstore.
Upon receiving your order, if you find the need to exchange an item for the same item in a different size or color, we can help. However, if you want to switch to a different item, then you'll need to return the item for a refund and order the new item separately.
We will send out the replacement item(s) on exchanges within five days of receiving the original item back. We will send it via Fed-Ex 2-Day air, at no charge to you, to the address from the original order.


If your time isn't worth much and you like to tinker (like me), at least take your current fork apart and see if there's anything you could do to improve it's situation.

That said, based on your description of it's problems, I think you should buy a new one. And I actually mean new, in this case. Normally it's better to buy a used bike than a new one, but with something that's as age-sensitive as a suspension fork, I'd buy a new one (and take care of it, maybe get a stanchion boot).

As to what fork you should get... take note of the specs of your current fork (brake options, wheel size, stanchion size, travel) and get something similar. $150 will get you something decent.

If you decide to get something new, Amazon, Ebay, and your LBS are good places to look.


Why are my quill pedal cages "wobbling"?

it looks to me like the cage part of the pedal is pressed together you may be able to remove the pedal and pound the end of the cage part back into the frame of the pedal thee type of connections are held together by distortion of the metal ie widening of the end of the piece to be held by widening by pressure like a rivet so possibly u could re hammer them together


Using compressor gauge to determine tyre pressure?

The little thing you operate with your finger controls a valve, opening the circuit from the compressor to the tire. Once you release the trigger, the valve is closed and the gauge will measure the pressure in the tire and in the little hose connected to the tire (if the connection to the tire valve is tight). The compressor will be isolated by the valve.

So, what you have to do is:

connect the hose to the tire valve
pull the trigger for a short time
release the trigger
read the pressure
if the pressure is not enough go back to 2

What you don't do is:

pull the trigger for long time: you are not inflating a car tire. The first time I let somebody use it for inflating my tires, I ended up with an exploded tube (they were used to inflate car tires)


What to look for when buying a single gear bike?

Some other items you might consider:

Most importantly, the fit of the bike. If you are 6'2, you will be on the high end of normal sizing, and not all models may be available in a suitable size. Staff at any decent bike shop should be able to measure you, and suggest a range of suitable models however. Take them for test rides and make sure you don't experience knee pain or back pain.
Weight of the bike. If you will ever have to carry the bike, this can be quite important. For example, if you live in a flat above ground level, and don't want to leave your nice new bike outside at night where thieves can get it. Single speed bikes tend to be lighter anyhow, so you should have no trouble finding a cheap model that's still under twenty pounds.
Low maintenance design. If you want a low maintenance bike, single speeds are a great start. I'd also look for a coaster brake (back-pedal brake), and a nice chain case, possibly even a full chain case if you can bear the weight. An aluminium frame may also be a plus, as ChroMo (Steel) will rust relatively quickly without careful maintenance in wet climates, especially if there will be salt on the roads in winter.
Fenders if you ever plan to ride in rain, mud, or snow.
Rack Mounts if you ever plan to carry something heavier than a backpack. Also useful for riding in the heat.


I think you have the right idea - build up slowly. I've seen a few people with little kids out cycle touring, and did a couple of weeks with a group that included a mother and pre-walking infant. The people below apparently managed at least 1000km based on Moz's comments.

I think the main limit is how long your kids can handle being on the bike or in the trailer. Remember that your kids are not exercising, so they'll get cold easily. And bored, unless they can see out easily. Ideally you'd be able to make eye contact and talk to them, and not just by having the other parent ride up next to them.

These days I'd be tempted to buy one of the long john kiddy carrier bikes (like the Gazelle Cabby), because a kid in an open-top box is likely to be happier than one in a noisy bag-on-wheels.

But start with the gear you have - drop the kid(s) in whatever you normally use to transport them, go for a long day ride, see what happens. If you all  survive 80km today and 80km tomorrow, an 80km each way overnight trip sounds very feasible. Just keep working up and see how you go. I'd personally start with backyard camping, because if your kids hate that then you will need to tour between motels or B&B's, and you really want to find that out now rather after 80km of riding. Same applies to your fellow parent, BTW :)

I am a big fan of specialised bikes, and if you have the budget there are a lot of ideas out there that you can try and buy. Trailers are a compromise, they're slow, heavy, have lots of wind resistance, and are not a lot of fun to be stuck inside for long periods. For a bit more money you could buy a dedicated long-tail bike, and that's at least more comfortable for the kid as well as lighter and faster (plus easier to park!). Then there are proper load carrying bikes like long johns and the 8-Freight. Those carry more and have more load space, so you get a trailer-sized volume of luggage and child, but in a place you can see it. Even bigger are load trikes (Nihola not Christiana for touring, the cart-axle steering only works at low speeds and for short trips), or things like the Greenspeed Ute (recumbent) or a rickshaw like the Trisled Ute (upright). But real load carrying needs four wheels, and Treehugger has an overview. Quads are unfortunately expensive and not especially popular, so tend tyo go in and out of production. But the smaller manufacturers will often build you one even if it's not on their website any more, so it's worth asking. In the UK they're lucky enough to have dedicated recumbent and load bike shops, but in the USA not so much (AFAIK).

I normally do short tours on a recumbent bike (because it's easier to break it down for transport), and longer tours (anything over a week) on a four wheeler. Mine is 2WD for off road tracks, but other than that it's just a conventional recumbent with a big box on the back for all my stuff. The win for me is stability (I can look at the scenery), load capacity (I just throw everything in the box) and, well, I just really like riding it.


The shifter for the front derailleur is "soft" in my vintage bike

At first glance I see the problem you are having .

Those are NOT friction shifters . They are positron shifters .

Research Shimano Positron Shifters for a more definitive explanation

This was Shimano's earlier attempt at an indexed gear system.  Also known as "Positive Pre-Select" or PPS.

The main differences are that the indexing is in the deraileur rather than in the shifter on the handlebar.  As a result, the bowden cable is a full housing and has a thicker solid inner rather than a woven stranded cable.

Upshot - you can't just fit any old cables to the rear mech.  However its possible the front deraileur is just a standard non-indexed friction shifter.


Fixie/Single speed frame information for beginner

Building a frugal dumpster/secondhand singlespeed or fixed gear is definitely one of those tasks that has become much more difficult with their growth in popularity.

So, let's say you've found a frame that's in your relative size range.  You've figured this out already by riding other bicycles and visiting bike shops and figuring out a rough range of acceptable seat tube and top tube lengths.  And you obsessively carry around a metric tape measure (probably not that hard in Europe).

The first thing to check when selecting a frame is its suitability for conversion.  For a fixed gear or singlespeed without chain tensioner that means it needs to have horizontal dropouts or track ends.  (Expensive options like an eccentric bottom bracket or sliding dropouts would work here as well, but those are rare to find on inexpensive frames.)

The next thing to consider is completeness relative to your parts supply.  A frame with fork is almost always better than a bare frame - finding compatible road forks, particularly threaded, can be annoying as there are a number of odd old sizes out there.  If you've got no parts to start with, a complete bike makes a good base point.  Singlespeeding a complete bike is relatively trivial - remove the chain, remove the shifters and derailleurs, and then shorten the chain and reinstall it over your preferred gear combination.  As you find additional parts you like you can replace them piecemeal.

As far as damage goes, the main stress points to look at are going to be where the rear dropouts meet the chainstay and seatstay and where the seatstays meet the seat tube.  But give it a quick gander at all the joints to look for any obvious cracks.  You'll also want to check just behind the headtube for any sign that the bike has been in a front end collision or roof rack crash.  In general, any kind of bunched-up paint is usually a sign of a bent tube and a compromised frame.


former weightlifter turned triathlete repeatedly breaking hanger

The way you asked the question, it sounds like you think the following is happening: first, the derailleur hanger wears out/weakens, then it snaps, and this causes the derailleur to go into the spokes.

It is much more likely that the chain of events is the following: the derailleur is mis-adjusted, when you shift to the largest cog on the rear, the derailleur goes into the spokes, and this causes the derailleur hanger to break off.

Possible causes:

the inner limit screw on the rear derailleur is too far out, needs to be tightened a bit, until it reliably keeps the derailleur from moving too close to the spokes
the chain is too short, and when you shift onto the largest rear cog and the largest front chainring (not recommended in general), the chain gets too tight and this rips off the derailleur.


Why is my chain riding up and skipping teeth on the freewheel?

Need better pictures to get a clear idea as to what is going on here, but assuming that the chain tension is good and the derailleur spring is okay, I'd check to make sure your derailleur hanger is straight. Especially on older derailleurs, this can allow the chain to be received by the cogs at an angle whereby the cog above and/or cog below can 'trap' the chain.

Checking the hanger is easiest with the right tool, it's a bit pricey ($60 - search on "Park Tool Derailleur Hanger Alignment Gauge - DAG-2") so best bet would be to hit your local bike shop and have them lend a hand.


The significant numbers are the "50-559" which translate to 26" x 1.90" – my best guess is that what you're seeing is a molding problem that causes the '6' to look like a '5'. The 50-559 is the ISO size of the tire. The first number is the width (50 mm) and the second is the "bead seat diameter" (559 mm).

Beware of 26" tires – there are two sizes that are called 26" and they are not compatible. The easiest ways to tell them apart are by the width where you will see either a decimal width, say 1.50", or a fractional width, say 1 1/2". The other method is to compare the ISO size which would be something like 37-559 for a 26 x 1.5 inch tire or 37-590 for a 26 x 1 1/2.

For riding on roads slick tires are nice, they give you the largest contact area for a given tire size. You need to balance that against durability and availability. Tires like the Schwalbe Marathon are built for durability, but aren't really slicks (at least not in the sense of a tire like the Kojak). Do look for a tire with a "slick" strip down the middle which is where you'll be riding most of the time.


Are there any sub $100 gps devices that can export a gpx file

Instead of an actual GPS device, I would recommend buying a used smart phone, (The Strava app itself only works on either iPhones or Androids). A "Nothing Special" used smart phone you can usually find for maybe 40 bucks, depending on the model and brand.

Download the app and just take the phone with you wherever you ride. It's not a fancy system, but it works. This is the method I use now.


Gary Fisher Kaitai suffers from handlebar wobble at moderate speed with 10lbs on rear rack

There are a few things that could help the shimmy, but there is no real silver bullet.

Typically the shimmy is a function of head tube angle, top tube length and frame (specifically top and down tube) elasticity. Jobst Brandt describes it best in this article so I won't get into too much detail on the whys. There are a few things that reduce or negate the shimmy that have worked to varying degrees for myself.

1) Knees against the top tube. Squeeze the top tube with your knees.
2) Stem length. Sometimes a longer stem might help out. Very frame dependent and you would not want to change your fit imo.
3) Handlebar bag. Distribute some weight to the front and see if a handlebar bag can help overcome the gyroscopic forces created by the wheel.
4) Switching to a set of tyres w/ more 'tread' (ie. knobbies). I haven't tried this but the jobst brandt article indicates this could work.

The Kaitai is pretty unique in its long top tube, exceedingly short head tube and relatively steep head angle. This also makes the bike a 'tough fit' for the majority of people.


Is there a reason for levers to be reversed on bikes with hydraulic brakes?

It's not for hand signals. "Left hand only" signals were originally designed for cars. You couldn't use your right hand out the window, so you could only use your left. Using both hands to properly signal on your bike is far more clear. It's used on motorcycles due to the fact that the throttle is on the right hand, so you want to keep that engaged at all times.

Reversed brake routing (front on the right, back on the left) is called "moto" routing and is primarily used in MTB and cyclocross bikes. On a CX bike, it's done so you can have greater controlled braking with the left hand on the back brake while your dismounting your bike for a barrier and your right hand is on the top tube. The front brake offers more power, while the back offers easier minor speed control while approaching a barrier.

To answer your initial question, there is absolutely no reason the brakes cannot be switched on your bike. Either the mechanic is lazy or doesn't know how to work on hydraulic brakes. In either case, you should take it to another more capable shop.


The chain will travel less distance sideways, so less, but still if you are big front, big back, it may still touch the front derailleur. I wouldn't call it something to worry about though.


Frame manufacturer not covering crack as saying it was crash damage

Despite what others have said, a warranty is a bona fide contract between the company and you. It's used in the selling of the product thus is covered by decent consumer protection law (in the UK anyway). This article from Which suggests a good process to follow.

Keep a record of the contact with the company, try to follow their warranty procedure. If you're sure that the warranty exclusion isn't valid (crash damage), then it'd be worth getting an independent opinion on whether or not the crack was crash damage. A good bike shop should be able to write something up for you. Then show that to the company.

If you end up in a deadlock with them, then contact the financial ombudsman. Another avenue to follow might be section 75 of the Consumer Credit act.
"Don't forget that if you pay for anything with a credit card between the value of £100 and £30,000, your credit card company can be jointly responsible for any faults that develop. You can either claim for a refund using Section 75 of the Consumer Credit Act or, if you are looking to get the product repaired, you can claim for the cost of repairs."


A few things off the top of my head:

Not enough brake cable tension.  This is very likely if it's fairly new and hasn't been tuned up -- brake cables stretch over time, especially when new.  The amount of stretch can be more than the barrel adjuster can compensate for, so you would need to actually pull more cable through the cable clamp on the caliper.
Broken (or worn out) caliper spring.  Less likely, but you should be able to see if it's broken, depending on the model of brake.  Your LBS might also be able to replace the spring rather than buying a whole new caliper.
Frayed cable or housing causes cable to "catch" and not spring back.  Might be harder to find, you'll need to inspect the cables and housing for damage (may need to pull the cable out completely).  The good news is that these are relatively cheap & easy to replace.


While most shifts rely in the very position of the shifter to precisely place the derailer aligned with the cog, the last gear relies in the limiter screw in the derailer itself. So, the last gear usualy "let the cable go" a bit more than needed, so that the limiter screw handles it.

Also, in the last gear, the derailer spring is almost unloaded, so that extra release of cable helps the last shift to happen.


Using 9 speed Deore front shifter with 10 speed Ultegra front Deraileur

Front derailleurs don't care what you have in back (as long as the chainline is within reason). So you can ignore what's going on behind the front derailleur.

In terms of matching shifter and derailleur, an indexed front shifter needs to match in terms of capacity (3x), make/series, and capacity (tip of the hat to @mikes).

Fortunately, the Deore and Ultegra front shift points are largely compatible even though one is from the mountain bike line (your Deore shifter), and the other from the road bike line (Ultegra f. derailleur and crankset). Because you're using an indexed front derailleur with a different series shifter, you may need to tweak the indexing a bit but you should be able to get them to work. Many people use MTB triple cranks on their road bikes because of the wider range available, although you're doing the opposite here.

Life was easier with friction shifters.


Should I avoid sitting on top tube on my carbon bike?

I have never had or heard of a problem.
Over at www.velominati.com, one of the rules is

Rule #80 // Always be Casually Deliberate.
Waiting for others pre-ride or at the start line pre-race, you must be tranquilo, resting on your top tube thusly. This may be extended to any time one is aboard the bike, but not riding it, such as at stop lights.

While some of what they say is tongue in cheek, this one is not. Most people I know do it, and have done for years.


Experience with GPS trackers - thieves' reactions?

I've got a friend who had a cellphone stolen.  She used the provider's tools to locate the phone down to a suburban address, and went to get it back.  The teenager who answered the door knock said there was no such phone there.  Her brother called it and they heard it ringing in the background.  Some more people turned out of the house and denied her entry.  She phoned the police with this info and they weren't interested, plus advised her that entering the house to recover the phone would be illegal and that she should write a written official complaint at the police station.  She went to the police station to do a report. Her phone was turned off/wiped before she could demonstrate the location to the officer taking the report.

The phone was never recovered.

Answer GPS tracking by itself isn't going to save your ride.   You need a multilayered approach of locks, safer location, uglifying, and co-parking with nicer bikes.  Or park it inside with you.

I am fortunate to work for a company where 25% of the staff ride.  So we have dedicated floor space for secure bike parking inside.  At home my bike lives in a locked garage.  So I don't ride with a lock normally.  If I have to stop elsewhere I'll generally ride the beater MTB and a lock, rather than the nicer road bike.

Sorry its not a bike, but its relevant to GPS tracking and recovery of stolen items.

Edit:  Clarifying - location information by itself is pretty useless.  You need to be able to get support from the police to make use of the location info to get your stuff back.  Simply rocking up to the door could go either way.


What are the disadvantages of securing your foot to the pedal?

The only disadvantages I could think of are:
- The higher price for clip-less pedals and the need to have cycling specific shoes (which are usually not comfortable in walking)
- Not being able to comfortably ride your bike with normal shoes again. However, you can overcome this by going for dual sided pedals.

On the bright side, you get to use different muscles while pedaling which make cycling more comfortable. You eliminate the chances of your foot slipping off the pedal and getting your leg hit.

When I first started using clip-less pedals, I only fell once. It was because I forgot to un-clip at the end of my ride. Now, if I was going to fall off my bike for any reason, I can smoothly and quickly un-clip my self to prevent the fall.


Can I use a thru axle with a longer pitch when the manufacturer specifies a smaller one?

I think you are perhaps confusing the thread pitch with the length of the threaded section of the axle - as your title says 'axle with a longer pitch'. The pitch is the distance between threads in mm.

You definitely cannot use a through axle with a different thread pitch than your frame, it would not screw into the threaded right hand dropout.

To figure out a compatible through axle, you need to know:

Total length - which depends on the hub width and thickness of dropouts
Length of threaded section - the match the right dropout
Pitch

You already know the pitch1, hub width is 142mm, dropouts can be measured. Armed with that info you should be able to find a matching axle.

Here's a resource I find helpful: http://blog.fairwheelbikes.com/reviews-and-testing/high-end-skewer-review/all-about-thru-axles/


How to fix cross-threaded derailleur hanger?

If its a replaceable hanger, simplest option is replace it.

If not you might be able to repair it with a 10mmx1mm tap. If that does not work, a Helicoil type repair is possible. Its one of those tasks if you are not 100% confident you can do right first time you might be better off handling over to a shop (An engineering shop or well equipped bike shop) as it is possible to make it worse.

Refer Park Tool Basic Thread Concepts


What is the lever on the head of my floor pump for?

You press the chuck onto the valve, then pull the lever up to lock the chuck to the valve.  Otherwise pressure could blow the chuck off on higher pressure tires.


iPhone app to follow/navigate an imported .gpx

http://www.motionx.com/ is the closest I've seen. You can set it's map to show track up as you ride. It doesn't know where the roads are though, nor zoom in or out depending on your speed, nor show upcoming turns.

NOTE As of 2019, this app is now end-of-lifed. It was great while it lasted.


Dual electric/pedal bikes to solve pedalling effort issues

Not sure if I understand your question correctly, but I take it you want to ride unassisted during training/recreational rides?

I don’t have much experience with electric bicycles but as far as I’m aware the motor often has its own free-wheel and therefore should contribute very little friction/resistance when it’s not running. The disadvantage of such a free-wheel equipped motor is that regenerative braking is not possible. So if you remove the battery the only major disadvantage of an electric bike should be the mass/weight of the motor and charging controller. With front wheel drive it should even be possible to swap the whole front wheel+motor for a normal wheel relatively quickly.

Of course many electric bikes come with “comfortable” seating positions, heavy frames and other heavy parts. This doesn’t help when you want to ride unassisted.

Regarding

  the bike seat had to be lowered to suit my short stature, so that I
  can put my feet on the ground when I stop.

It shouldn’t be necessary to reach the ground while sitting on the saddle. Get in front of the saddle just before you stop and you should be able to reach the ground just fine. There is only one requirement for saddle position: It should allow you to ride powerful/efficiently (and without damaging your body). You should never lower it to reach the ground or move it front/back to compensate a long/short top tube.


How do you distinguish a touring bike from a speed/road bike?

The distinctions are often subtle:

The touring bike will of course be slightly more heavily built (generally a steel frame).
The touring bike will have a longer wheelbase.  You will generally notice that the space between the seat tube and the rear wheel is fairly wide.  (The longer wheelbase serves 3 purposes:  More stable, smoother ride, better fender clearance, and better heel clearance for rear bags.)
The wheels will be more heavily built (at least 32 spokes and maybe even 40 on the rear), with wider rims and tires -- at least 28, maybe 35-38.
The touring bike will have eyelets on the front and rear dropouts to support racks and fenders.  (This generally means two eyelets on each side of each axle.  Plus there may be braze-ons about half way up the side of the fork for a "low rider" front rack.)  And at least 2, perhaps 3 sets of bottle bosses.
The touring bike will have a more "relaxed" geometry -- higher bar height, a little less "reach" (shorter top tube, etc), slightly more slope and "rake" to the fork.
The touring bike will have a wider gear range and a lower low gear, and usually not as high a high gear.


Hydraulic Brake Loud Noise and Vibration

As suggested in the comments, follow the burn in procedure. If that fails, then you can try to reset the caliper alignment (follow the installation instructions or one of the many sites on the internet). Also clean the disc with a volatile oil solvent such as alcohol or methylated spirits.

If that fails, it may be your pads - what did you have and what did you replace them with? Organics tend to make less noise but don't perform as well or last as long, metallic compounds tend to be better performing material and last longer but are more prone to noise.


Could paint build up on a bottom bracket be considered a warranty issue?

It is normal and acceptable for a frame to be delivered with paint needing to be removed from the bottom bracket shell, headtube, and seat tube areas.

It is assumed that a qualified mechanic with appropriate tools available will be assembling the bike, and that preparation of the frame is simply one of the necessary steps in the build process.

Indeed, most every bike company requires that the frame be assembled by a qualified mechanic (and in some cases by a mechanic certified by the bike brand) in order to maintain the warranty on the frame or the bike.

Unless there is something preventing the frame from being prepared properly, then this is unlikely to be considered a warranty issue.


What rear shock will fit my Scott spark 2009?

From your bike manual:

Piston stroke: 37mm

Shock (Eye to Eye): 165mm


By definition, dismount means to get off the bicycle. That means you should not be straddling the top tube, but should be standing next to the bicycle. Then, you can walk the bike if needed. This is the safest bet, and the one you should use unless you have additional information.

You shouldn't just get off the seat and pedal with one foot or waddle, unless you have additional information that says its okay in that area.


On most frames, yes, you can put as much of the post into the frame as you'd like. However, you are likely to remove graphics, and scratch the top coat of the carbon, so if you care about things like that, don't put it farther into the frame than is necessary.

If it is a permanent position, cut it, as suggested above. Be sure to check the manufacturers' recommendations for your post. Not every post can be cut to any length.

If you need to, try to put it at that position, gently. If anything stops, sticks, blocks it, or doesn't feel right, stop.


is it worth to change slx 2011 rear derailleur for xtr 2009?

In my experience, the differences should be so small that I wouldn't botter the trouble just for the sake of change.

But, if you have a GOOD REASON (noticeable performance or weight difference for intended use), then XTR, even 2009, should be better than a brand new XT, although I think both are very nice - to the point you cannot tell the difference if you couldn't look at them or know which is which while riding.

In the end, personal taste and preference would determine the best option, I think.


My fork stem is rusted - should I replace the forks?

The corrosion can be removed from the steerer with no problems.

If the corrosion was bad and extended into where the top headset bearing sits, there might be a problem as the steerer would not fit into the inner bearing race properly. I can see that is not the case here. (Interestingly you can see where the stem and spacers are positioned on the steerer from the corrosion patterns.)

Clean the corrosion of with a coarse steel wool or high grit emery cloth. Get some decent assembly grease and put a light coat on the steerer, and the stem bolts, interface between stem and handlebar etc.


What's this cotter pin on the barrel adjuster for?

I pulled the cotter pin off and it turns out there's a spring inside the grey knob that pushes it down to the blue frame piece.  That engages the 4 bumps on the grey knob with the 4 dents in the frame (giving 4 index positions per rotation of the knob).

Seems like the cotter pin was meant to be removed all along and maybe only acts to hold the grey knob and spring in place before the barrel adjuster is installed on the frame.  I'm not 100% sure that this is the answer to my question, so wanted to throw this information out there before accepting my own answer.


Cadence meter for the Shimano Ultegra Flight Deck 5601?

The Shimano Flight Deck computers use 'virtual' cadence. There are switches fitted to the shifters that tell the computer which gears you have selected. The wheel sensor tells the computer how fast you are travelling. The computer works what your cadence is from there.


Free Spirit "Brittany Te12" Part Identification/Upgrade

tl;dr: knowing the parts is useless. You have a caliper, now you just need to remove everything and measure everything. You will learn something just by disassembling this bicycle and not focusing on brands, just on dimensions and "mechanics" of the parts you are removing.
Then, about reassembling it, it will cost you 5 times the money and 50 times the time+effort with respect to a bicycle shop.
Disclaimer: I do not own a bicycle shop.

The parts currently installed have no value and will provide very little information on their own.
You can still disassemble them and try to understand a thing or two on how they are assembled and maybe how they work, especially about the derailleur (springs, limiting screws and so on).
Bottom bracket and cranks are good to be recycled (=scrap metal), as well as the chain and whatever is installed on the rear wheel as a cassette.
New bottom bracket and crank ---> most likely new chain line. Which is not that bad considering that the wheels will almost for sure need a good clean (greasing the hubs and so on) and you may discover that they are in bad conditions, so counting them temporarily as scrap metal as well, the new chain line is less of an issue (you have a lot of freedom once you have to replace bottom bracket, crank, rear wheel).
So remove the bottom bracket, check whatever size is relevant.
Then check the fork. Remove it, give it a thorough clean and a good examination, check for cracks in the fork or for deep rust. You do not want a fork that breaks in half while sprinting across an intersection, nor while you are just coming up/down from the curbs.
Check and note wheels size.
Save the frame, maybe the fork, then you have a lot of freedom in how to reassemble this bicycle.
I forecast something on the order of at least 3/400 USD/EUR/GBP, only for the parts (assuming you have all the needed tools for cassette, bottom bracket, fork, etcetc).


Anyone found a good way to transport kids with a Strida?

It appears that one might possibly attach a lightweight trailer to that rack sort of deal on the back, or possibly to the seat stay.  Since the thing has such a short wheelbase with the rider's weight so far backwards, there would be a bit of a problem with the bike doing a wheelie, however.


RB not ridden in 4 years unable to shift gear

If people can figure out what the problem is, you can probably fix this yourself without needing specialist tools. Honestly, though, take it back to Halfords and get them to actually do the work you've presumably already paid them to do, because this is pretty ridiculous.

In general, I'd recommend taking bikes to a specialist bike shop rather than somewhere like Halfords: the level of clue is generally much higher and they'll actually make sure the bike is working before they hand it back to you.


Is 25 km/h average speed good? What speed should I aim for?

There is no such thing as an ideal speed you should be aiming for.  It doesn't matter how fast you ride, there will always be faster riders, and there will also be slower riders.  The main thing is that you give it your best and try to enjoy your ride.

At events here in the UK it is typical to see riders averaging from 16-35km/h and everything between.

Edit: Advice above is for a typical sportive ride - if you have intentions to race things are a bit different and you should expect to need to be able to hold a bunch travelling at 35-40km/h for 2hrs for entry level road racing.


Determining the correct chain length (52/36 with 12/29 11S cassette combination)

From the picture, it's clear you have a "short cage" rear derailleur. That could be a big contributor to the problem.

Rear derailleurs are rated for a certain maximum "capacity" that they can handle, which is the difference between the smallest total number of teeth and largest total. In your case, your system goes from 12+36=48 teeth to 29+52=81. This requires a capacity of 33T. Suppose your chain is almost snug when shifted into the 29 + 52 combination, so that the derailleur's tension pulley is almost horizontal, and then you shift into 12 + 36, the derailleur's tension pulley has to then pick up 33 teeth of slack.

A 33T range is about right at the edge of the capacity of a typical short cage derailleur, which is probably why you're having trouble setting things up to be okay at both extremes. It would be more comfortable with a middle cage length unit.


Uneven tension on Gates Carbon Drive belt

Addressing question 1.

I understand that to measure the tension you pluck the belt and app measures the frequency. Anyone who plays guitar will know a string sounds differently when is plucked near the bridge compared to plucked closer to its center. Plucking near the bridge suppresses lower harmonics.

The app instructions should tell you where to pluck the belt, but halfway between the chainring and sprocket is probably the correct spot.


Is this a good source of food for 25-50 mile ride?

The EXPERIENCED CYCLIST, who is not, eg, out of shape after a long winter does not need any food for 50 road miles.  This is because his muscles and liver have "learned" to store extra sugar/carbs to provide energy over a long period of time.

But a beginning cyclist who is not, say, already a distance runner or otherwise used to exercising vigorously for several hours DOES need some extra carbs along the way to keep his blood sugar up, not, perhaps, for a 25 mile ride, but for a 50 mile one.  (Note, you DON'T want large amounts of fat or protein -- these do nothing to help your sugar levels and they are hard to digest.)

The form of the carbs is not especially critical, other than the food should be chosen for convenience, neatness (you don't, eg, want chocolate smeared all over your hands), and personal taste.

Avoid foods with any significant amount of fat, and avoid spicy or strongly flavored foods -- these may seem appetizing at the store but do not go down well or "sit" well on the road, especially if you allow yourself to become a hair dehydrated (which of course you shouldn't do, but it happens).  A modest amount of salt is desired, but too much (without enough water) can send your stomach on a spin.  (The nut-raisin snack, by itself, is just a tad "heavy" for my taste, and may be a hair too heavy in terms of fat.  But as one of a small variety of snacks it's fine, and likely a decent source of salt.)

I would say figure on about 500 calories of mostly carb snacks for a 50-mile, 3-hour ride.  This isn't nearly enough to replace the calories you burn, but it is enough to prevent a low blood sugar condition.

And, of course, HYDRATE!


Lighting control isn't exactly a good idea since you have 2 lights (front and rear) on a bicycle typically.

Most cycling sensors (cadence, speed, heartrate, etc.) either speak ANT+ or Bluetooth these days, so if you want to read sensors, you just need to know how to speak ANT+ or Bluetooth in your chosen language. You can also add a GPS module and other things as well.

People have accessed USB ANT+ sticks in Python and Bluetooth has a cycling profile and many people have used Bluetooth with the Raspberry Pi.

Note that many phones have both ANT+ and bluetooth, and have their own built in batteries (and are probably faster than a Raspberry pi) and mobile internet, so if you want to read sensors, they may be better than the raspberry pi. That being said, either of these options will likely be far more battery draining than a cycling computer which provides the same functionality, so I'm guessing this is a project just for fun.


Is it possible to change the bike’s friction shifter into a trigger shifter?

Yes, this is possible. You just have to select trigger shifters that are compatible with your derailleurs.

As far as as know, Shimano only offers twist shifters in their low-level Tourney range, which are all rear 7 or 6 sprockets, and either triple or single chainring cranks. You just need Tourney shifters that match the number of sprockets in the rear and chainrings in the front. There are several models of Tourney shifters but they are all interchangeable.

The same principle should hold if you SRAM gripshift twist shifters and derailleurs.


What's the deal with Rohloff and Gates Carbon Drive?

Rampant Guess: Given how much Rohloff likely values their reputation (the hubs are hailed for their longevity under poor conditions) they are likely being extra cautious as the set up might produce poor results under some conditions.

Gates belts require a lot of tension to operate correctly. This can be hard on hub bearings and could potentially twist a frame if is not designed for it. There is a lot going on inside a Rohloff hub, I suspect twisting could put important hub parameters out of specification, which could shorten the hub life. Being risk adverse to any tarnish on their reputation it sounds like they are trying to tightly control this potential problem.


I've experienced 2 problems on the Sora shifters- one condition was the cable wear caused strands of the cable to break- eventually all broken strands resulted in functional loss & cable replacement needed. When I disassembled the shifter, I found small pieces of the broken cable strands jamming the ratcheting mechanism. You may be experiencing a similar condition if the shifter cable has been previously replaced w/o a complete overhaul of the shifter. As the strands started breaking- the shift action deteriorates, and no click latching was one of the symptoms.  A second problem found on another Sora shifter that had similar shift deterioration was a result of a tensioning spring used for the return action- the 90 degree bend point of the spring was broken. Without an available replacement part, I finally mechanically "unwound" 1 loop of the spring to create a new 90 degree bend for the part. It successfully has been working for several years now on that bike.


I suspect that your brakes are misaligned & are rubbing on the tire.
The brake pad should be centered on the rim braking surface, look closely & you will likely see that the pad contacts the tire when the lever is pulled.

Not only does the pad touching the tire wear out the sidewall, but it also generates heat which damages the tire & inner tube which could cause a catastrophic blowout.

I would fix the brakes & then immediately replace the the tire(s).


Has anyone ever tried to estimate peter sagans ftp and 5 sprint power, if so what would they look like?

I found a discussion of Peter Sagan's SRM data from an early stage in the 2012 Tour De France.

Also an article which discusses normal power output for various effort durations.

What matters for sprinting isn't their FTP, rather it's their power output over 5 seconds, 1 minute, 2 minutes... For the last 5 seconds a top sprinter will be pushing 22-25 W/kg, whereas 6.0 - 6.5W/kg is realistic for HC climbs.

In addition to his weight advantage, Cavendish is also one of the most aerodynamic road sprinters. This article suggests a 10% decrease in CdA can result in a 3 metre advantage in a 14 second sprint. That's a humiliating margin.


Bicycle Trailer Hitch Design Considerations

The requirements for hitches for single wheel and two wheel trailers are different.
3 types of rotation through this joint: Pitch, yaw, roll.
Pitch: as the bike transitions up to a ramp,
Yaw: to allow a flat turn,
Roll: A two wheel trailer will stay flat while the bike leans into corners. A single wheel trailer will fall over if it's not constrained.
The Surly hitch has the X-shaped component providing yaw and roll, and the axle ends have bearings in them to provide freedom to pitch.
The BOB tailer allows pitch at the axle, but the joint before the platform only has 1 degree of freedom, allowing yaw. The trailer can't roll independently of the bike.
The mounting point differences change the impact of the tongue weight on the bike dynamics. Seatpost clamps are simpler to design and use and allow tight turns without bike-trailer contact, but increase the torque created by the tongue weight. Mounting at the rear axle minimises the torque, but all the load will be added to the rear wheel, and the trailer has to be further from the bike to avoid contact with the bike or your heels in sharp turns.


Does this carbon fork have a crack in it that would make you replace it?

What is visible in the photo is a paint scratch. Letting the bike simply fall over will not structurally damage carbon fiber composite. People seem to think CFC is fragile but it’s really quite robust.
The fact that you had a collision is much more worrying. How hard? At what angle?
Hard, head-on collisions can certainly damage the frame or fork. The stresses are higher in the head tube or steerer area as the fork acts like a lever. Often damage to the head tube can occur but the fork is un- (or less) damaged.


Need assistance identifying new tire options for Fuji 4130

26x1.80

26 means 26 inch and is the nominal diameter of rim and tire. It basically means the smaller type of wheel used on older MTBs, with a rim diameter of 559mm. ('27.5' - 584mm and '29' - 622mm being the other sizes in more common usage now.) 1.80 is the nominal tire width in inches also.

Some MTB tire manufacturers still use the inch measurements, some use the ETRTO size system which uses millimeters.

You definitely need a 26'/559mm MTB tire, but you have choice in tire width as a range of widths will fit on a given rim width. The safe choice is to stay with 1.8", but you could go a little wider if you frame and rim brakes have enough clearance.


Ball bearings only on one side, and smashed "ring"?

There are supposed to be ball bearings on both sides of the hub. You need to rebuild the bearings replacing at least the non-drive side balls.

Bicycle hubs with loose ball bearings use a ‘cup and cone’ system. The cups and cones have the bearing surfaces and the balls are sandwiched between them. The cups are in the hub, the cones are threaded into the axle.

There are many videos on YouTube that will show you how to disassemble, repair and reassemble a cup and cone hub. RJ The Bike Guy has a good one.

You’ll need to inspect the cup and cone bearing surfaces for wear or pitting. the axle, cones, spacers and balls can all be replaced. Balls come in a couple of different sizes. If you don’t have accurate calipers a local bike shop can help you out.


It sounds like one of these situations where walking, at the sustained pace of 3 mi/h - 4.8 km/h will do the job.
Think about the time you will need to set-up the bike to fit in the car. Probably you cannot remove the front wheel from the bicycle, because they use special lock to avoid theft.
However, you face two solutions:

If you are fit to cycle, you are fit to walk or even run to the rental car agency. It seems weird, but hey, bike rental were a weird things until 5/10 years ago!
the bike will fit inside the car, at least partially. keep it in place with bungee cords, and use bungee cords to keep the bicycle in place, as well as those "flat section ropes with metal hook used to move furnitures" to keep the lid partially closed and the bike inside.

Take into account that the car will possibly prevent your gearbox to shift on a gear >2 with the trunk open.
Every car has at least a couple of hooks inside the trunks.
What car are you renting? a Smart or a SUV? what bicycle is the bicycle? 20 inches wheels or 28 inches wheels?


How do the wheels attach on this trike design?

How do the wheels attach?

The instructions never illustrate how the wheels attach to the frame so all we can do is guess.

Looking at the picture (the vehicle is facing left)

The wheel bolts to the steering rack - attaching something like a wheelchair wheel.
The there is a black verticle rod with a black ball on top on each side used to pivot the rack and steer the vehicle.

(The vehicle is facing right)

The wheel bolts to the end of the "steering bridge".
The only place I can see to attach a wheel has been marked in the picture above.

It would be wonderful if the instructions had illustrated the arrangement of the axle bolt, washers, and nuts.


Why front hub axle sticks/freezes when riding extreme downhill

There is supposed to be a locknut on the axle, as well as the cone.  When adjusting the bearings it's important to get the locknut quite tight against the cone, so that the pair cannot rotate on the threaded axle.

As you've found, if the cone can rotate then it will, from the rotation of the wheel.  The left side will get looser (but will be somewhat limited from getting real loose by the axle-fixing nut or skewer) while the right side will get tighter (with nothing to prevent it from getting very tight).  If both move together the axle will "migrate" right over time.  If the left side is prevented from moving (either due to the fixing nut or a properly set locknut) then the bearing will get tighter and tighter.

To tighten the locknut properly you generally need a thin "cone wrench" of the appropriate size, to fit the narrow flats of the cone so it doesn't turn as the locknut is tightened.

It is a little tricky doing this, as, when you tighten the locknut, the bearing adjustment is inevitably changed slightly.  So you have to slightly misadjust the bearing, then tighten the locknut and hope that the bearing is then properly adjusted.


Why would a tire be for trainer use *only*?

Turbo trainers are notorious for quickly wearing out tires. Trainer tires are therefore made of a hard wearing compound. However, this compound may not provide enough traction for safe cycling.

Traction is immensely important as it is usually the limiting factor to the maximum speed in curves. If one's rear wheel slides away while cornering recovery is usually not possible.

See also the related question: What kind of tire should I purchase for use on a bike trainer?


Who has information on this Fondriest Bike we found? Any good?

Brifters, lugged steel frame, flat pedals, single pivot brakes - I'll go with a late 80s bike or early 90s, but the brifters are probably retrofitted.

The wheels look relatively new.

Looks like a loverly bike and would be a great ride.

I note there is no rust evident anywhere, and its in very tidy overall condition.  So its been well stored and cared for.

The company is Italian, and their current website is http://www.fondriestbici.com/


Start by checking that the axle is clamped firmly in place. The connectors are part of the axle assembly and shouldn't be able to turn with the hub unless the axle is loose.

Note that the comment above about having the connections on the right hand side of the hub applies to older versions of the SON28. The newest versions (the 2015 40/48-hole tandem hubs as well as the 2012 and later versions with the smaller flange permit the connections to be on either side, http://www.nabendynamo.de/produkte/pdf/english/son282013e.pdf).


Mechanic and top rider's bike on right side of team car - why?

Yes, the idea is to have the quickest bike change possible for the person it matters most for.

With the bike attached on the same side as the mechanic's, he just opens his door, turns, and grabs the bike. For any other bike, he either has to go around the car, or even remove another bike before getting to the one he needs.

As for the obvious followup question (why is the mechanic on the right-hand side of the car?):

In case of mechanical trouble, riders and their support cars should stop on the right side of the road. That makes it easier for the rest of the race and other vehicles to avoid the obstacle. (This was actually part of the problem for Richie Porte and his controversial wheel change at the 2015 Giro d'Italia.) Of course, if there is a crash, the support cars will stop behind the crashed rider(s) to protect them from traffic.


Looking for a waterproof electrical bicycle, is there such thing as ip68 for electrical bicycle?

None of the name brand e-Bike motor manufacturers makes a motor intended for use in a bicycle that is also rated for continuous immersion in water.  (IP67 is a rating that it works when completely underwater, not that it is rain resistant....)
Some manufacturers do claim an IP65/6 splash resistance rating, particularly for hub motors.
Mid-drive motors are a little trickier since they are just a component that gets integrated into a frame by the builder and the manufacturer doesn't necessarily control the final product you get.  None of the three big brand names in pedelec mid-drives claim a specific IP rating for just the motor unit.  However, they have certainly all proven fine to ride in the rain in practical experience!  (Best to not leave parked outside in the rain with water pooling on components though.)


An angle grinder with metal cutting disk (or abrasive disk) will remove a U-lock in about 30 seconds. It is shocking how easy it is to cut through the shank. The one consolation is that it does make a lot of noise and a lot of sparks (and requires either a power cord or an expensive battery grinder), otherwise more thieves would be using them. If you do not have access to an angle grinder (and don't want to stop by your local bike shop, auto mechanic, or police station, all of whom will undoubtedly have one), then a hacksaw with a new blade  (or two) will eventually cut through, although it may take up to half an hour of vigorous sawing.
You should be able to bring over most of your previous components. However, be aware that bottom bracket sizes/types have changed considerably, the caliper distance (reach) and mounting style of brakes have changed, and there are peculiarities to seat tube and front forks based on country and year. Thus, unless you are replacing an early 1990s Italian road frame with an early 1990s Italian road frame (for example), you may find limited component capability. Pedals for almost all  recent bikes (except some cheap BSOs and children's bikes) are standardized thread so those will come over fine.
Yes, dented frames are dangerous -- especially aluminium and carbon fiber as their failure modes can be quite dramatic. Steel frames tend to fail more slowly (and can be re-welded).

tl;dr: Things that you can bring over (in general): Handlebars, brifters, seat, pedals, crankset, seat, front and rear derailleurs (with caveats).

Things you might not be able to bring over (unless your bike is the same era/style): bottom bracket, steerer/stem, seat stem, brakes, forks.


Reason why bike scratched up in this location under crankset

My guess is that this was caused by chain suck. This is a problem where the chain doesn't roll off the bottom of the chainring as readily as it should, and the chainring draws it up toward the chainstay. It can get wedged between the chainring and chainstay, and take off paint in exactly this way.

This can be caused by worn cogs, a worn chain, a too-long chain, or too little tension in the rear derailleur holding the chain taut.


Stiff but short daily commute leading to "heavy" legs

How hard do you ride? If you ride hard and in hard gears it could be that your legs are accumulating fatigue and simply don’t have enough time to recover from one day to the next even though it’s only 3km. It’s made worse because you don’t have an easy start to warm up.

Even pro riders don’t do hard training every day, most of the training is spent at an easy “endurance” pace.

Take it easy (at least every second day or so) to allow your legs to recover and get stronger. Get easier gears if you don’t have them.


I tried both techniques proposed here, but to no avail (I might have damaged the BB with the hammering).

The LBS had the tool for the job - experience. The guys put the wrench in a vice, calculated the direction to unscrew carefully, then put the frame on and just unscrewed the damn thing. The frame was providing large leverage.


Vintage Sealed Hub Maintenance Questions

First, don't hammer anything, yet.

Non-drive side looks like a sealed cartridge bearing. On the drive side you have a freewheel unit that screws on. You'll need to get that off before proceeding further I believe. The drive side bearing is located at the inboard side of the freewheel, which is why you are not seeing a seal.

Park Tool has a pretty good video on freewheel removal that helps you find the right tool for your particular freewheel.

Next steps depends on what you want to do, either re-grease or replace the bearings. Either way you can find YouTube video how-tos. Try this and this from Global Cycling Network.

If you you want to remove the seals on the cartridge bearings to re-grease, the seal can be very carefully prised off with a thin sharp object such as a box cutter blade.


I bought a bmx with a 20x2.35 inch tyres on them, can i buy and put a 20x2.4 inch tyre on them without changing the rim and inner tube?

Look at the clearance between your existing tires and frame/fork. 0.05" is about 1.3 mm, so it means about 0.7 mm at each side. This is hardly noticeable difference. If your tires are not already dangerously close to rubbing your frame/fork, neither are the 2.4" tires.

Be aware, however, that manufacturer's measure of a tire is an estimate, and actual tire width depends on the rim width and other factors. Tires marked as 2.4" may in fact be narrower than older 2.35".

Inner tubes are flexible and can stand at least 2× to 3× variation in width. In your case, the difference is about 2%, so you'll be fine.

Similar goes with the rims. There are limits on how wide a tire makes sense to install on a rim of given width, but 2% of difference is just below error margin.


What is a good way to learn how to ride a bike on rollers?

how do you learn how to ride on rollers?

Believe you can do it.
Do it!
Do it in a doorway.
Practice

  How long does it take you to get the hang of it?

Took me about 30 min. on a set of plastic parabolic rollers before I felt comfortable enough to take the rollers out of the doorway and just be next to a wall.

  are almost guaranteed to fall off a couple of times before you get it nailed?

No... and maybe. Depends on your comfort level of being on a bicycle, hand eye coordination, and what kind of rollers you are riding on. I have yet to ride off of or fall off of my parabolic rollers. I had spent a lot of time on a bike before ever getting on the rollers the first time and my balance is fairly good.

If I had learned on a pair of cylindrical rollers, I think I would have ridden off or crashed at least a few times before really getting the hang of it. Not looking down and getting the wheels spinning makes a big difference. The hardest part is getting going. I found it fairly easy to start out by holding on to the doorway and having my bike in a middle gear so I didn't have to shift when starting out. I would then have one hand on the top of my handlebars and start pedaling. Focusing on getting my wheels spinning, I would slowly let go of the doorway but keep my hand there so I could grab the doorway when I wanted. Once I was starting to get comfortable, I slowly let go of the doorway and put both hands on the handlebars. Success!!

http://www.flickr.com/photos/bikeride/250957762/