Front derailleur cable suddenly very slack (no shifting), not sure what's caused it

Most likely cause is that the front derailleur cable simply slipped through the pinch bolt. The derailleur cage has to put significant force on the chain when shifting to the large chainring which can overcome the clamping force on the cable.

Another cause of shift cable becoming slack is the housing popping out of a housing cable stop on the frame. As you describe the shifting feeling progressively looser my bet is on the cable slipping. The cable could also have snapped but that tends to happen when shifting and is sudden and obvious.

Couple of things to check: Hold the cable taught and verify that the shifter is pulling and releasing it. Manipulate the derailleur by hand a verify that it will swing through its proper range.

Re-secure the cable and re-adjust the derailleur and you should be OK. It's a good idea to run thorough a setup procedure as front derailleur adjustment can be tricky. Park Tool has a good web page and video with step-step instructions.

https://www.parktool.com/blog/repair-help/front-derailleur-adjustment


Pressure gauge on my pump stuck at one value, what is wrong?

Considering it's supposed to be sealed you can get quite a lot of muck in a pressure gauge -- maybe dirt collected on the valve.  That's probably what's causing your gauge to stick. The cause of the initial head jamming may have been similar.

I lost a tyre to a blowout when the gauge on my Road Morph was very reluctant to go up.  I took the gauge to bits (one rather subtle screw/cap which also allows me to set the zero point) and cleaned the spring, the piston and the scale that shows through the window. I didn't oil/grease anything, as the piston felt like it hadn't been greased to start with. It seems to move freely now.


Reginas and Prestas are really close in size, they can easily be interchanged. If you do find that it rattles in the larger hole on mixed surfaces, you can always use the threaded Presta nut, just don't crank it down too much. The Regina valve also has a metal seat, so before using the Presta, I would get a bit of emery cloth and make sure that there are no burrs on the inside of the valve hole - Presta tubes have a double rubber seat, so they are more fragile.


As a rough rule of thumb, those ratios are approximately right but there is quite a bit of individual variation and there will be more individual variation in the mean maximal power to FTP ratio at shorter durations than at longer ones.

If we consider a mean maximal power curve, a plot of the maximal power one is capable of sustaining plotted against duration, it is generally pretty flat from 8 minutes out to many hours. It's not of course totally flat and there are various individual factors that influence the shape of the curve. The slope is greater at the shorter duration, and it has more individual variability there.

This example curve taken from Jack Mott's website shows (note time is on a log axis):

Now while this is the general shape of a MMP curve, there is individual variability and I chose this image as it gives some clues as to why, namely the contribution of the various metabolic energy systems that supply the energy varies depending upon the duration of a maximal effort, and also upon the unique physiological characteristics of the individual.

So while long duration efforts are dominantly fuelled by aerobic metabolism, during shorter maximal efforts there is a greater contribution to the energy demand by anaerobic metabolism, and anaerobic capacity is highly individually variable.

As a result, the ratio of short duration power capability to FTP can vary quite a bit between individuals, while the ratio of long duration power capability to FTP will be less variable.


Is there a hub gear that can be disengaged?

Old, plain, one-gear Velosteel-like hubs had this feature thanks to using rollers instead of cogs, but I suppose it does not meet your expectations.

If you REALLY need this feature you can modify Shimano Nexus 3 to obtain what you want by removing four cogs from part no 4 shownhere. You will lose 1st gear, rest will work as before.


Based on your symptom of the 'rear wheel being versatile" which I take to mean a wobble related to loose bearing adjustment in the hub. If the mechanic completed a complete hub overhaul the axel, bearings and cone nuts would've been removed, examined, replaced if needed and then put back together packed with new grease and adjusted properly so that the wobble was gone.  None of this takes place where the "clicking" is generated. However I often try to get some lubrication dripped into the freehub where the pawls engage to create the drive force of the sprocket. A combination of lubricant and a tighter bearing system can sometimes quiet the pawls. Other times the sound is more distinct as the liquid lubricant loosens the old grease and the pawls move more freely and "snap" through their range of motion.  Obviously there may be something wrong if you're experiencing a slipping sensation or if when you begin pedalling again after coasting there's a sensation of the cranks free spinning and a delay in the normal resistance to pedalling.


Should I eat breakfast before or after morning ride?

I think that is question can at least be partially answered by whether or not you can tolerate food in your stomach.  While having a big heavy meal would probably be bad, having something in there, plus doing some refueling along the ride will help you keep from bonking and also make sure you are not running on a deficit for the rest of your day.

I find that if I have a light breakfast and then add to that energy gels about every 45 minutes I am pretty good.  My riding buddy, on the other hand, eats a McDonalds McMuffin and hash browns which would make an explosive exit if they were in my stomach.


What should I look for when buying a used bicycle?

Issues of where to find a bike have been answered pretty thoroughly here, including the standard disclaimers of making sure a bike isn't stolen before purchasing.

On advice for how to see how ride-worthy a bike is:

Definitely take a look at the bike before buying. Give it a quick once-over for general wear or use. If the bike looks like it hasn't been maintained well, it will probably show. This doesn't mean it isn't a good bike, but you want the best you can get.

If you don't see any obvious signs of mis-use, check each system more thoroughly.

Keep in mind that this is not an exhaustive list, and that you will find problems with any bike if you look closely enough. It doesn't automatically mean you should look for a different bike either. What's important is whether the problems you find are evidence of deeper issues, or if they will cause problems in the future. Many issues can be fixed at home with a little effort, but it's still better to be aware of anything before you buy a bike. These small fixes can also add up if you're looking for something cheap. I'll try to point out bigger problems that you want to avoid.

History: Simply ask if there have been any problems with the bike. Has it been in an accident? was it rebuild? does it pull the left? How long has the seller owned it, how much have they used it, etc.

General: Does anything squeak or make unusual sounds? Can you stand comfortably over the frame with your feet flat on the ground? Does the bike still have reflectors in the front and back, the wheels, and pedals? Has the bike been registered previously, and can the owner produce the paperwork to transfer the registration? Do the parts have a well-greased and smooth feel to them?

Wheels: Look for wear on the tire tread. Is there any damage to the side walls of either tire? What kind of conditions are the inner tubes in? As how many flat repairs each wheel has had, and if either tire leaks air significantly.

Make sure the wheels attach firmly to the frame, and that the wheels remain secure when you torque them relative to the axle. (You don't want any 'play' in the wheels, as this may be a sign of one of those deeper problems with a loose cassette or worn ball bearings.) How are the spokes? Do they have relatively even tension on them and look like they're in good shape?

Spin the wheel on the bike, and look down the thread for any wobbling or mis-alignment. If they do, the wheels could probably use a re-alignment.

Brakes: Check the brake pads for wear. Will then need to be replaced soon? Are they aligned for proper contact with the braking surface? Do they engage quickly when the brakes are applied?

Cables: Check for any frayed ends or rusted sections. Are the cable guides still in place and preventing unnecessary wear across surfaces? Do the cables have end-caps on them to prevent future fraying?

Pedals: Do the pedals appear to have struck the ground before or they otherwise in good shape. Torque the pedal arms against the axle to see if there is any looseness. Spin the pedals by hand to ensure they rotate smoothly, but aren't too loose or tight. Also spin the pedal crankshaft to look for the same types of things. As with the wheels, being overly tight or loose at the axle may be signs of bigger problems.

Gears and Chain: Visually inspect the gears for any wear (each tooth should be symmetrically shaped, not wave-shaped). Is each gear parallel to each other on the cassette? How does the chain look? Has it been well maintained and lubricated. This is probably the only part where you would need any equipment to check your bike, but a chain-wear tool would be useful to check for a stretched chain. If you don't have such a tool handy, the aforementioned wave-shaped gear teeth are evidence of a stretched chain in need of replacement. Wave-shaped gear teeth mean the gears should be replaced also (not usually a good sign). Does the gear switching mechanism allow you to reach the highest and lowest gear, and does it move well?

Handlebars: How are the handlebars positioned relative to the seat. Are they within comfortable reach? Can you reach the brakes quickly. Are the handlebars in line with the wheel? Is the tape worn and cracked, or does it look like you will still get some mileage out of it. Do the handlebars turn smoothly in the frame with the wheel, or is there any tightness or looseness?

Seat and Post: How does the seat feel? can it be adjusted to a comfortable height and does it stay in place well. Quick-release adjustments can be a huge plus here.

Frame: How does the frame look. Is it still in line with itself or has it been torqued or bent. Are there any signs of cracks or dents? Problems with the frame tend to increase in severity with use and affect biking efficiency as the frame degrades. Some light damage might be okay here, but be aware that a damaged frame can quickly become unusable.

Ride the bike: Ride the bike for a short distance, switch through the full range of gears. Pedal hard, brake hard with both brakes (but don't let yourself fly over the handlebars), and turn a few times. How does the bike feel? This includes how the bike actually performs, and how well it feels for you specifically. Is the bike comfortable for you. If not, can it be adjusted so that it is?

Take someone with you when looking a the bike. You never know who you might come across through Craigslist, and two sets of eyes may notice more than just one.

Best of luck


Upgrading wheels on a vintage Peugeot Frame

You're on the right track! My answer will be long, but I have a lot to say, so here we go!

Firstly, lets deal with your dropout spacing - there are two solutions I have used on my old steel road bikes. The first is to buy a 126mm freewheel hub which can be built up with sleek rims and will take a high quality 6 or 7 speed freewheel. The two manufacturers that come to mind are Velo Orange and Paul Components - both are very high quality, but the VO hub costs $75 and the Paul hub costs $184. They both use sealed bearings and are both very nice to look at (with their high flanges and windows.) The benefits of using a 126mm hub is you avoid having to respace your frame, but the drawback is that you're wedded to freewheels which, if you change out gear clusters frequently, can be troublesome.

(Random note: try to not lose or break the rear quick release for a 126mm hub. It is a HUGE pain to find another one on short notice as most QRs have threading for a 130mm hub, minimum. Plus, the threads are rolled, not cut, so you can't just run a die over a skewer and make it shorter!)

The second option is to swage out your stays to accept 130mm or 135mm rear hubs. There is an excellent thread here which will give you more info. I successfully respaced my 90s' Bridgestone from 126mm to 135mm so that I can run mountain hubs with cassettes. You could just try to squeeze a 130mm hub into your frame, but in my experience it is hard to close your QR enough to force the dropouts comfortably flush against the hubs locknuts (and this isn't a good thing for wheel bearings, especially cartridge bearings! It would be more of an issue as the dropouts get splayed wider. More and more bikes are now made with dropout spacing at 132.5mm so that you can go up to 135mm or down to 130mm easily.)

Being an older steel bike, it may use 27" wheels. 27" wheels have a BSD of 630mm, while 700c wheels have a BSD of 622mm. You will want to upgrade to 700c wheels because tire and rim availability makes it practically necessary (i.e. there aren't many mfgs of 27" rims/tires anymore!) The difference isn't important in terms of frame size and clearance, though you may run into problems with your brakes if they don't reach far enough to contact the smaller 700c rims. Brake reach is measured from the brake bolt hole diagonally down to the center of the rim braking surface. On cheap brakes with no vertical pad adjustment the pads would just eat into the tire's sidewall. Either long-reach brakes or a drop-bolt will solve this problem. (If you do replace your calipers, make sure you get nutted brakes or learn how to adapt a frame to accept recessed mounting bolts.)

Your bike has caliper brakes, but I want to add a bit of info regarding bikes with cantilevers as I've had to slog through this mess several times before. Since canti studs are brazed to a frame with a rim diameter in mind, switching from 27" to 700c rims will pull the braking surface down by 4mm which, when using brakes with limited adjustability, means you have to swap in some with lots of vertical and horizontal pad movement. Since canti stud placement has only recently been standardized, this makes upgrading old touring frames a crapshoot as brake availability is limited. One measure I took on a troublesome 1981 Miyata 1000 was to run caliper brakes and leave the canti studs alone altogether. (Another issue with upgrading wheels on an older canti-brake bike is the distance between the front posts. See this thread for more info.) ((A more final approach would be to braze on a new set of cantilever studs, but this is hardly a novice project.))

Finally, in choosing drivetrain parts that will be consistent and compatible, I don't think you'll have an issue. Friction shifters are compatible with (mostly) everything (good choice.) As far as chain width goes, with a new Shimano-compatible hub you'll be able to fit an 8 or 9 speed cassette - a 7 speed cassette will likely need a spacer to fit properly.

Your rear derailleur will have to be reasonably modern, but I haven't had any issues with running 9 speeds under an 8 speed derailleur. In general, it is easier to use 9 speed hardware on 7 or 8 speed cassettes than to use 7 speed hardware on 9 speed cassettes. Ideally, chain width should correspond with your rear cassette (ideally.) The only concern would be if the crankset and chainrings were designed to run 5 or 6 speeds originally. If the distance between the chainrings is too great the chain can slip between them, but I've never seen it happen, even on franken-bikes with mismatched drivetrains. Here is a great Sheldon Brown article about gearing.

Hope this helps!


Dahon Speed Uno. Main frame hard to fold

The main frame hinge is made to have adjustable tension. A little lubrication on moving parts is a good thing.
The manual Dahon publishes is a one-size-fits-all manual with instructions for adjusting a variety of frame hinges starting on page 14.
Here is a review of the Dahon Speed Uno that goes into great detail on how to operate the bicycle along with videos of folding and unfolding.


First double check that it's not a simple case of it just being tight, which is actually pretty common. Remove the bolt completely and gently wedge it open just a little bit with a screwdriver, and see if it will fit on then. Do not force it - you're checking to see if it fits correctly albeit a bit snugly.

If that doesn't work, and/or if it's just clearly the wrong size completely, you need to measure both the clamp you've got and the outside diameter of the seat tube. Ideally use a caliper. You could almost get away with just using a ruler to see what size the frame is actually "trying to be", but the problem is that frames do exist just .5mm larger than 34.9, even though 34.9 (aka 35mm) is much more common.

There are some weird, semi-proprietary diameters in the 35-36mm range that have given rise to clamps like this and this. 36.4mm is also a standard size, but as far as I've observed it's not common for carbon road bikes.


If you spin the wheel by hand with the bike off the ground, then side-to-side wobble is also called "out of true" and is caused by spoke tension, or an impact while riding.  Wheel going badly out of true on final tightening

On the other hand, if you hold the non-spinning rim in your hand and move it left/right while mounted in the bike, there should be no play discernible or visible at the axle.  If you feel motion sideways, then its bearings malajusted. How do I know if my cone/cap/bearings need to be adjusted?

A wheel can have both, or ideally neither, or either.


Seating the rear derailleur cable housing

Set the shifter to the slackest/highest position.
With the bike's rear wheel off the ground, put one hand on the body of the rear derailleur and push while turning the cranks with the other hand.
Push the derailleur until it shifts all the way up to the biggest cog and let go of the cranks and the derailleur.
Put the ferrule in the housing stop.
Turn the cranks a few times to let the rear derailleur return to the smallest cog.


You have to consider compatibility between the shifter/brake lever units and:

Rear derailleur
Front derailleur
Brake caliper

Rear derailleur should be fine, Shimano uses the same cable pull ratio for everything 9 speed an below.

Front derailleur is probably OK, although I'm not familiar with Shimano's schemes for front derailleur cable pull ratio.

Brakes can be problematic is there is generally a difference between the leverage ratio in the levers and calipers for 'road' style U-brakes and MTB V-brakes.

Even if you can work out the compatibility issues, the cost of replacing the bars and shifters can be significant compared to the purchase cost of the bike (especially at the Tourney level). Sometimes selling the bike and purchasing one more suitable for your needs is the better way to go.


Chain repeatedly tries to click into place without gear change

Since this occurs every 10 seconds, this leads to believe that you have a frozen link in your chain or a defective link in your chain.

If it were a cable or dérailleur adjustment, it would occur all the time while pedalling. The pause leads me to think that the chain is fine when continuing around the big sprockets in the front, but when it gets to the cassette and dérailleur, the size of the cogs and the angle at which the chain is being bent causes the stiff link to manifest itself.

As something you can fix at home (in the event of a stiff link), lube the chain with any bicycle lube.

If that doesn't help it, you probably have a defective link and the bicycle should be brought to the local bike shop.

Best of luck!


Bike brake cables popping out of brake handles

It's hard to tell completely, but it looks as though the cable isn't under proper tension.  The housing end shouldn't be floating outside the adjuster barrel like so.  It's possible they were loose before and assuming an amazing "power grab" during teh crash they may stretched or slipped a bit (at the other end of cable).  Adjust the brakes.


Do you need to lubricate gears after cleaning gears and chain?

I always wash off the degreaser, lube the chain, and then run it through all gears to get a bit of lube worked into everything. Don't need to lube the gears specifically.

I think the key is to be sure to wash off all traces of the degreaser. Last thing you need is residual cleaner gunking stuff up.


What do I need to know when replacing my cassette?

The 14/28 is the number of teeth on the smallest and largest cog of the cassette. From your description you want to make at least the second number smaller, possibly the first number.

As long as your replacement says that it's Shimano compatible (and 7 speed), you should be fine. Count the teeth on the cog that has the most teeth that you actually use...make sure the new one has at least this many teeth. I would go a few extra teeth but my legs get fatigued now and again and I just go into pleasure-commute mode. My off the cuff recommendation would be to look for a 13-26 (Amazon has these for less than $25 bucks). I'd say the 13-23 would be too much of a jump.

More information on the topic from the oracle Sheldon Brown: http://sheldonbrown.com/k7-7.shtml

Depending on how many teeth there are on the most largest cog, you may need to take a link or two out of your chain. Replace the cassette first and see (or better yet, take this opportunity to replace your chain as well).

Happy Riding.


Does hub diameter or hub size have a notice able effect on the aerodynamic performance of a wheel set?

There would be a measurable decrease in drag from removing external dérailleurs and gearing, however I would guess that the power loss through an internally geared hub would make such a setup slower rather than faster.

(I have no sources for this)


Jamis Commuter 4 conversion to derailleur geared

I don't see any holes designed for a derailleur hanger. You should be able to use this type though. It clamps into the horizontal dropout. I've heard them called claw hangers. Don't know if there's a better name for them.


There are many tire options available.

The Schwalbe Marathon Plus in. 700x35c, or the Specialized Armadillo tires in the same size will work for you needs.

The bike has other issues, though, including the mentioned missing brake.

It also appears to be small for someone 6 foot tall.

I would recommend having a good mechanic thoroughly check it over before riding it.


Good question - I went down the same path (MTB -> road bike) and was worried about having to be super gentle. But actually, a road bike is surprisingly strong provided forces are applied in the right direction. Riding off curbs or over bumpy surfaces shouldn't cause a problem, but I wouldn't suggest doing drops. Similarily provided your bike isn't a super lightweight frame (and it sounds like it isn't) fitting a rack will probably be okay (especially if the frame has mounts for them).

A lot of the pros on the Tour de France used their standard road bikes on the cobbled stages just with special tyres, and those stages were very bumpy. And the teams that used dedicated Paris-Roubaix style bikes mainly did so for comfort and speed, not strength.

It's when you start applying forces to the bikes in ways that weren't intended that you are likely to damage it - i.e. riding into things, jumps or crashing. That's where the extra durability of a mountain bike comes in. It also depends on your weight - without being rude, if you're a big rider simple physics means you are going to stress the bike more.

If you do do damage it may not be easy to see. Especially small cracks may be very had to spot, although if they get big they will be pretty obvious. I certainly wouldn't recommend assuming that just because you can't see problems there aren't any there - you really don't want your fork to fail at the crown which could cause a very serious accident.

If you are planning to ride your road bike off road a significant amount you might be better off with a cyclo cross bike. It will be a little bit heavier but stronger and more capable of dealing with crashes, but more importantly it will enable you to fit much wider tyres, and gives much better mud clearance. Many cyclocross bikes have rack mounts on them as well, and the geometry is tweaked to make them more comfortable to ride off road.

It's just my experience but as a mountain biker, I feel much more comfortable riding a cyclo cross bike - either on or off road - than I do a dedicated road bike, probably because the handling is better (for me).


That is unlikely. The inside of a frame is machined/molded to a specific size for the seat post. An integrated post is not finished internally. Also, it is unlikely that the internal and external diameters of the post/frame/clamp would match well enough to be ridden safely.

Seat post fitting is a zero tolerance game, and they are dimension-ed to the tenth om millimeters. You would have to be beyond lucky for that to work out.


Picking bottom bracket and chain set for older mtb frame

There are a few of ways to find out what will fit:

Research websites like Bikepedia and Norco.com and check the original spec. You've possibly done this already and found it's of little help.
Pull the cranks off and remove the BB length and diameter will be printed on it. You're looking to take it off anyway.
Remove everything and measure, this will be most complicated and a last resort.

They're your three options, but with a bit of googling to confirm it's easy to find threads dealing with this. Essentially most North American mtbs of this age run a 68/73mm English threaded BB and a 47.5 or 50mm chain line. 2.5mm won't be a significant difference however.

As you are replacing crank and BB you only need to match what you buy, so if you get a square taper BB you need a square taper crank and so forth. The crank determines spindle length, not the frame. Shimano Hollowtech II cranks come with an external BB so always an easy option.


Exceeding speed limit with Ebike, is battery affected?

Actually, when you are running the motor near the top of the speed limiter, it's the happiest and most likely drawing the least current. If you had a CycleAnalyst or other amp gauge, you'd see it reduce current as it reaches the point where the controller is turning it off to reduce the speed. The motor will be cutting in and out due to the limiter, but will otherwise be just fine with this regimen as it's effectively operating on a reduced duty cycle at full speed - optimal conditions. This is quite unlike internal combustion engines which don't like to be operated at the highest end of their RPMs.

Furthermore, when you're running at full speed, air cooling to the controller, battery, and the motor is at its maximum, so they're at their happiest thermally.

The hardest thing on an electric motor, controller, and battery is starting up from a dead stop and going slowly up a hill. This is when the motor requires the most torque and thus draws the most amps - but also has the least airflow - which means everything heats  up and potentially reduces their life.

As I noted in my comments, though, the best way to extend the life of your (presumably) lithium batteries is to not drain them to 0% and to also not charge them to 100% -- but for the latter, you'll need a charger with an 80% or 90% cutoff. These are sold on the after-market. With careful dis/charging practice you can extend the number of charge cycles from 300 cycles to 900 or more.


Mechanical disc brakes lacking stopping power

I have TRP spyres and while I find they perform better than BB7's when properly adjusted, they are very sensitive to adjustment. They have a very narrow range between rubbing the disk and too far away for proper braking. You may have to put up with a slight bit of rub to get proper braking performance.

While they are dual actuated[1] like hydraulic disk brakes, they are not self-adjusting. This means that as the pads wear the brakes need to be adjusted to compensate for the wear; it does not take much for these brakes to get out of adjustment.

You will need a 3mm hex wrench to do the adjustment and if you are going to stick with this bike, I recommend that you learn to do it yourself. You need to adjust both brake pads on a regular basis. I've gotten in the habit of checking my brakes before every ride. They don't need adjusting every ride, but it something to watch.

If that seems like more than you want to deal with, your options are to either switch to BB7's or a more expensive road hydraulic setup. BB7's work well and aren't nearly as sensitive being adjusted properly, but since they only have a single actuator they are not as easy to modulate. For a road bike that is much less of an issue than for a bike meant to function well on dirt. BB7's do require regular adjustment, but in my experience not nearly as much as the Spyre's. They also do not require a tool to do the adjustment.

The last thing to check is that your TRP's are the proper model. Mechanical disk brakes often come in both Road and Mountain models that work with different pull ratios. Since these brakes were on the bike to begin with it's unlikely, but it is something to check. Look online at both models and look at the length of arm that moves the brake pads to determine if you have a road or mtb version.

[1]- dual activation means both pads move toward the disk, most other mechanical disk brakes have one fixed pad and one moving pad.


Which position adjustments maximize the use of the glutes in a road bike?

Cyclists often become quad dominant in their movement patterns, where the quads are preferred over other muscle groups, such as glutes, for a task where both can be involved. This can start to weaken and de-conditioning of glute muscles, causing the body to further prefer quad dominate movement patterns (i.e., reinforcement).  A quick test can be to do a squat and then stand, if you find yourself driving from the balls of your feet rather than evenly through your heels and balls of your feet, you are likely favoring your quads over your glutes (or you could have a short torso and long femurs - no test is perfect).

If you have become quad dominant simply changing your position may not be enough to get your glutes firing effectively as you may have: A) de-conditioned the muscle; B) trained your neural pathways to de-emphasize glute recruitment in favour of quad  recruitment; and C) if this pattern has gone long enough lost flexibility which could further inhibit movement patterns emphasizing glutes. As such may also find the glutes only fire when working very hard because the nerve impulse is finally strong enough to get the muscle to contact effectively.

Assuming you can fire your glutes well, a saddle position where you can roll your hips forward slightly allows the glutes to be recruited easier through the bottom of the pedal stroke. Saddles with a swoop profile (i.e., high tail) facilities this position. I also personally find if I focus on supporting my upper body weight from the front of the hip this seems to further encourage the glutes to engage (rather than rolling your mid to lower back which rolls the top of hips backwards). To set up these types of saddles, set a level on the middle third of the saddle and adjust until horizontal, this should be a good starting place, overall the saddle will appear somewhat angled down, but this is a visual trick caused by the swooping profile. Some may find this type of position difficult if they lack mobility in their thoracic region of the back or core strength (e.g., constant slouching posture can lead to a reduce thoracic range of motion making this type of position difficult).

If you are still having trouble, you may also need to strengthen your glutes and train your ability to fire them. Squats, bridges, lunges are some basic exercises that can help, but they require good movement patterns to fire the correct muscles, for example you can compensate in a bridge by recruiting your hamstrings instead of your glutes. As such, it can help to get a trainer to make sure you are doing the exercises properly, otherwise you may simply reinforce compensatory movement patterns in order to get the “task” done.

Finally, improving glute strength will also help reduce repetitive stress injuries as they also are important component of hip stabilization (e.g., gluteus medius are often weak in cyclists - the link has a good exercise for this). In terms of power, I found getting my glutes to fire properly again after years of poor posture was worth about a 20-30 watt advantage on my FTP.

Reference

This passage from "Bike Fit" by Phil Burt (lead physiotherapist for British Cycling and a consultant physio for Team Sky) describes pelvis position and the impact of thoracic mobility.

  POSTURE

  Posture is the maintenance of a certain body position and requires appropriate joint mobility, joint/muscle coordination and muscular endurance.  Limits in any of these elements can result in postural irregularities.  Good posture on the bike required good flexibility through the hamstrings and the glutei muscles:  this allows the pelvis to roll forward, keeping the back in a straight position while reaching the handlebars.

  One major factor limiting the back's ability to remain relatively straight while on a bicycle is thoracic immobility: lack of movement in the middle of the spine normally results in the spine flexing too much.  Excessive spinal flexion while on a bicycle will limit breathing and compromise your ability to stability your spine for torque production to the pedals

  [emphasis added]


This topic is really poorly understood. Anyone who ever who tells you it's fine to just round up or round off when choosing spoke lengths hasn't been through the disaster scenarios that can be caused by it, or perhaps doesn't remember because the experience is too painful and embarrassing. Rounding up can cause you to run out of threaded length before the spokes are fully tensioned. Always round down unless you can test and measure the spokes in question before building to avoid running out of threaded length or poking the tube. If you have to order spokes, just round down. If your calculated optimal length is accurate (and there's no reason it shouldn't be) and you must round down to the next even number from there (as in the 292 in your example), nothing meaningful will ever be lost in terms of durability from that extra 1.99mm max.
What gets overlooked in this discussion is that there are whole brands/models of spoke, or spoke/nipple combinations, that offer zero ability for the spoke to protrude past the top of the nipple. They don't have the threaded length to do it. So rounding up walks you right into the failure situation of running out of thread and having to either start over or accept an untrueable wheel with bad tension. Various Wheelsmith bags I've used, for example, have been like this, with Wheelsmith nipples.
Contemporary DT Champions and Competitions, the most commonly encountered premium spokes, avoid this occurrence by having some superfluous/generous threaded length. Some other spoke brands and models do not, and give you no leeway for the spoke to be long. And single wall builds naturally have no such leeway.
Some point out that having aluminum nipples miss more than 1mm or so of engagement introduces some risk of the nipple breaking. That's probably true and I recommend shooting for the best possible thread engagement on aluminum nipples, which for practical purposes on conventional nipples is between the base of the screwdriver slot and the top. However, you'll never know if that's what caused it, because al nipples break anyway, especially for 2mm spoke ends. (Al nipples for 1.8s are far less prone to breaking because of the extra material.)
Your calculation must be accurate. You don't want to miss more thread engagement than around 2mm from perfect. Never use a calculator where you can't verify that the math it's doing is the pure classic spoke length formula. Some calculators try to invisibly factor in estimates of spoke stretch and rim compression, which you should do manually based on the parts you're using. (Spoke gauges differ in stretch, the amount of tension also causes it to differ, and the stoutness/cross-sectional area of rims make them differ in compression.) Because it's an Excel spreadsheet and all its formulas are right out in the open, Spocalc is my preference. And always measure the hub and rim yourself. It seems pedantic, but I promise that if you build enough wheels, or are ever working for a wheel producer and are tasked with doing spoke calculations and there's never time to do test runs of anything (this was my situation that taught me good spoke calculation habits), you'll find all this necessary to have consistently good results.
If you have to order the hub/rim along with the spokes (particularly the rim, because manufacturer list measurements for hubs are usually very accurate), just take vendor/manufacturer listed measurements on faith for calculation purposes, but measure yourself once you do have everything to make sure what you're about to do is going to work. Second-guess published ERDs early and often.
Wheelbuilding texts almost never remember to tell you that longer length nipples usually have more threads, and you need to compensate for this to avoid bottoming out the threads on the spoke. Most handbuilt wheels are done with 12mm nipples, but if you ever use 14s or especially 16s, you'll find the rim's ERD is effectively a few millimeters smaller. Or, in other words, ERD is usually calculated as the diameter of the circle formed by the tip of the spokes in a state of optimal thread engagement. Usually that's synonymous with the tip of the spoke being just about flush with the top of the nipple, somewhere between the bottom of the screwdriver slot and the top. 12mm nipples can all handle that, but most of the time if you thread an aftermarket/handbuilding-worthy/premium (however you want to say it) spoke into a 16, you'll find it runs out of thread and bottoms out before it reaches the top.
If you do need to round up, or insist on getting full thread engagement, always test it out first by taking a nipple and spoke that you're about to use and see how far the nipple screws on before it bottoms out, and then measure the amount of protruding spoke you have to work with to make sure it will be acceptable with whatever your calculated length was. Also make sure the rim's depth is such that it won't cause spoke to protrude up and poke the rim strip/tube. If the spoke meets these criteria it's fine, but it can't just be assumed that it will until you test. Do that test on enough spokes and you'll see.


What is the actual width of a Panaracer Pasela tire?

I just got an email from Harris Cyclery, and they said the plain Paselas (no Tour Guard etc.) run "pretty true to width".  Didn't get any measurements from them, though, and i don't have any Paselas myself.  I use 28 mm Panaracer Rolly Poly tires, and will soon be getting a set of 28 mm Grand Bois Cerf.

Would be nice to have a webpage of true width measurements of various popular tires on various popular rims.


Will Shimano B01S brake pads work with m675 slx

B01S resin pads is one option you have for pads for this model of brake caliper.  If it is longer lasting metal compound pads you seek for the SLX brakes, Shiimano spec sheet lists the  F03C as the compatible metal pad.


Noise + vibration while back-pedalling. Should I be worried?

Your video shows that the problem resides in the position of the derailleur. The RD is much too close to the cassette. The jockey wheel almost touches the large sprocket.

Use the B-screw to move the upper jockey wheel further away from the sprockets.


Gates Carbon Drive single speed shows inconsistent tension

To my awareness, the Gates-ness won't introduce any factors here not present in other single ring, single cog bikes without chain tensioners, other than making it way more expensive to do any replacing of drivetrain parts that may wind up being needed.
One of the questions in this scenario is whether you have reason to suspect the increased tension spot was acquired in use, over time, or by violence, versus occurring immediately after wheel re-installation. Concentricity is never perfect; if the tight spot started after the belt tension was re-established either from the wheel being off or sliders being adjusted if applicable or anything else, it's likely that donking the wheel forward a bit will make things how they were, i.e. there will be a tightest spot that you just don't notice, which is how all bikes without sprung tensioners are.
If the "front pulley" (Gates speak for chainring) was damaged from impact, something like this can result. You'd likely be able to see it by backpedaling the bike while carefully observing it turn against a fixed reference point. They're stiff and need their dimensional precision, so you should probably replace it if you find significant problems. If the tight spot is always in the same spot in the crank rotation, it's not the rear cog unless the quotient of the front and back teeth count is a whole number. It can be then.
The last avenue is messing around with improving front concentricity by trying different spindle positions, especially if the cranks were removed and re-installed recently, or squirming the "front pulley" on the spider tabs, which is kind of the most likely cause and fix of the whole problem if other mechanical changes or a traumatic event didn't precede the issue. Barnett's is a good reference to read about procedure for the former and Sheldon the latter.


Replacing old brake blocks with modern pads

Those long "mountain bike" Kool-stops work fine on my modern skinny wheel road bike with side-pull calipers. If the modern Kool-stops fit (and don't see why not), I'm sure they will outperform those vintage looking ones - the contact area is much greater. I'd even bet the long contact patch results in less torque on the caliper arms, but I doubt it's an issue either way.

Those Kool-stops are nice, the mounting hardware allows fine adjustment of the plane of the brake surface. You're supposed to adjust them with a little toe-in (toe-out?) so the inevitable torque when applied straightens them out (we're talking a very small amount of inevitable torque twist - but the Kool-stops are designed to account for that). That little bend on the tip of the red side helps with the setup for that.

Take the bike in and ask the bike shop, but my guess is they'll work fine on 60s era calipers/skinny wheels.


How is chainstay length defined for frames with horizontal dropouts?

If I'm describing a complete bike, it's defined by wherever the center of cogs are at that time.

As we move into this bold world of full suspension mountain bikes with adjustable geometry, the ones with flip chips on the dropouts talk about the varying lengths of the chainstays.

Santa Cruz's description of their Megatower frame (emphasis mine)

  In order to make the Megatower stride confidently across the globe it has an enormous amount of clever adjustability hidden in its bones. A tidy and concealed flip chip in the lower-link adjusts bottom bracket height and changes progressivity of the rear suspension. A second, in the rear dropouts, allows for a 10mm fore-aft adjustment in chainstay length to dial in the rider's rearward weight distribution - either set for play or for stability. The flip chips are a robust mechanism for riders looking to tune their ride according to their needs without compromising reliability and durability. No wackadoo mousetraps and frail proprietary shocks here.

from: https://www.santacruzbicycles.com/en-US/megatower

So in the case of horizontal drop outs, I would provide the range of reasonable lengths, or measure to the center of the dropout and provide the available adjustment if I was describing only the frame.


I would recommend first checking on what Noah recommended: checking that the crank bolts are tightened down to the proper torque. If they are, I would start with the following steps:

Remove the cranks and bottom bracket, and check the adjustable bottom bracket cup (on the left side of the bike, when you are sitting on it). A UN-26 will have a plastic cup, which is usually a light tan color. If you've over- or under-tightened the adjustable cup, it can crack fairly quickly. This is especially true for heavier riders, or riders who tend to "mash" on the pedals up hills. This cracking will allow the bottom bracket to move in the frame, and it will wear quickly because it is not fully supported.
If the adjustable cup is not cracked or loose, move on to the fixed cup (on the right side of the bike). If it is easy to remove (being only finger tight, or taking almost no effort to remove), the bottom bracket will be able to move in the frame when you are pedaling. It will wear quickly for the same reason as #1: it is unsupported in the frame.
If neither cup is loose, or the non-drive side is not cracked, the bottom bracket shell (the part of the frame that the bottom bracket threads into) faces may not be properly aligned. The lip of the drive-side cup rests against the bottom bracket shell face.

Ideally, both faces will be parallel to each other. With traditional cup and cone bottom brackets, this was much more critical than it is with modern cartridge bearing bottom brackets. However, if the faces are far enough out of alignment, even a modern bottom bracket will wear quickly.

If you suspect that the faces are out of alignment, you may want to take the frame to your local shop to have the bottom bracket faced. This will cost between $20-$40, and will typically also include the chasing of the bottom bracket threads as well.
Finally, you may want to consider a higher quality bottom bracket. The UN-26 is entry-level quality, but if you are riding regularly and/or in inclement weather, it will wear out quickly regardless of installation quality.

Shimano makes a UN-54 bottom bracket that uses higher quality bearings and an all-metal construction.
Another good option are Tange bottom brackets, which come in a variety of sizes and use high quality bearings.
If cost is not a factor, the ne plus of bottom brackets are made by Phil Wood. Truly a "set-it-and-forget-it" product, you will have a hard time wearing out one of these. Should be professionally installed, but can last a lifetime.


Yes, frames do fail even if they're not crashed or ridden excessively harshly. The only way to mitigate this problem is to inspect the frame regularly during your maintenance and cleaning. Look for cracks. When riding, pay attention to creaks and squeeks and always find the root cause (it could be a crack).

Keep in mind that:

A bad weld could hold fine for years before coming apart.
Unchecked rust can eat through steel tubes, either from the outside-in or the inside-out. Once it starts, you have to keep on top of it or it will eventually take the frame. Rust also seems to have "good taste" in tubing by preferring the pretty Italian stuff to, say, gas-pipe schwinn.
Metal fatigue can form cracks that grow slowly until the frame suddenly snaps (I've seen this personally where the chainstay meets the dropout, and on crank arms).

Aluminum is the worst culprit for fatigue cracks. Aluminum seatposts and steerer tubes also have a tendency to develop aluminum oxide blooms that may permanently jam the seatube/steerer-tube in the frame.

Carbon typically won't survive a bad-enough crash. I've heard of long-term delamination issues, but never saw one personally. AFAIK every carbon frame "dies" in a crash or mishap that damages the frame to the point where the owner no longer trusts it. Anyone have stories about what happens to carbon that is not crashed?

For a concrete example, below is my own failure from a few years ago. It happened as I was cresting a very steep hill. I heard a loud "pop" and didn't realize what happened until I looked around and saw the chainstay separate from the dropout with each pedal stroke. This is a steel bike and was totally repairable, BTW. I didn't crash as a result (but neither was I going fast). Note the little bit of rust visible at the top of the crack. It indicates that the crack had been there for some time before the total failure.


Converting a Bicycle without gears into a Geared one?

Modifying frame is usually not worth the trouble. Maybe your bike was previously equipped with gears, and it has necessary provisions (derailleur hanger)? If not consider a hub with internal gears. If that is too expensive, consider a new bike.


Things to consider when upgrading crankset

The crank you point to would probably fit on your bottom bracket, but might result in a bad chainline.

There are two things to consider when replacing your cranks: the interface between the cranks and the bottom bracket, and the distance from the centerline.

Your old Suntour cranks and the Shimano you link to both use a JIS square taper. So the interface is fine.

However, your old cranks are designed to be installed on a 122-mm bottom-bracket spindle (and I'll assume that's what you've got), while the Shimano you link to is designed for a 113-mm spindle. You would be going from a triple to a double, which would make up for some of the difference, but I think the Shimano would wind up riding a few mm farther outboard than it's intended.

If you could find replacement chainrings that fit your cranks, that would be an easier and cheaper option, but large chainrings for mountain-bike cranks are apparently impossible to find. And I'm not sure what the BCD measurement is on your Suntour cranks.


Insurance for carless cyclist in California

I found one insurance that will be of interest for Germans:

The insurance broker OSD offers a liability insurance for German nationals that live temporarily abroad, for up to 5 years. The insurance company is called BDAE - Bund der Auslands-Erwerbstätigen, they work with Würzburger.
The liability explicitly covers bicycles "4. aus dem Besitz und dem Gebrauch von Fahrrädern;".

It has 5 million Eur coverage and is much cheaper than the renters insurance, about 100 Eur per year.

I haven't yet received a written confirmation from the U.S. based insurance that they cover bicycle liability, I'll post it when I get it. I am quite convinced that renters insurance would cover bike accidents, here is an older page with some good comments. 303 Cycling news

Update:

I went with a German international liability insurance from Allianz. It is valid for up to 5 years abroad (no time restrictions for the EU), and the clock is reset with every visit back. They confirmed this in writing.
It costs about 90 Eur per year. The max liability amount is 30 M Eur.

The U.S. renters insurance was State Farm, they confirmed on the phone that they would cover bike liability, but they never replied to me when I asked for a written confirmation.
It would have cost $270 for $2M coverage.
Many of the other insurance companies in the U.S. only offer relatively meager amounts of coverage (~ 100k), so I would recommend a closer look at State Farm for anyone interested (please post an update in that case), I am certain that they would cover bike liability, I just did not want to dig through the insurance policy when they can't be bothered to reply.


Child bike seat usage when approaching max weight

Even if you decide to buy the seat now, presumably there'd be an issue as she grows? And by the sounds of things, it won't be long before she passes the upper limit.

So I'd look at other options, which as I see it, are:

a trailer

one of those things where they're sitting on their own saddle, over their own wheel, but are actually being towed by you

or last, get her her own bike. From experience, this one has pros and cons. The obvious pro is to get them cycling as soon as possible, the con is that until they become pretty proficient, they ride mightily slowly!

While I was googling, I also came across this article which might help (and this is where the pics came from).


The little riveted points you mention are pivots, there are a bunch of them. What you can do is spray a little lubricant in each pivoting part of the derailleur, then physically move it side to side by hand a number of times and it should loosen up. Pull it towards you and then push it back, 10, 20, 30 times.
It might take a bit of force to start with and additional lubricant into the moving surfaces will flush out the dirt. Front derailleurs are quite simple mechanisms so a) you shouldn't damage it and b) if this doesn't get it moving then it is probably past it.
I've seen this numerous times with old/dirty and in particular, underused derailleurs. if someone has a triple chainset but doesn't use the smallest ring, for example, then the FD can easily seize up in time.


Can I switch through all rear gears with a two chainring crankset?

This is "older" advise that used to be gospel but these days has been engineered to be less of an issue.

The chainrings and cassettes are constructed in opposite directions.  That is the big chainring is on the outside, and the big cog in the rear cassette is on the inside nearest the midline of the bike.

Upshot, when your chain is on "big-big" meaning the biggest chainring and the biggest cog, your chain will be doing a zig-zag, with bends where it leaves the cog and where it arrives at the chainring.  Same goes for the "small-small" combo.

Realistically, this is far less of an issue than it used to be with better engineering.  Your chain may wear if you crosschain occasionally, slightly faster, but not measurably so.

Given that your bike is new, its engineering will be of modern standards and not that of 80s bike transmissions.

If you're grinding up a hill, you should be in the smaller chainring.  If you're on the flat you should be in the bigger chainring.  But a few seconds in big-big when pulling away from a red light won't upset anything.


I think this question has gone a while without an answer because it's a little unclear what you want to do... do you want to do it yourself? Or by 'experience with welding' do you mean 'experience with having welded'?

Either way, I don't have an answer for you, because I don't have direct experience welding titanium, nor do I know any welders in NJ, but I do have some tips for you:

There's nothing wrong with being a big guy and riding bikes--trust me, I know many people who do it. However, it's important to realize here that most of the higher-end bikes you've ridden haven't been designed with you in mind at all. They're designed for the cyclist who weighs twice as many pounds as he is inches tall, because that's where the market is.

And sure, titanium is technically a stronger metal than steel, but yet again, even your titanium bike is designed for the same person your steel bikes have been designed for.

Here's my suggestion: Before you spend another $100 with a welder, think about this: for the approximate price of an average new titanium frame, you could have a custom frame made from steel, but with you and your size in mind: oversized tubing, reinforced lugs, maybe even a double top-tube*. The bike would be specifically designed for you (it's been done before) and would not fail like your previous experiences.

There's lots of framebuilders in Philadelphia and New York--it can't hurt to ask around. Hope that helps!

* An aside: I actually think they look pretty cool. I'm a really tall guy, and I'm looking forward to the day when I can buy a custom-made bike that actually needs one. =]

Image Source.


Correct position of brake quick release on Ultegra 6800

It should be fully closed. The lever is only intended to be opened to allow the tire to pass during a wheel change or if you hit a pothole and knock your wheel badly out of true. If your pads are too close to the rim you make an adjustment with the barrel adjuster. Riding with the quick release open compromises the braking power of the caliper. You may not notice while riding along normally but in an emergency stop at speed it absolutely will result in slower braking.


Is this crack on my seat stay mechanically safe?

I think the key question is: how much strength is the elliptical plate brazed over the top of the seat stay adding to the strength of the joint? I'd guess it is adding some strength, as without it there is not much material between the main seat stay tube and the brazed joint. I'd be worried about a crack forming just below the joint which could lead to the stay detaching from the main triangle

However, if one stay detaches it likely won't be a catastrophic failure, because the other stay will still be supporting the rear triangle.

Really you need to consider the risk yourself. If you are a heavy rider who rides the bike hard there's more risk, obviously. At the very least I'd periodically inspect that area to check for any other cracks forming.


Convert urban/hybrid with hydraulic disk brakes from flat handlebars to drops

What you want to look for are hydraulic brakes for single-speed bikes. You can definitely get full sets including levers and calipers, I doubt you'll have luck finding levers that are compatible with the MTB calipers you have, check the manufacturers specs or get in contact with them directly to determine compatibility.

Not a recommendation, just an example, a little searching led me to TRP Hylex


Are you sure? Pedal size is pretty standard.  There is a right and a left.  If you are worried about marring up threads maybe start on the back side.  And grease the threads.


What advanced cycling skills are useful for a commuter or city rider?

Some important skills for commuters:

Looking directly behind you without turning.

This is a surprisingly difficult skill to master. When a rider looks directly backwards, it is common to turn in the direction they twisted their head. It takes a lot of practice to make resisting that turning automatic. The importance of looking behind you in traffic should be obvious.

Rapid countersteering

It is not uncommon to come up to an intersection when a vehicle in the crossing direction will come in front of you, and you will not have enough time or space to stop safely. Sometimes what is required is a countersteered* turn into the direction the crossing vehicle is traveling. This requires a quick turn of the handlebars in the opposite direction you want to turn, which will cause your center of gravity to rapidly swing to the side you want to be going. Returning the handlebars to turn in the direction you want to go completes the turn, and by doing so you can turn very rapidly with a very tight radius.

You might not be able to stop, but it can be preferable to make a sudden turn rather than crashing into something.

Stopping suddenly

Not many riders are highly skilled in using their brakes. Practice slamming on your brakes, especially using only the front, and get a feel for how much force it takes to get your back wheel off the ground. Practice to the point that when you are in a panic situation you don't simply clutch the levels with every ounce of strength, practice so modulating your brake power is a purely mechanical, automatic skill. Also practice stopping on sandy, wet, and icy surfaces.

Lesser but still important skills

Watching for people in parked cars that might open their door right in front of you while biking alongside them.
Recognizing when one of the common collision situations are upon you and how to respond defensively.
Riding on slippery surfaces.
Never stop at the stop line where 18 wheelers are turning, always stop a good distance behind so the truck has room to turn.


What child seats have a quick-release mechanism?

I know this is a late response but others like me might still refer to this page for advice. (I know I did read up on this before we made our decision)

We have just brought a Soosi Flinger bike seat for our 14 month old, 10 kg toddler. He loves sitting in it! It must be comfortable enough as he fell asleep in it during a ride! My husband likes the seat/bracket system because it is quick to take the seat off when he rides his bike to work.

Here is a link to the manufacturer's website: http://soosi.flinger.com.tw/sw-bc07-1.html


Are aerodynamic rims worth additional weight?

Obviously the prices seem to support the idea that aerodynamics matter
  more than a few hundred grams of weight, but at what point does the
  added weight offset the gain?

An exact calculation will depend on the total mass of you and your bike, your speed, the wind, its angle, whether you're climbing, on the flat, or descending, and the speed you're going (or the power you're putting out). However, we can make ballpark estimates of many of those variables to get an approximate answer.

Let's say the aero wheels add 100 grams of total mass compared to the "stock" wheels, and in return reduce your drag area, CdA, by .005 m^2. That's a ballpark improvement for a reasonably aero wheel compared to a standard box rim, though for extremely well-designed wheels you can see perhaps double that difference (~ .01 m^2) or more, especially at high yaw angles.

The power equation for a bicycle is well-understood and was given in this Bicycles Stackexchange answer. Thus to determine the point at which it is preferable to trade off lower weight for aerodynamic drag, we can substitute suitable values for mass, speed, slope, and so on, and plot the power savings, as is done here.

The figure below compares an 80 kg rider plus bike with standard box rims vs
an 80.1 kg rider plus bike with aero rims. We presume the aero rims save .005 m^2 in drag area compared to the standard rims. Three dotted lines show the power savings for a climb of 5%, a flat road, and a 5% descent. The x-axis shows the speed of the rider in km/h, while the y-axis shows the savings for the lighter wheels -- when the dotted line is above the solid horizontal zero line, it is better to have lighter wheels; when the dotted line falls below the solid horizontal zero line, it is better to have the more aerodynamic wheels.

As you can see, only for steep climbs at low speed is it preferable to have lighter wheels; however, for this particular comparison of weight savings and aero drag savings, the benefit is small, less than a watt. As speed increases, the dotted line eventually dips below zero and it becomes better to opt for the aero savings.

That was for a steep hill. On the flat and for descents, you will almost always be better off with the more aero wheels.

Note that the savings in power is still relatively modest. When racing, even small benefits can accrue to determine victory or loss, but for normal recreational riding you may want to keep the magnitude of lighter wheels vs more aero wheels in mind, especially if your budget is limited. Only you can decide whether the relative benefit is cost effective.


2009 Boxxer Team Dual Crown - Are springs different from 2010 + models?

No.  Between 2009 and 2010 the stanchion width increased by 3mm (so the spring followed), and the slider end of the 2010 spring is shaped to interface with the bottom of slider - whereas it isn't on the 2009 model.


Prescription glasses getting dusty and greasy

An ex-coworker of mine got a pair of goggles that he could put over his prescription glasses.  In his case not so much because of dirt on the lenses, but because wind bothered his eyes.

A lot of the ones you'll find are the high-durability ones for mountain bikers (with thick heavy frames), but it is possible to find lightweight (and not so ugly ones) like these:

(Note that this is not a product recommendation; I don't recall the make of what he actually has, this is simply the closest in appearance that I can find in reasonable time.)


How do I make a mountain bike go faster (commuting)

I started commuting the same way about 8 months ago on a 29'er mountain bike, 2 things made the trip faster and more enjoyable.

Firstly tyres, I changed from knobblies to slicks and it made a BIG difference both in feel and actual speed.

Secondly I got a lot stronger from biking every day.

I eventually got a lighter cheap touring bike which is faster, and better in many ways, but I still prefer the mountain bike for fun.


Leaving lock on the parking rack - is this rude?

Whether it's rude is a matter of local custom. Whether you're offended by it depends on your flexibility and sensitivity

Often, we cyclists can become a little over sensitive, after having to defend ourselves from car doors, pedestrians, cars, trucks, laws that don't take us into account, police who have a ticket quota, and even other cyclists.

Relax.

The person who left it there is just trying to save themselves the trouble of carrying it every day.

And yes, you can still park your bike there. Of course they may think you're rude then, so I'd only park there if it was the last position available.


It could be an bad valve. I had a run of flats on one bike and was sure it was something wrong in the wheel. Turns out I hadn't replaced the tubes in a long time so the tubes I installed were also old. Both failed where the stem meets the tube.  The pressure needed to be high and it took about 45mins to go flat.


Your rear derailleur is out of adjustment, possibly because it was knocked against something. There are already many good guides to derailleur adjustment on the internet, so I'd rather link to one from one from Park Tool than write another one. If your derailleur has been knocked badly out of alignment, you might also need to realign the hanger.


If you have a six-speed rear cogset the bike is either inexpensive or seriously old; such things have long since been replaced by 7-8-9 or 10-speed gearsets.

At any rate, the important thing with a rear DR is "capacity".  It must have sufficient arm length to handle the range of gears on the cassette or freewheel.
Most all DRs have sufficient side-to-side movement, so the factor you're looking for is the length of the "arm" with the two rollers on it.
Longer arm, more capacity.
If you look at high-end road bikes with very "close" gearsets, you'll see the arm is very short.   Look at mountain bikes which have great big low gears, and you'll see longer ones.

Also... Cheaper DRs such as found on many "box-store" import bikes often mount on a steel piece that is bolted into the dropout. (where the axle goes)
Better DRs mount on a "hanger" which is often replaceable; these may have a different mounting screw.
Just take the old one with you to the bike shop and they should be able to find a good replacement.


I have not used a bottle dynamo for a very long time, but have a hub dynamo. Broadly, the hub dynamos are more expensive but more efficient - you get less drag for the same power output. Most systems put out 3W peak power for historical reasons, although a lot of new lights use less than this. Bottle dynamos are noisier and wear on your tyre, which may be an issue if your tyres otherwise last a long time. A good bottle dyno will be nearly as efficient as a hub dyno and cost about half as much, plus you don't have to build it into the wheel. A cheap bottle dyno should be removed and thrown away.

Some dynamos will put out more than 6V, which is how you can get more power out of them (the Schmidt ones do - I used to run a 5W white LED straight off one). Often at decent speed they will go to 12V at the same 500mA, so you can get 6W. There are also dynamos specifically designed to do this, and they usually come with a regulator and various output options for charging things like phones.

Hub dynamo systems cost at least a couple of hundred dollars because you need to build the dynamo into a wheel. But they last a long time (I don't know how long as I've only had mine for 10 years and the ones I know of that have failed have done so when the bike was destroyed around them, or the owner pulled them apart). Any decent LBS should be able to get them if they don't stock them, or refer you to one who does. Peter White Cycles is one of the better dealers in the US with a wide range of options, likewise St Kilda Cycles in Australia.

I think this is a reasonable overview and this gives more details, specifically discussion of the "more power" idea.


Converting a short cage rear derailleur to a long cage derailleur

Yes, if the derailleurs are the same model, and you can get all the parts, (which isn't usually a straightforward process) youcan convert from short cage to long cage.


What is the “clip ring” part on my hubs?

Is there a small hole that was covered by the ring? If so it covers a lubrication port. Many old Raleigh, and other utility type hubs came with such a port.


2.8Nm for a collar on a steel/aluminum post is incredibly small. My carbon frame bike (with aluminum seatpost) specifies 5nm and 5-7 is a common value (Refer park tool website).  I probably run around 2Nm, as I use carbon paste and have it no tighter than needed to stay put, but would happily go higher if needed.

First have you cleaned and greased the threads of the clamp bolt. This makes a big difference to the clamping force at a given torque.  If you want to stay at 2.8nm, try carbon paste. Its designed to increase friction and reduce required clamping forces on carbon, but works well on metals.

Without suggesting you become "A gorilla with a spanner"  - You could "over torque" the clamp (or replace the clamp that has a larger number printed on it). I can't imagine crushing a steel frame/aluminum post at any reasonable torque you can get onto the bolt size a seat post clamp has. I would have a guess many seat posts on steel bikes are clamped at 10 times or more that value with the only problem being getting them undone when needed.


What make/brand is this bike marked "Challenger" and "Resistance"?

The usual method of identifying a bike is what you've done.

The brand and model are usually part of the decals on the frame.

My bike, for example, says Scott on the downtube, and CR1 Pro on the toptube near the headset.

It is Swiss made, and the model stands for comfort road 1, and Pro tells you what parts were on it originally.

If there are no decals, an experienced mechanic or shop owner can usually identify most common frames.

Your bike is very basic, at best, and most people would not consider it safe for use on off road trails. I would recommend looking for a shop quality mountain bike. You will enjoy riding more, and that is what it's all about.  Feel free to ask if you need more information.


Are there pedals that are both flat and cleated on each side?

I think the most approximate thing, at least on Shimano is the Shimano PD-M424, which is a clipless pedal with a resin cage, or the Shimano PD-M545 which is the same but with an alluminum cage.

I have been using these on MTB and commuting since year 2000 and I think they would fit your needs. The are easy to Clip In an out, but the cage provides very good support when used with regular shoes. I have commuted with those kind of pedals using Tennis shoes, flip-flops and even Office Shoes (with rubber soles). I have used hiking shoes to MTB with them and with good performance.

There are other similar like the Shimano PD-M647.

My father used them too with regular running shoes in light XC riding for years until I convinced him that platforms would be cheaper and more comfortable (He would never use clips).

The only care you must take for serious riding is that the shoe must have good sole texture, so it kind of grabs the center of the pedal and has good grip to the cage, because they are less safe than plain platform pedals.

Another Solution for you are these platforms that attach to the clipless mechanism, converting your regular clipless pedals into platforms. http://problemsolversbike.com/products/deckster_clipless_pedal_adapter. You need to buy extra cleats because the platform adapter dos not include it. This kind of solution would be a little cumbersome as you would have to install the platforms for commuting days and remove them for performance riding.

I'm pretty sure that a skilled machinist with the right tools can craft a DIY version of these, that has a cleat-like shape incorporated so it has a flatter profile. (I have this project in my bucket list)

Finally a tip: your complaint about too much clipping/unclipping makes me think that it is (still) kind of difficult for you to do so, but it shouldn't. As you get more practice, clipping in and out becomes so natural that you won't be counting how many times you do it. Second, adjusting the mechanism tension to a lower setting makes it easier to pull out of it. Personally, I use mine in the lowest possible setting but I don't have unexpected  release issues, and I constantly lift the bike by pulling both pedals up.


According to info from Sheldon Brown, Your Giant post is most likely to be 30.8 as this seems to be a common size on with that brand - however you don't give the age and model of the bike, so it could be Giant changed to another size. The conspiracy theorist in me thinks its so they sell a whole new bike when to can't find a matching seat post.

I have also had this problem (With another brand), and beyond trawling ebay and craigs list in the vain hope sellers will put the size on the listing and its accurate, your best bet is to try your luck with your corner LBS (Not the chain-shop who only has this years stock and is shiny and flash) - good chance they have one in back somewhere. Shops that have been around for a while tend to keep boxes of odd ball sized parts such as these, (rather than throw them away) as it's good for business being the "The only guy in town who...." kind of place.


I am roughly your size (same inseam 5'8") and 52cm for a "standard" diamond frame bike would be too small for me. With a long enough stem I could get the bars in roughly the right place, but it they would likely be too low without some serious bogdery with stem riser extensions. But if you're young and flexible enough to deal with the low bar position it might work for you.
However, 52cm doesn't really tell us enough about the exact frame geometry to know whether this bike is appropriate or not. It's close enough that you can likely ride it safely if not as comfortably as possible. A picture or link to the exact bike would help a lot in answering this question.
A bike only becomes "unsafe" when you can't get the proper seat height w/o having enough seat post in the frame seat tube. There are markings on the seat post ( generally around 4 inches). Or you can't pedal the bike w/o your knees hitting the handlebars ( generally this is when standing to pedal).
Beyond the basics bike sizing is mostly about getting the compromise of comfort and efficiency in fit that works for you. If you were a pro bike racer, 52cm might be ideal. For the average rider, you can likely make the bike "work", but you'd be more comfortable on a slightly bigger bike ( either 54 or 56cm depending on exact geometry.)


Vibram is simply a brand name for rubber soles made by Vibram S.p.A. of Italy. The actual composition of the rubber and the lug design used differs across their product line, with specialized compounds for hiking, industrial use, and for their "Five Fingers" barefoot running shoes.

They began as a manufacturer for hiking shoes and were one of the first to make them with rubber soles, which helped them become a well-known brand in that market.

The manufacturers of MTB tires are continually experimenting with new rubber compounds and balancing durability, weight, and traction. I'd expect that Vibram S.p.A. doesn't see much opportunity in becoming a bicycle tire manufacturer.


Check for something that has easily available parts.  If you buy a bike that's too old, then new parts won't fit on it properly, and you'll have to either find old parts in good condition, or pay more for parts because they aren't made in high volume anymore.  I guess if you're talking about a commuter, then it's going to be a road bike. Make sure that it has 700c wheels, or can accomodate them.  Otherwise, finding 27 inch wheels and tires can be a bit of a pain.


Need help picking the right rear derailleur and chain for Giant Escape 2

All 8- and 9-speed Shimano mountain derailleurs are compatible. Just pick one that you like. The one thing to worry is long cage versus extra long cage, and unless you know you have an extra wide range of gears, long cage is fine.

The chain is also fine. If you are changing the chain because is worn out or "stretched", you should probably replace the rear cogs too.


Why do so many people put the inside pedal down when cornering?

People put the inside pedal down because it's the natural thing to do. You want the bike to lean to the left, so you press down on the left side; you want the bike to lean right, so you press on the right.

Putting the outside pedal down is a learnt behaviour, so it's only done by people who have been taught it. Also, most people don't cycle fast and aren't on road bikes, so they're not leaning the bike much and they have reasonably high bottom brackets. Pedal strikes simply aren't an issue for most cyclists.


restoring old bike, remove scratched stickers, yes or no?

If you feel the bike has no significant resale value, then why not just do what would produce the results YOU would like the most?

But if you really want to preserve the stickers, but want to avoid the trouble and less than ideal paint job due to masking them, I'm guessing it would be possible to photograph (and PhotoShop) them (or find matching images on the web) and then reproduce them somehow with a reasonably waterproof printing scheme.


How to collect Shimano ALTUS parts together?

Shifters are notoriously hard to reassemble, and if it came to pieces unexpectedly it's going to be hard to know whether you've got everything. You also don't know (until you've put all the effort in to try and fix it) whether the reason it gave you trouble in the first place is something you can fix. An Altus shifter shouldn't be expensive so it's probably best to replace it.


What shifters are compatible with the 8 speed cassette and Deore derailleur on my Trek 6500 ZX?

Any 8-speed Shimano mountain bike shifter will work. All Shimano 8-speed shifters use the same cable pull.

Addressing what model your actual shifters are, a `97 8 speed MTB with a 'Deore' drivetrain probably has Deore XT M739 and Deore LX M569 parts. (See the Shimano Wikipedia page which includes a timeline of MTB groupsets.)

You could narrow down the exact model you have, then try to find a lightly used or old stock replacement on EBay. Googling for 'M739 Shifter' for instance yields images that you can compare to what's on your bike.

Many shifters from about this time were combined shifters and brake levers. If you have cantilever brakes be aware that the brake levers for cantis and linear pull (v-brakes) are different. Newer shift-brake combos will be for linear pull brakes and will not work with cantilevers.

I don't think Shimano currently makes an 8-speed groupset above Tourney level. But you could also look at newer 8-speed shifters from the Alivio/Acera goupsets.


So eventually it seems I figured it out!

The chain was indeed vibrating like a guitar string at speed. This was caused by a couple of rear gears ever so slightly out of alignment. They shifted ok but I could see the chain was marginally catching on some rear cogs.

A small adjustment of the gears with the dial on the gear shift and a good grease of the chain and it was running silent :)


Why is buying a bike as a whole cheaper than buying separate parts and building it?

Economics of scale.

For instance, when a bike manufacturer buys thousands of groupsets directly from a component manufacturer, they get a significantly better per unit price than a retailer can.

The retailer not only must necessarily buy in lower volume, but also typically buys through one or more layers of middlemen, each layer adding their cut to the wholesale price.

Thus, the typical replacement price for a single part is often double or more than the original cost to install it at the manufacturer of the bike.


To keep your chain from breaking, keep the derailers properly aligned, ease off of pedaling when you shift, and don't "stomp" on the chain when it's not fully in gear.  (Folks who don't go back to the non-indexed days probably never got into the habit of coasting while shifting, but it wouldn't be a bad thing to practice a bit.)

Broken chains are exceedingly rare, and are almost always the result of putting load on the chain when it's not fully in gear.  The other likely source of damage is having sprockets that are so badly hooked that the chain gets sucked into a knot.

Update -- 6/14/18

An observation I made this week, working on a bike for Christmas Anonymous:

The bike (a 26" full susp BSO) came in with a mangled chain, a mangled rear wheel (half the spokes were broken), and a broken rear derailer.  The chain had actually been twisted 90 degrees at one point (amazing that it didn't break), something I'd never seen before.  It seemed like the chain had gotten twisted up in the rear cluster perhaps, after the rear wheel had gotten mucked up.  (Perhaps a garage accident -- hard to tell with such things.)

So I found a new rear wheel, a new rear derailer, and a new chain, and put it all together.  The rear derailer worked fine, once I got it adjusted (involved some cussing), but then as I tried to get the front derailer to work (blasted twist shifters, plus a cable that was routed so that it collected rainwater) I started having trouble with chain suck on the small front ring.  I could see that this chain suck likely caused the chain to knot up and twist, and it was only after that that the garage accident occurred, taking out both wheel and derailer.

Since the chain suck was consistently on two teeth a one point on the small ring, I was able to use a round file to smooth out the teeth and eliminate the problem.  I'm guessing the teeth had burrs from when the ring was manufactured, and the bike never got used enough to wear them off.


This era of bicycle is especially hard to pin, it could be a Elgin, Hawthorne/Wards, Phillips, an Iver Johnson or many others that were making similar bikes. Do the pedals have any words on them embossed in the plastic?

If i had to guess i would agree that it is a Pre-WWII as other have said probably around mid to late 30's. Many frames back then had the dual top tubes however many had a bend in the upper one and a "gas tank" in between them. I assume there is not head badge or any other kind of markings? If original the hub and components may lend some information but it is difficult to say from this era.

The saddle was likely a dual rear spring leather "brooks" style saddle that looked something like the one seen on this Iver Johnson:


Missing mtb bottom bracket cable guide screw?

If you are concerned about the empty hole next to the Phillips head screw, you can ease your concern. The cable guide typically only needs a single mounting screw. The extra hole allows the same cable guide to fit a variety of bikes by  shifting the guide towards the drive or non drive side depending on which hole is used.


Are you able to remove the wheel? Once the wheel is removed amd the pads are no longer obstructed by the brake rotor, you need to insert a flat-bladed screwdriver between the pads and twist it to push the pads apart. If this works, then you should be able to put the wheel back in, fitting the rotor into the brake caliper. With everything back in place, try pulling the brake lever again to see if it works properly now.

If this doesn't work, then you probably have a more complicated issue that we would need more information to diagnose.


There are 2 marks that I see:

The black mark - as someone noted in the comments - looks like it is due to the brake cable rubbing on the frame. Fairly typical.
The "cracks" on the white paint are a type of paint failure I have seen before, though it might not have been on a bike frame. It probably is nothing to worry about.

When/if you meet them, ask them whether the bike was in a crash. It probably wasn't. Take comfort in the fact that they posted this picture; only an honest seller would note such imperfections in an ad.


Replacement for a Suntour Superbe front derailleur

Suntour Superbe parts were great, but they have been out of production for decades, and in any case, technology has marched on. Finding a direct replacement part might appeal to vintage enthusiasts, but there's no need to do so for functional reasons. New front derailleurs may have a slightly shorter maximum "throw" because chainrings are spaced closer these days. I don't know whether this would affect you, but I'm guessing not.

One quirk of the Klein is tubing diameters that were at the time considered oversize. As best as I can determine, Klein seat tubes had a "normal" diameter of 1¼", which is a good fit for the clamps on modern front derailleurs, but I would double-check that just to make sure.


Changing the middle chainring on a 3-chainring crank

You'll have to 'mess' minimally with the FD in a way that you'll have to adjust the min/max screws to lock the FD in position and (better) remove the cable. Leave the derailleur in place as it will act as a chain-guide.


Fortified Bicycle appears to gone out of business -- where to get one of their replacement bike light batteries?

If your light is not sealed, and you can see a battery that looks like this

(the colour/color does not matter) then you can pop out all the old batteries and fit new ones.   Replace all the batteries in one light together, don't mix and match.  The old ones should be recycled properly.
If the current batteries are soldered in, then its still possible to swap them, just takes more effort.
Aside, "18350" is a dimension, being 18mm across, 35mm long, and 0 means a round/cylindrical casing.   18mm diameter is slightly thicker than a common AA battery which is a 16mm diameter.
Matching the voltage and chemistry is important - you can't put a 1.5V battery in place of a 3.7V battery, because it probably won't work and it definitely won't charge safely.  Matching the size helps stop things from rattling about and becoming loose.

Additionally there is another size of battery called a 16340, which is 2mm smaller in diameter.  This is also known as a CR123A, which might be an acceptable fit if you add some tape around the outside as packing.  Note this battery can come as a disposable or as a rechargeable lithium-based chemistry.  Don't recharge a disposable.


Nice Work Shoes That Won't Get Messed up in Toe-Clips

Don't change the shoes, change the pedal. A hybrid pedal would satisfy both needs. It features a clip and a flat "normal shoes" side. Because for commuting sport-like conditions are probably not so important.

http://bike.shimano.com/publish/content/global_cycle/en/us/index/products/pedals/mountain/product.-code-PD-A530.-type-.pd_mountain.html

greets Josef


Can I grease a crank spindle/bracket without disassembling the crank set?

I'm going to offer the contrary answer - why not fix it properly?

Summary:  Your spindle/crank interface is damaged, so the crank has been forced onto the spindle and is now at a high state of torque.  Its confirmed that the spindle is damaged and likely that the crank arm is now damaged as a result.  And the rest of the bike is OK.

So the worst case is that your BB needs replacing, and that the crank arm is damaged enough to need replacing too.

Replacing the BB with a nice new cartridge will give you a new spindle/axle, and it will give you a much better pedal feel.   You will have to match the new spindle to your crank's interface, being square taper or octalink or whatever.

You won't know if the crank's a writeoff till you get it off.  So pick a time when you don't need the bike for a bit and can work on it.

Consider that had you changed the BB for a new cartridge, the crank arm would have gone on easier and not been damaged.  By cramming it back together, you've made your problem worse.  Do it right sooner, not postpone till later.

Just cos the bike had an initial cost to you of 2x coffees, doesn't mean its junk.  You could look for another donor bike to salvage some cranks, or check Ebay/craigslist/gumtree/etc.

Note that your left and right crank don't need to match, they just need the same fittings and same overall length.

As for getting the current one off - leverage will help.  If the bolt shears then the stub will be in the BB spindle/axle which is trash anyway, and the new one will come with replacement bolts.

You don't need a LBS for this - its dirty but its not hard.  The only tool that will be odd is the fitting for the ends of the cartridge.


Vintage Peugeot pulls towards left when riding

Straighten your seat. It's pointed a bit to the right, causing your body to slightly slant to the left to compensate, moving center of the mass a bit to the left, causing whole bike to lean and turn left.


Kalkhoff Agattu (e-bike) Panasonic 24v engine dead - worth repairing?

First up - I know nothing about your specific bike model.  However 3 years is a pretty good run for batteries especially if used for hill climbing, and it could be they're just past it and need replacing.

600 euros sounds a lot, but its one of the consumables.  Do you know how far you're ridden?  10,000 km would be 0.06 euros per km, which is a lot cheaper than a car.

Its highly unlikely the battery shorted the motor and the motor shorted the battery killing both.

If you're handy, try and find two working 12V batteries (car ones would do) and hook them up in series to the leads, with your powered wheel off the ground.  Do mind the polarity and watch for shorting.  The bike should run like normal on 24V.  For this test, battery type doesn't matter but current will need to be at least 10 amps so small batteries are unsuitable. If this works, the motor is fine.  You might be able to use a mains PSU adapter, provided it supplies 24V DC at 10-15 Amps.

If this doesn't work, the motor or controller may be damaged and you need some more skilled local help.  Google about for an ebike retailer or specialist in your region.

Best to google about for a replacement battery pack or find a battery specialist who can repack your existing battery.

A bike is not a cellphone to be replaced every couple of years, with normal maintenance it should last for decades.


Frankly, unless you are willing to swap to a disc brake bike, you are out of luck. I assume that you are riding the bike regularly, but I would not expect to get more than 1-2 months out of a rubber or cork road brake pad (Cork is typically only used on carbon fiber rims). Especially in a hilly area. You can extend the life slightly by ensuring your rims are clean and dry, but only by a small percentage. A bike ridden in wet weather can use up a set of rubber brake pads in one ride. 1/2 a season or more is an excellent usable life for this type of pad.

A disc brake pad will last much longer, because the pads are made of sintered metal, like the pads in your car. Average life is 1 to 2 years, with variation in riding style and weather. That requires changing at minimum your wheels and brakes, but most likely would require a new bike. Not something I would consider cost effective solely to save money on brake pads.


Do pros ride with 1X configuration on some courses?

Yes, they sometimes do (or at least announce/intend to), here are two examples:

  This is the 3T Strada that Aqua Blue Sport will ride in 2018, making
  the Irish-based squad the first pro cycling team to use a
  single-chainring drivetrain.

Source

  One ring to rule them all: Tony Martin's Canyon Speedmax 58x11-32 on
  the world champ's time trial rig

Source


Will 40km E-Bike trip in Texel Island(Holland) be hard for untrained people?

Short answer: No you'll be fine and (if the weather allows) you'll have a wonderful day.

Longer answer: You are on an e-bike, 40km is about two hours of riding on an e-bike. This is independent of fitness, because you are on an e-bike. Saddlesoreness (is that a word?) might be an issue, but given that you have 8 hours total you can bike short bits with long breaks in between to rest your tender bits. If it turns out range is an issue you'll come across dozens of places where you can use those same six hours you have left to charge your batteries. Texel isn't crowded by dutch standards but it is by no means empty.

The highest point of Texel is 15.3m above sea level, the lowest point about 1m below, so hills are not an issue either.

More than your fitness level I expect the weather (rain and/or wind) might be an issue.


The guy using it apparently is Hans-Henrik Oersted who was sponsered by chinelli. The company recently did a rerun of two jerseys to honor him.
The picture can also be found on cinellis website about the jerseys so i wrote a request for information to their customer service.
They answered it is a handmade trainer build especially for Hans-Henrik Oersted in the 80's. It was never for sale.


What GPS unit should I get? Or, is there a better app I could use to log my rides?

I've been quite happy using Cyclemeter (the iPhone version). I use it with a Wahoo RFLKT+ to get a display and ANT+ bridge. There are also some good looking mounts available, I really like the looks of the Rokform mounts but I haven't used them.


There are 3 basic hand positions that most people use on a drop bar:

On the Hoods - This position allows you to reach the brakes and shifters without moving your hands and allows a fairly upright, and comfortable body position. Most riders spend 75-90% of their miles in this position.

On the Drops - This position is ideal for more aerodynamic body positions, or more athletic efforts. When you want to go hard, go here. You can reach brakes and shifters, but may have to move your hands, depending on your setup. This is generally used for descending long hills, or an aggressive position. It is less stable, and it is used for maybe 10% or less of most riders' mileage.

On the Tops - This position allows a comfortable alternative position for more relaxed riding. It is generally used when going at an easy pace, and in situations where you are certain of the road conditions, traffic and other hazards. You definitely can not reach the brakes or shifters from this position without moving your hands. It is less stable due to narrower hand position, though it may not feel like it. Most riders use it as a cool down position for 10% or so of their mileage.


What gauge wire is used for dynamo hubs and lights?

Won't matter much, 22AWG is rated at about 1AMP for power transmission and 7AMP maximum current (i.e. that is around the current insulation starts to melt), is plenty large enough to carry the current from a dynamo (a few hundred milliamp's) and provides a strong enough wire that it won't break easily when in use.  A size or two smaller or larger won't hurt.


What bicycle to buy for commuting to work and for leisure (Aberdeen)

1) As in Scotland, I would recommend you to look for a second-hand bike (possibly gumtree is a good place to start with, bear in mind that you need to check and make sure the bike is not stolen). The reason is that in the winter, all the salt on the roads will corrode your bike badly.So go cheap, then keep it as winter bike, then upgrade gradually.

Cyclocross would be your choice if you are planning to cycling offroad and over glens.

If you are just going to stick along the coast, a road bike would be enough (and pretty fast too, so you can go to Stonehaven, Montrose, even up to Inverness).

2) A road bike as for starter (second hand) is around £100-150 (Carrera Virtuoso for example, I got one for £110, model 2012)

A cyclocross for starter (second hand) is around £150-200. The higher price reflects that not many people in Scotland buy/own cyclocross (I have yet to see one cyclocross bike in Dundee). A little search around Aberdeen shows Carrera Crixus selling at around £200.

3) 700c wheel of course :-) 26" will be like a toddler-bike for you

Your height is not telling much, but if you are an average guy, 1.82 m would need a 22" (L or 54-56cm), between 21" and 22" also ok-ish. Having said, I'm 1.73 but I need a slightly larger one comparing to my height (20.5" or 52-54 cm), because my back is quiet short, relatively to my legs.


Sharing an 11 speed SRAM wheel with an 11 speed Campagnolo

In theory, you would want to make sure that the cog-cog distance for each cassette is preferably equal, or at least close enough. You may need to adjust your limit screws as well when changing wheels. Campagnolo maintains variable spacing between its cogs, whereas neither SRAM nor Shimano do. Ergo, while the average cog-cog distance is identical, the actual distance between cogs is slightly different on Campagnolo cassettes.
However, these differences are not of practical significance. 11s cassettes are functionally interchangeable across all 3 manufacturers. This is widely known.
Some riders report that they prefer to keep a like chain or a 'neutral' chain (as opposed to a competitor's chain) with a like cassette to maximize shifting performance. For example, with a Campagnolo cassette on a Shimano drivetrain, riders might prefer a Campagnolo chain, or if not then a KMC or Yaban chain. However, I'm not certain how much of this is a placebo effect versus an actual shifting difference.
12s cassettes from the big 3 groups should be interchangeable as well, at least in terms of cog-cog distance. There simply isn't enough space left for them to vary in that dimension. If you are planning to interchange cassette types on a 12s system, note that SRAM's AXS 12s chain may only be officially compatible with SRAM cogs and chainrings, because that chain has slightly larger rollers specified. I believe I have heard some riders remark that this is, again, not a practical concern, but I haven't kept track of this issue.