Why did I lose braking power after hitting a curb?

Based on the second photo, I'd guess the rotor is no longer parallel to the brake caliper.
Thus instead of having flat contact between the pads and the rotor like
=| |x| |=

you now have smaller area of contact.
=/ |x| /=

Sanding the pads has rounded them off a little, increasing the area of contact a little.

The best fix I can come up with is re-aligning the caliper with the rotor.

Take out the front wheel and fit a slip of paper over the rotor, then reinstall so the paper is in the caliper.
Back off both bolts holding the caliper to the fork, enough so it can slide.
Press and hold the brake lever on the handlebars and help the caliper find its center.
Tighten the two bolts sufficiently (not excessively)
Release the brake lever
Spin the wheel to pop the paper out, and test.  You're looking for no-rubbing and that the pads touch the rotor all-at-once.

Small changes will have a big effect on the brakes.
The problem may be if the little mounts that support the caliper have been bent, or if the caliper's mounting tabs have bent, or if the mounting bolts are bent.
You might need to replace both bolts if they are not straight.
I would not recommend attempting to straighten the caliper if its bent - they will probably break, or if not will be weakened.
If the fork's mount points are bent, you may be able to file/mill/sand the top surfaces to be flat and at right angles again, but it is hard to get perfect.
Upshot - avoid riding your bike into kerbs/curbs.


What is the best way to stop and restart at a stoplight?

These are the options I use depending on the circumstances:

Trackstand: Requires a lot of practice and it is a bit of a swhowoff. (This is the one I use the less)
Partially Dismount: Preferred when riding cleated pedals. Dominant foot stays on the pedal, and the pedal is kept ready for a full stroke (at 45 degrees over the horizontal as the other answer says). The other foot goes to the pavement. Preferred on busy crossings or when I have to use a lane not next to the curb.
Right foot on the curb: My Right foot is the dominant one, but when I get to stop besides a curb, the fact that I remain in the saddle almost makes up for having to take the first stroke with the left.
Use your hands: When there is a light pole or a suitable road sign, I keep mounted (and cleated) and use my hand to keep balance. Sometimes I can even put the shoulder against a pole or wall or the end of the handlebar. This one lets me re start fully engaged to pedals.


is it possible to put a bigger than 34t chainring on Merida e160?

Depends what you mean by clearance. X or Y in the diagram below?

if you mean X then you likely have room for a bigger chainring. If you mean Y then you are probably out of luck.

Using a formula for the radius of an n sided polygon and assuming tooth profile does not significantly vary for different size chainrings, each additional tooth adds about 2mm of radius to the chainring.


Summer Reading Recommendation: Bike Touring (Canada)

Over the Hills, by David Lamb

Not related to Canada, but this book a great first-tourer story; it also encouraged my own interest in touring -- along with John Doesey's wonderful tour journal, the first one I ever read.

Over the Hills is a memoir of a middle-aged journalist’s 3000-mile "afternoon ride". The book is well-written, fun to read, and strikes an excellent balance between travelogue, personal memoir, and barely disguised worship of middle America’s relaxed way of life.

The author is decidedly not part of bicycling culture. He wore ordinary-looking clothing on his trip, ate in ordinary diners and truck stops, and stayed in ordinary hotel rooms, with his bike standing by the side of the bed. Mr. Lamb is very much a character in his own story.

Funny story, from the middle of a Boston to New York City tour: I was pushing my way up a hill on the way to a repair shop, and chatted with a guy on a motorcycle; he started to describe this book, and I interrupted him, asking if it was this book. We both laughed; it was a bonding moment.

I learned a few things from this book: To keep my hands loose on the bars when going over grooved pavement, that it's not "cheating" to accept a ride to get past an onerous section of interstate, and that talking to strangers is just plain fun.


I am 6ft and riding a firefox kompac. My speed never crosses 18kmph

What is your "cadence" (number of pedal revolutions per minute)?  A healthy young cyclist should be able to "cruise" at 80-90 rpm, and that would be considered your top speed.

If at 80 rpm you're only getting 18kmph (11mph) in your fastest gear then your bike gearing is quite low and you probably need to change something.  But many novice cyclists simply pedal too slowly.

With a multi-speed bike you should focus first on getting a "reasonable" cadence (maybe 60 rpm when "taking it easy", 80-90 when trying to go fast).  "Gear down" into an easier gear until you learn to maintain cadence, then slowly increase gear difficulty to gain strength and stamina.


With the exception of a very few wheels that have a low maximum rider weight, the only real reasons not to use your TT wheels all the time are:

Cost - do you want the daily road grime all over your $2,500 carbon wheels?
Surface area - cross winds when your rolling >80mm dishes can become interesting
Braking surface - related to (1)...you will eventually wear down the braking surface.
Flats - these days a lot of TT wheels are clinchers, but if yours are tubular, carrying a spare tire all the time may not be ideal. For more than a race, you'll need to really protect the glue.

I might add a (5) that some people will think you are a poser with more money than talent...but I personally think rolling around in some deep carbon is cool.

The few wheels that have the low max weight could fall apart as they get beaten on the bumps and dips of daily riding, the vast majority are probably just about as strong as (or possibly stronger than) the wheels you are rolling right now.

Happy Riding.


Drop stem on endurance bike to get the geometry closer to road performance?

Yes, you can get a more aggressive riding position by dropping the stem down on the steerer tube, and swapping the stem for one with a larger angle (and possibly a different length).

Bikes typically come with 3 5mm spacers, and swapping from a 6 to 12 degree 100mm stem drops an additional 10mm, so you should be able to easily drop the bars by 35mm.

What we cannot tell you is whether you will be able to get the bars low enough for you. I suggest that you use you current bike as a baseline if it is set up the way you like it. Measure its stack and stem rise, then compare that to the bike you are looking at. Also, go get a test ride if that is possible in your location, or at least sit on the bike and get a feel for the rider position.

There are other differences in steering geometry between the bike you are looking at and the higher end ones. The higher end ones have slightly steeper head tube angles and will have slightly quicker steering. Again, you will have to determine if that works for you.


Stretching has become somewhat controversial among exercise physiologists.   I listened to one such lady on NPR's Science Friday a couple of months ago, and she said that the university she worked out of had conducted a number of fairly extensive tests and surveys indicating that very little benefit accrued from this practice.
Other than that it felt kind of good. Wired's Pre-Exercise Stretching Is Killing Your Workout article discusses such studies.

I've never bothered with pre-ride stretching.  In fact, the standard wisdom is that one should first warm up and THEN stretch.
Ride slowly, let the legs get used to spinning and the arms used to bearing a bit of weight before increasing your pace.
I used to stretch post-ride; the standard quad and hamstrings stretches and also calf-muscle stretches by standing with my toes on a stair and letting body-weight stretch the calf... But I admit I hardly bother anymore.


How does front projection affect stability?

Jones refers to the horizontal distance between the front wheel axle and the steering axis as front projection. Front projection is the product of the fork offset (the displacement between the axle and steering axis, measured at angle perpendicular to the steering axis, not the ground) and the sine of the head angle (the angle between the ground and the steering axis). Fork offset is a measurement of the fork itself, front projection refers to the assembly of fork + frame.
The theory on negative front projection, as I understand it, is similar to the theory on trail.
Trail is the distance parallel to the ground between the steering axis and the center of the tire’s contact patch. With the fork pointed straight ahead, the contact area on most bikes will be behind the steering axis. This is because most bikes have a head angle between 0 and 90 degrees, and on most bikes, tan(head angle)*fork offset is less than the radius of the wheel. That is to say that for the same head angle, a larger front wheel and/or a smaller fork offset, will result in more trail. This pattern continues with negative fork offsets (I.e. the front axle being behind the steering axle, or mounting the fork backwards) as well.
Another measure that’s applied to steering geometries is mechanical trail. Mechanical trail is like ordinary trail except instead of measuring parallel to the ground, mechanical trail is the displacement perpendicular to the steering axis.
My understanding is that there are many theories on why a bicycle should be stable, but for me the easiest to visualize in terms of actively balancing, involves an inverted pendulum. If you’re tipping over to the left, you fix it by first pointing the handlebars towards the left, to bring the wheels under you. Likewise, if you were balancing a broomstick on your hand, and it was tipping to the left, you move your hand left to bring the fulcrum in line with its center of gravity.
The bike with negative front projection doesn’t get stable from turning into a lean simply because low center of gravity=stable; it gets stability because it has a greater tendency to turn in the direction of the lean, and turning in the direction of a lean is how you keep a bicycle upright. The backwards fork increases the tendency to turn towards a lean because the lever arm operating on the steering assembly (the mechanical trail) is greater.
Why does mechanical trail make a bike more stable? My understanding is that the friction force between the ground and the tire corrects the steering direction, and the more that force is offset from the steering axis, the more influence it has. When the bike is standing upright and rolling forward, mechanical trail tends to re-center the steering. Conversely, if you hold the bike upright and try to rotate the frame about the rear tire, because the front tire’s contact patch is behind the steering axis, it will rotate the steering assembly in the same direction. If you push the front of the frame to the left, you get a rightward force from the ground acting on the tire, and because it’s behind the steering axis, it creates a torque on the steering assembly turning the handlebars to the left. that translates into turning the front wheel into a lean when the bike is leaning, and helping it stay straight when the bike is upright.


How should I handle a highway patrolman who stops me occasionally to give incorrect instructions about my riding duties?

There is no one size fits all answer to this, except the first point below.

When dealing with police, or other authority figures, always behave respectfully.
Contact the people responsible for sweeping the road and ask when or if they are going to do it next. Maybe they only sweep when requested.
Find out if there's a local bike advocacy group. They would have a history of such contact and possibly have established communication channels. If they exist then talk to them.
Failing that, then get dressed in a suit or other best clothes, and drop in to the police station with your bike to talk with the duty officer, probably a Sgt. Explain what the problem is and how you've dealt with it. Also explain that you're not complaining, just would like to not get stopped regularly. Also ask if there's a specialist cycling officer to talk to. And make sure you ask why it's happening, to get the story from their side. Do not create a you-versus-them situation, because they have the power and you lose. Once the discussion is started you can show what a sensible and reasonable citizen you are and get them on your side. It's possible that a motorist or some senior member of the community has complained (not necessarily about you), or that they have received a directive from higher up. I guess the point here is don't go in expecting them to suddenly roll over. Look for common ground and understanding.
Invite the police to come for a ride with you. Of course you would take them along that stretch of road.

Good luck.


When I pedal they keep shifting forward randomly but not moving the bike forward

It most likely is a freewheel failure. If your bike has 7 or less cogs in the rear it almost surely is a freewheel. If it has 8 it may be freewheel or freehub. 9 or more cogs almost always a freehub.

The failure shown in the video may be caused by 2 things:

The pawls are unable to engage because they are seized due to
corrosion or the lube/grease has dried up.
The pawls are broken or the springs that make them engage are
broken.

Photo of a freewheel showing the ratcheting mechanism components

In the first case dropping penetrating oil into the ratcheting mechanism may free the pawls, but it is not guaranteed. The correct solution is to open the ratchet, clean it thoroughly and re build it using fresh lube.

Opening a freewheel is a delicate thing, requieres either special tools or the ability to "hack" common tools without damaging the freewheel. Normally a freewheel has a lot of loose balls and tiny parts, and reassembly requires mechanic skill.

In the second case, it may be better to swap the freewheel, because they usually are very affordable. To remove a freewheel a special tool is required, a tool that normally only bike mechanics and bike shops have. The tool has splines that fit inside the center part of the freewheel and allow to spin it backwards. The tool should not be expensive though.

Consider that to properly diagnose which is causing the failure, the freewheel must be opened anyway. In some bike shops the wage they charge for "repairing" a freewheel may be higher than the price of a new one.

The same concepts apply to a freehub, since the ratcheting mechanism is very similar. However, changing a freehub is more expensive because the whole wheel has to be disassembled and re-laced.

What is the difference between a freewheel and a freehub? The location of the ratcheting mechanism. Freewheels contain a ratcheting mechanism inside the cogs, and are just screwed into the hub.
This link shows an image of a freewheel removed from the hub

Notice the threads in the hub and the rear of the freewheel and also the splines in the freewheel. These splines are for the removal tool.

Cassettes on the contrary are a single unit with no mechanism, the ratchet instead is placed in the hub. When the hub has a ratcheting mechanism it is called a freehub. In this case the cassette slides into splines in one side of the hub and held in place by a lockring.

Photo of a cassette removed from the hub

Notice the splines that transmit movement from the cogs to the "freebody", the part of the freehub that can spin backwards.

Following the next link for a very complete guide: Park Tools' guide to removal and installation of freewheels and cassettes


This answer is based on wanting faster gearing, higher ratios.

To go faster you need to have smaller/lower tooth count cogs on the rear cassette, or a larger chainring.   Or both.

There is a physical limit of about 13 teeth for a freewheel and 11 teeth for a cassette.   There are BMX bikes and folding bikes that can go as low as 9 and rarely 8 teeth, but they require special wheel hubs.  SO if you're already on an 11 tooth small cof on your cassette, the only option is to upsize the front chainring.

Your main problem is clearance for a larger chainring.  Firstly it has to clear the right-side chainstay.  If that doesn't fit then you're out of luck.  Start with a cardboard template to see how much lager a chainring you could fit.

Then check clearance in all other directions - your breakover clearance (how close you are to the ground) will decrease.   Your front wheel will probably clear things, because it has to clear the pedal when in the forward position.  Upwards should be fine, but depending on your frame check all possible.

If your existing chainring is rivetted onto the crank spider then you're stuck, and will have to buy a new crankset.

Otherwise you'll need to find the BCD of your existing chainring.  Take it off  and print this PDF at 100%  then compare.  You will get an answer like 64, 88, 94, 96, 102, 104, 120.  If it doesn't match, check your printout was 100% scale.

Then buy the biggest chainring that will fit, that has the same BCD as your existing crank-spider.

Finally you'll need to add more links to your chain, so just buy one or two new ones.


I would add to the already existing answers some of the thoughts that come to me as a bike user.

For me using a bicycle is a mean to prevent getting out of shape. Using an electrical bike would be like going hiking with a car or elevator. This applies for a lot of my friends riding bikes.

Some of my colleagues complimented me on the fact that I exercise daily by riding to work. In the same register, I expect the opposite reaction for riding an electrical bike, as it would point the user out as a lazy/weak person, unwilling/unable to do any effort. Not saying it's true or right to be judged, but people often live by what others think about them (the coolness factor). you may get coolness points in the gadget section, but it's a different group of people that will compliment you on that. So it depends on where you want to position yourself.

A cheap bicycle is something you can easily toss in some corner when reaching a destination (edit: and of course diligently chain it up), without too much worry regarding theft. Can't do the same (with peace of mind) with an electrical bike.

Depending on where you live, using a cheap (second-hand, maybe) bicycle for two to three months already pays for the bike itself, by saving on transport costs. With an electrical bike, there is a steep initial investment, and the ROI is spread over a much longer term.

Electrical bikes are heavy and not so easy to maneuver in tight spaces where you need to carry them (like stairs). If they are light usually they are very expensive.

Finally there is the same concern as for electrical cars: will the charge last for the whole trip? If not, you'll have to pedal-drive a lot of additional mass accounting for the motor and battery.


Typically you will find a nipple on the hub that allows you to drain out the gear oil and then replace with new fresh oil which greases the gears. The placement and instructions for doing this depend largely on the type and brand.


Is it OK for a child's bike to have a radially-laced rear wheel?

For a kids bike where the rider weight is under 25 kilograms / 50 pounds a radial spoked wheel is fine.

I've been trying to clean up and true an old 12" steel wheel with radial spokes and I'm truly astonished how strong it is.  The spokes themselves are identical to normal bike spokes, just the length that is different.  The cross sectional area is the same.

The rim is normally the same profile as a bigger wheel too, just with more curve on it.  This also contributes to the smaller wheel's overall strength.

I'd say a 16" would be fine, but a 20" and above should be properly laced.
If the rider is... over 25 kilos then perhaps a cheap wheel is inappropriate.
The rider will probably outgrow the bike frame in height before they get too heavy for it.


Mixing Ultegra or 105 left crankarm with Shimano Sora support

Almost every Sora crankset from the past six years will be compatible with either a 105 or Ultegra non-driveside crankarm. To check if your crankset is compatible, you need to see if it's a hollowtech II model. These have the 24mm spindle attached to the driveside crankarm, while the non-driveside arm is then mounted using two bolts and a cap on the end of the spindle once the crankset has been put into the bike.

The Shimano Hollowtech II page here should help you identify whether your crankset is Hollowtech II. If it is, then you're safe to order that power meter, because it will fit just fine.


Here is a bike with the same logo (looks to be older than the bike in the original post) and information on the brand.

Cycles C.N.C. is a fairly obscure French brand that hand made exquisite custom bicycles for over fifty years, starting in the 1930’s.

later

C.N.C. began life in 1936 as The Societe Fletcher-Ducret, owned by Raymond Fletcher. It was a small shop in Paris located at 112 Boulevard de la Chapelle. They had a small retail trade, but made most of its money making special frames for many French professional riders.  Most of these custom bicycles were re-badged with the make of the company that sponsored the riders’ teams. Fletcher also suppied the top riders of quite a few of the eastern-bloc countries in the 50s through to the 70s, including Russia and Poland.

No one seems to have any idea of what the abbreviation stands for. It is believed that the Special-CNC frames were the very top of the range, possibly custom frames, hand-brazed by one of the top three builders employed by the company.  One of these builders was Rene Andre, a noted “constructeur” and contemporary of Rene Herse who also built bespoke bicycles under his own name.
DJCATNAP.COM

In another article:
classicredezvous.com

Comptoirs National du Cycle
Warehouse and workshop  at No. 42 Boulevard de Bercy, Paris

...cycle empire being owned by the firm Ste Fletcher-Ducret, which also owned the brands Chalpait and Thomann... though these two were later used to market the firm's 'everyday bikes'... was one of the capital city's cycling gems in the 1940s through to the 70s and, to a lesser extent into the 70s and 80s. The company is still registered, but no longer trades in bikes."


Shimano Deore front derailleur occasionally sticking

Put some chain lube (Triflow ftw) on the pivot points of the derailleur and go through its full range of motion a few times. You should start feeling a big difference. Also, you may find replacing your cables and housing to be beneficial - very easy to do on your own and relatively cheap to be done at any local bike shop.

Tip: WD-40 is not good for bike components. Use it to free up rusted screws- that's it.


Ultrasonic cleaner advice, for cleaning chains before waxing

Some notes from my experience:

If you are in a 220-240 volt country avoid the cheap Chinese cleaners, they are designed for 110 volts and remove a rectification diode as a hack to make it work on higher voltage.  This doesn't work well as the peak voltages are still higher and the output transistors fail.

Secondly, I found ultrasonic cleaning in just water and soap is nowhere near as effective as using a solvent.  I use kerosene, however its very smelly so I only use it outdoors, but it does clean everything well.

Lastly, I haven't noticed much increase in chain life vs just wiping with a rag and oiling the rollers.  Because of this I don't bother ultrasonic cleaning chains unless I am cleaning something else like a cassette.  My theory is the oil aids in flowing out contaminants in the rollers but I have no evidence to back this up.


Will a threaded post rim brake pad fit my brakes which take a thread-less post pad?

No it won't work well, I would not try it either... is injury worth saving a few dollars? Why not just buy the compatible parts?


30 lb Geared Bicycle vs 20 lb Single Speed, Which Is Faster for Commuting?

To answer this question you have to factor in all the specifics of your commute. In particular those are (including yours for completeness):

Length of your commute (in time - distance is less relevant).
Steepness of ascends (and descents if you accelerate down-hill).
Overall 'windiness' of your city.
Number of full stops and slow-downs you have to do (due to corners, crossings and traffic lights).
Your physical strength and general fitness.
Amount of time you are willing and able to spend maintaining your bike.

Number (1)2-5 need to be considered when choosing your gearing. If the ascends are steep (or you have expect strong headwinds often) you'd need to run a smaller gearing. That would enable you to power through the ascends and accelerate quickly - but it would also limit your top-speed. Also your long-time endurance would be worse on a high-cadence gear-setup.

Meaning: in such conditions it would probably be better to ride a couple of gears. 200%-300% difference should suffice - a range that you cat get out of a small road-race cassette.

If in turn your commute consists of shallow ascends and descends, and you pack enough strength to decently accelerate the gear-ratio you'd want to be running during your average commuting speed - then you can do just fine on a single-speed bike. I rode a commute of 27km (~17mi) on a single-speed bike for years without trouble.

If you're still undecided you might want to consider my point 6. Maintenance can be a hassle, costing time and money. But it is not necessarily much more expensive on a geared bike. On a single-speed bike you have much higher wear on your chain ring and the sprocket, due to the higher torque you put into your drive-train. On a geared bike that wear is considerably lower, since you can down-shift to accelerate, and it is spread over a number of sprockets instead of just one.

My personal choice for commuting: Internaly geared hubs

You can combine both of those upsides by running an internally geared hub. Something like the Shimano Alfine 8 should be more than enough for all commutes, and doesn’t cost more than most other geared drive-trains. It’s insanely durable and needs very little maintenance. I rode one for approximately 25-30000 km (including a technical trans-Alps tour with 20000 vertical meters) and it’s still going strong in my daily-driver commuting MTB. Of course those upsides are bought with a little lower transmission efficiency and a  higher weight. But that shouldn’t be to bad for a commuter. Plus you get instant-shifting capabilities – even without pedaling! This is something I grew quite fond of, because it enables me to brake and shift later – makes it easier to keep the speed high.


Boost 148 and 110 standard specification

MTBR has a pretty good write up about the technical aspect of it that can be seen HERE
From that article come these two technical drawings.

Boost 148 adds 3mm of spacing on each side of the hub. But unlike the 3.5mm difference from 135mm to 142mm, Boost 148 sees an increase in flange spacing, not just axle endcap width.
Boost 110 uses a 15mm thru axle and moves hub flanges outboard by 5mm when compared to 100mm hub standards. This 5mm outboard movement affects the spoke bracing in the same way as the 3mm shift on 148mm rear hubs, increasing spoke angles and creating, “the stiffness of a 26” wheel” in the front as well.
Now here comes the tricky part. With these minor shifts in flange spacing, the brake rotor mount location and the freehub body spacing have to be taken into consideration. Everything is shifted slightly outwards. So newer forks with the Boost 110 standard have also been designed to account for a shift in rotor and caliper location. That’s why Boost 110 is actually different than the 110x20mm thru axle standard that already exists. The 110x20mm hubs seen on bigger forks still have the same rotor mounting as a 100x15mm hub
Rotor shift is simpler than freehub body shift, because now with Boost 148 the chainline has been altered by 3mm. With a 3mm increase in chainline, it is necessary to move the chainrings outboard by 3mm as well. Luckily this 3mm shift can be accomplished with a redesigned crank arm spider. The Q-factor of the crankset and the BB width remain the same. For these reasons we will now see the introduction of Boost 148 specific cranksets that are necessary to achieve proper chainline.
With the shift outwards, the frame is afforded more clearance, which then allows the frame designer more tire clearance and will maintain a short chainstay.


Jockey pulley (upper jockey wheel) suddenly not engaging with the chain when in the three largest (easiest) cogs on the big ring only

It would help if you could post a photograph, but what I'm picturing from your description is that when you shift onto any of the three largest cogs in the back while you're on the large chainring the derailleur cage is pulled almost horizontal and the jockey wheel disengaged from the chain.

To me, this sounds like your chain is too short. Since chains don't magically shrink what I think happened was that when you put the wheel back on the bike you pulled it further back in the dropouts than its original position and now the chain has farther to go. So, I think all you would need to do is to move the wheel forward in the dropouts.

All of this assumes that you have horizontal dropouts, if you have vertical dropouts I'm completely wrong…


From Trek to Surly - advice on frame size

You could compare the geometries of the FX and the Cross Check. Matching the standover, 56cm matches. Comparing the effective top tube lengths, between 58cm and 60cm match.

Bottom line the geometries are different.

On another note, the FX doesn't seem to be a particularly high-end bike, so purchasing a complete Surly could possibly provide more economical than moving the parts to a new frame.


Are there any studies on fat burning in performance cyclists?

Look at the work of Jeff Volek https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=Jeff+Volek&btnG=
Rethinking fat as a fuel for endurance exercise  is one of his many papers, also Metabolic characteristics of keto-adapted ultra-endurance runners
He has also writen a book The Art and Science of Low Carbohydrate Performance
Low-carbohydrate diets for athletes: what evidence? Is likely to be cited by most recent papers.
These days most of his work is in Type2 diabetes, hence I dont' think he has published much on sport since his book.  Some of his sport research was done with static bikes using
professional long distance cycleists.
Ignore any research that had people on a low carb high fat diet for less then a few weeks before measuring performance as it is a common error other researchers make.


Parking a 3-speed internal hub in 2nd gear permanently

In the 45 minutes since I posted this question, I have developed an elegant workaround using a simple device:

I stuck a pebble in the bellcrank.

Most folks here probably won't be surprised by this solution, but I'll elaborate on how I came to it for the sake of future searchers who might be internal hub noobs like me.

In fiddling with the push rod, I determined that since I have three gears, it probably has three positions: all the way in, all the way out, and... somewhere in between. I took a wild guess that second gear would be the "somewhere in between" gear. I figured that "all the way out" was third gear, since that's the natural position the rod is in when there's nothing in place to push it anywhere else, and 3rd is the gear I was stuck in.

I fiddled with the bellcrank some more - putting it back together, seeing what pieces would push on what if it were working properly - and determined that when the bike is in third gear, the head of the push rod butts right up against the inside of the part of the bellcrank that screws onto the threaded axle rod thingy. (Terminology is hard.) So: I need a way to push the rod into the halfway position while the bellcrank is screwed on in order to jam the system into second gear.

Enter the pebble. I found one in my yard that seemed to be the right size, dropped it into the bellcrank and put it back on the bike. Voila: the push rod is stuck in the "somewhere in the middle" position. I am effectively parked permanently in second gear. (Well, I can also shift into third gear if needed: I just have to stop, dismount, and unscrew the bellcrank a little. If I had a second pebble of equal size I could probably get myself into first gear, too!)

So, this is my workable, cheap (free!) solution. I will leave this question open for a while though because I am hoping someone has something a little less bush-league to suggest!


What tips do you have for making temporary "get me home" repairs?

You should also have a survival bag, mobile phone, whistle, torch and small first aid kit as well as a map and compass.  Remember it may be you that is broken not your bike!


it could be a 2001, i'm rebuilding a rare one, came with a threaded Icon Air Rail fork, but i used a threaded to non threaded stem converter :D


Suggestions for outdoor commercial (security/parking) stands

It is hard to beat a “Sheffield” stand, as they make it easy to lock the bike and don’t bend your wheels if the bike is knocked over.

Cambridge Cycling Campaign did a good write up on the options.


Disk Brake shudder felt through fork and frame

First thing, assess your headset. A loose headset allows feeble vibrations to make the bike shudder. This  tutorial over at Art's Cyclery will guide you through the process of taking care of it: all you'll need is a medium sized Allen Key.

If the headset looks just fine, it's time you get to your break calliper and rotor. I recommend that you sand your rotor and break pads a bit (until they look nice and smooth) with a medium grit sandpaper, wipe them down with some 90% v/v isopropyl alcohol nicely, reconfigure and bed them in. Also make sure that the calliper is aligned just right, if the calliper isn't approximately parallel to the rotor, it can make the thing happen. I would recommend using the business card method to align the calliper. Doing this will almost certainly cure the bike of the issue.
I hope this helps. :)

--

Edit: Also make sure that your pads have enough braking material on them before reconfiguring them.


Chain not sliding into casette perfectly

By definition, if the chain is not running on all cassette sprockets properly, the indexing and/or limits are not properly adjusted. Low limit setting being off would be my guess.

Run through the full indexing adjustment procedure. Park Tool Company has the best instruction video.

You can check the derailleur hanger by lifting up the rear wheel and looking down a line from the derailleur cage to the chainrings. The cage should look parallel to the rings.


Is it ethical to ride with races without being part of them?

Unethical, because you're imposing costs on the organisers anyway. Apart from the obvious "if you get hurt they're going to help you", they almost always face costs per participant and often have a limit on numbers. Violate those limits and the organisers will have problems.

You're also causing wear and tear on the track, equipment and marshals. You can't pretend that away by saying "other people do it too"... yes, and they paid for the privilege. You're stealing it. Not really ethical IMO.

This is another case where your exact marginal impact is low, but at some point one more increment like that will get the race cancelled or refused permission to do it again.

The other thing is that if you are involved in an incident and are deemed to be at fault, you will not be insured. The race insurance won't cover you (obviously), but whatever insurance you have almost certainly has a an illegal activity exclusion. They'd most likely leave it to you to show that what you were doing was lawful. But since most races take place on temporarily closed areas, that would be hard. They close the area specifically to people like you. For exactly that reason.


How can I fix brake pads being too tight even after pushing the pistons back in?

My avid brakes had the same problem and it was due to too much fluid in the system, to solve the problem :

Remove the pads and keep them away from any oil (fluid).
Unscrew the bleed screw a little and put a towel on it
Push the calipers back completely

4.Clean calipers well before reinstalling pads.

Be aware that the amount of fluid that will exit should be a drop or a little bit more.
Let too much fluid exit and you will have to rebleed them, so do it gradually.

This is a common problem on new avid sram brakes.


This is a standard English manufactured sport bike probably from the mid-60's.

It used freewheel type hubs and from what I can see you appear to have modified the rear wheel with a seven speed freewheel. The original rear triangle spacing was probably 125 mm and the seven speed uses a 127 mm spacing. Usually someone would re-space the rear triangle and put a spacer on the right side of the axle and normally they would not re-center the rim. This would cause the wheel to be slightly off-center in the stays. It usually had no deleterious effect.12speed


When do I know the drum brake is at the end of life and needs replacement?

As the drum brake surface wears down, you will have to keep tightening the adjustment bolt so that the drum lever arm moves forward (towards the front of the bike) more and more.  Sheldon has some images and explanation that you might want look at:

Drum Brake Adjustment
When brakes are new they may have to be adjusted frequently (until the shoes have become properly bedded in).
With cable-operated brakes the small locknut (A in the diagram) is first Loosened off and then the knurled adjuster (B in diagram) is tightened until the brake shoes are felt to be rubbing on the inner surface of the hub shell. The adjuster is then Loosened just enough to allow the wheel to revolve without friction, and the locknut is tightened up again.

If your bike does not have an adjustment nut/bolt at the drum, you will have to undo the retaining nut, cinch up some more brake cable, and tighten it back up.
You know you've used up all of your brake surface when:

The brakes are making a horrible grinding or scraping sound and/or aren't working efficiently (note: they might be just glazed so you should take them apart and see if the brake surface is glazed; if so, deglaze it with sandpaper)
The brake drum lever arm is almost all the way forward and is limiting your braking performance
There's a little arrow or other indicator on some brake drums by the brake lever arm which indicates that the brake lever arm is fully extended and worn
You've taken the outer housing off and you can visually see that the brake surface is worn down. The brake specifications should give you the minimum brake bed material that you need, otherwise I'd use about ~2 mm as a general rule.

Because of their larger surface area and because they are in the rear, drum brakes tend to have a longer life compared to front brakes.
Example
From Wikimedia commons is this image of a panasonic drum brake (front and rear). This brake has an adjustment nut/ferrule where the brake cable housing meets the brake. Note that the brake lever arm is pointing slightly backwards (towards the rear of the bike).  You should check for wear if you're at the point that you've back the adjustment out so much that the brake arm lever is pointing forward even when the brakes aren't applied.


Using an 8 speed cassette on an 10-11 speed Tiagra FH-RS400

The hub for 8 to 10 speed are the same. You are good to go. You should not need any spacer for them.

However, if you mean this hub https://bike.shimano.com/en-US/product/component/tiagra-4700/FH-RS400.html they say it is a 10/11 speed hub and hence you need a (1.85 mm, as mentioned in a comment) spacer for 8 to 10 speed for this one. Those are included by some shops.

Because it is a Shimano hub you can also verify the compatibility in the official chart https://productinfo.shimano.com/#/com?cid=C-453&acid=C-454

A similar hub which is simply 8/9/10 speed would be (Sora) FH-RS300. It could also be cheaper.


is a SRAM XX 1 crankset compatible with an XT 8000 BB

Not at all. GXP cranks need a left bearing with a 22mm ID, not 24 like Shimano.


Chain rubs against frame when in smallest rear cog

Sometimes things like this happen when newer generation components are put on older frames. When Campy 10 first came out, I remember some frames doing it. However, that was usually from hitting the end of a chainstay or seatstay that wasn't offset flat enough with the inside face of the dropout.
Your picture shows the chain rubbing against the flat surface of the dropout, or what would normally be made as a flat surface, which is odd. Three things that come to mind are the dropout is trying to be flat but isn't, the locknut contact area got worn down or made badly somehow, or the hub and/or cassette is put together wrong. Those are the first things to check.
There are QR and thru axle versions of the frame, and you don't say which you have. There's no QR nut visible AFAIC so I'll assume thru.
It's not clear from the image whether knocking down the relevant dropout surfaces a bit would do it, but that could be one approach. I would let a ti framebuilder or the manufacturer evaluate that unless you're feeling daring. There's also the notion of slightly building up the axle contact surfaces (you'd want to do it symmetrically), i.e. if it were a QR frame and you were okay with the judgment call of increasing the OLD by the needed amount, probably like 1mm total, you could bond in some .5mm ground stainless round M10 shims and then trim them down once set to become part of the dropout. Doing the same would likely not be as straightforward with a thru axle, and you can't easily check the dropout alignment before you start, which is not ideal, but it may be possible.
Edit in response to comment:
Personally, the first thing I would do to evaluate a solution based on adding a spacer or spacers is measure the current rear end spacing and the dropout alignment. While at it you could get an exact measure of the hub OLD, which is less relevant because wheels get switched, but you may have an idea of how long/often it's going to be run with the wheel you've got.
Adding spacer(s) and then putting the wheel back in splays open the frame. What happens when you close the QR is it then squashes the dropouts and axle together to be in line anyway. This creates flexion (I think I'm using the term right) in the dropouts and/or axle. Depending on how stiff, strong, and ductile those parts are, the result can be fatigue cracking in the dropout or axle, or flex in the axle that can cause bearing misalignment and resultant drag, or harmless flex in the dropouts.
A lot bikes in the world have, for example, thin dropouts made of a high-ductility steel like 1020, which is fancy talk for melted Chevys. Do something like this on a bike like that and the dropouts will flex to accommodate and you'll almost certainly never see an ill effect. A recent ti frame with what look like thick dropouts, plus presumably some kind of modern, stiff, oversized aluminum axle will be different. I'd be more concerned about fatigue failure in the dropouts. And if you do wind up with axle flex, that can be pretty bad too.
That is not all to say it couldn't be reasonable under any circumstance. But you need to judge it in light of the existing spacing and dropout alignment as well as how much gap you intend to add. It's common for spacing and dropout alignment to be imperfect as-is. So you want to know it if for example you're taking the dropout alignment in the direction you'll be adding splay from iffy to worse or perfect to iffy or whatever. And same with the spacing. Say it happens to be 136mm with perfect dropout alignment now; if you add 1mm you're actually making it better, because you're presently adding the same sort of misalignment and flex in reverse when you clamp down on your 135. (I'm assuming it's a 135 rear end, substitute 131 and 130 for the above numbers if not.) But if it were 133 with perfect dropout alignment now, the 1mm added means something different. The point is that the state it's in now is really what the whole conversation is about in terms of whether this is a good idea.
Note that driveside dropouts or dropout-chainstay connections are a major place that frames naturally fatigue out even if everything about their construction is great.
As for what to actually do, I, again personally, would never add a free-floating spacer there. Yes it could be a way to make the bike physically work. To me it would feel like janking up a nice bike. It would also feel like janking up a nice bike to only add a drive side spacer and thus either accept the wheel being misaligned in the frame or having to run a wheel that's custom-dished for the frame in the direction that gives up non-drive-side spoke tension. But say you get your M10 ground SS 0.5mm round shims and determine that one is all it takes, which appears likely. There are spacing and dropout alignment situations where bonding on one per side could then be either totally fine or a compromise that never amounts to anything. You could then test before doing it by putting them on and penduluming the wheel with the chain disconnected, and getting a feel for what's happening with the dropouts by tactile observation when you close the QR. (What I found doing this would inform by answer to the question of whether I'd do it if the dropout alignment and spacing were both perfect.)
I would personally be far more curious about first seeing if a ti builder might be into knocking down the rubby areas with a dynafile or whatever.


What's a good setup for an experienced but rusty cyclist training for his first triathlon?

You probably don't want to spring for a specific time trial bike straight out of the gate - you might hate the triathlon experience, for one thing! Given that you're planning on using the bike after this events, albeit possibly with other events down the pipe, I'd be looking for something that you can get the best use of after the event.

So a road bike would seem to be the better bet - possible with a set of clip-on tri-bars; while not everyone gets on with them (not all road bike/ride combinations work with the correct geometry) they are generally considered faster - you're in definitely in a drag-reducing pose and they force you to stay still a lot more, which is better, too.

A tri-cross sounds, erm, intriguing. A time trial/triathlon bike will be set up to encourage a mono-position with speed, probably with a longer, lower back/body position. A cross bike generally has more clearance and encourages a head position almost over the bars, a shorter top tube and more clearance to enable better control on a uncertain terrain - these would seem to conflict ...

Over the years I've seen triathlons done on many types of bikes - even sit-up-and-beg shopping bikes with a basket! You won't be doing it for speed, but you'll finish.

Use the bike that you would think you'll get use off after the event. This will result in several things:

you'll have spent your money on something you'll use
you'll finish the triathlon
you'll have set yourself a (beatable) target time for the next event
you're going to be in a much better position in a few months, after the event and after a bit more training, to know what'll work for you.

Then get all of the above: once you start racing, commuting, shopping and training on the bike you'll be able to justify a time trial, commuter, road and MTB ... and even then you'll probably find another type you're missing!


What are the steps required to revert from STI shifters to friction shifters?

Basically you may drop steps 2, 3 and 6.  You'll just remove the shifter cables from the STI levers. It might not please the aesthetes but it will work. If the STI levers have the shifter cables run through external housings you remove these as well. If the housings run under the tape, you leave them alone, you just cut them where they come out from under the tape. (At this point it is a good idea to buy a cable and housing cutter which is a very useful tool that avoids a lot of messy and badly cut brake/shifter cables and housings.)

The downside for keeping the STI levers is that the combined levers are heavier and have the unnecessary side-ways freedom of movement. But that's fine if it doesn't bother you. If you find out that this is unnerving then you may switch to regular brake levers.

The day you want to change the tape, you may acquire a pair of regular brake levers and put them on the bar.

Edit: No, you can't keep the shifting cables running from the bar just through the friction shifters. You'll need to remove them and rethread them directly through the friction shifters.


Is there a specific grease for titanium frames?

For titanium frames, it is best to use a copper paste grease. You need to do so anywhere there is metal on metal contact, especially if it is aluminum to titanium contact.

Normal grease is not enough to prevent the accelerated oxidation and bonding that occurs between totanium and other metals.


will increasing cadence ability hurt my climbing strength?

The general advice is that we should aim at 90 for an average cadence, and pushing slower than that can produce knee pain and injuries, and back pain and injuries.

However, everyone has their own best cadence. For example, I have not raced and find 110rpm is good for me on a flat-ish ride. My brother who has raced stays at around 120rpm on the same terrain. I find I'm changing gears if my cadence drops to 100, unless I'm on a long hill greater than about 6%, when I drop below 100rpm with my 39x26 lowest gear.

Climbing ability is a combination of your strength, endurance, and the gearing. Cadence enables the delivery of higher power. As one example, look at runners - sprinters aim for high step rates. For a cycling example, look at sprinters on the track or at the end of a road race. They also aim for high cadence. Going back to my personal examples, I can push to 180rpm in a sprint, and my brother passes 200rpm. Cadence is where the power is. If the cadence is too low on a hill, then we need better gearing to get back to where the power is.

Cadence is also where the muscular endurance is. For a given speed, at 50rpm your legs are pushing twice as hard as my legs at 100rpm (all else being equal). So my legs are generating half the power per revolution than yours. Cutting a long story short, the legs working harder will tire more quickly.

Cadence is supported by your cardiovascular capacity. A good cadence is where your performance is within your Aerobic capacity. This is essential for endurance.

So, to answer your headline question -no, increased cadence should not hurt your climbing strength.

The reason for the caveat is your mention of interval training. Interval training is about increasing your power and lactate threshold, not cadence. It does this by going faster for short periods, requiring you to work at or above your aerobic capacity. While valuable for developing endurance, it is not about training for cadence. Cadence training requires pushing a light load (for example rollers or riding behind or scooter) for long periods.

BTW, using the calculations provided by R Chung in this answer, suggest that your sprint on a 12% hill is producing close to 2kW. If your figures are correct, then that suggests you should be racing :-)


The current Ultegra chain rings are in fact physically compatible with the 105. They do not look good on the 105 crank, however, because when Shimano redesigned the Ultegra and DuraAce level cranks to their Hollowtech II design, the made the chain rings hollow as well.
Th point where the chain ring meets the crank arm is noticeably thicker, and shaped quite different on the Ultegra chain ring and crank, compared to the 105.
This is the 105 FC-5700, which is newer than your FC-5600.

This is the Ultegra FC-6700, which compares to the FC-5700.

See the extra shape and thickness where the chain ring bolts are? That is why they do not list Ultegra rings as compatible with 105.
You can physically bolt them up, and they will work, but they look bad, and you don't get most of the benefits of the Ultegra ring, (mainly added stiffness), without the whole crank.
A set of Ultegra rings will cost 150 dollars, and a whole crankset, including rings will be around 250 dollars, so it might be worth just doing th whole crank, if you're interested n upgrade.
Otherwise, just stick with the 105.


Shimano RD TX55 Tourney TX 6/7 Speed Compatibility

Edit: First question, why did you replace the derailleur?

Rear derailleurs don't really care about # of speeds - its the shifters which change the cable pull to move them around (so mixing shimano and sram can cause problems due to different amounts of cable pull). By RD not aligned with gears, do you mean the hanger / cage are bent? If so, go to your LBS and get them to unbend it / replace the hanger. If the rear derailleur is in good condition, you just need to adjust the cable (assuming its in good condition) to be taut when in the smallest cog (I lightly use pliers for this - make sure that the cable is actually being held in place) and then use the adjustment screws.

Have you adjusted your high low limit stops and indexing adjustment and btension?
See http://sheldonbrown.com/derailer-adjustment.html for an overview (or one of the various youtube videos on doing this)
http://www.parktool.com/blog/repair-help/rear-derailler-adjustments-derailleur

Also see the thread here: What are the most common causes for hysteresis in the rear derailler?


The best shop rags I have ever used are blue medical operating room towels. They are much stronger than old clothes. They are intended to be thrown away, but I wash them and use 'em again.

However, I don't know where to get them. Maybe if you have an O.R. doctor or nurse in the family.

(I also use these to clean the kitchen, to wipe up spilled soup, to wash a car or bike, as hot pads, and as napkins. I put a damp one under the cutting board to make it stable.)


How do I calculate the diameter of a chainring from the number of teeth?

A chainring is an n-sided regular polygon where n is the number of teeth.  The side length s of the polygon is the distance from tip-to-tip of each chainring tooth.
The formula for radius of a regular polygon is:

(source: mathopenref.com)
Using zenbike's 12.75mm above for s, we get 107.61 for the radius, or 215.22mm for the diameter, which is very close to his approximation.
Comparing the two formulas shows that the length term, as expected, can be eliminated. This leaves us with:
1 / sin( pi / n ) vs. n / pi
For large n, those terms converge, introducing an error of just .12mm when n=53. It's a bit larger as n gets smaller, differing by .64mm for n=11.
For all practical purposes, I'd just use s * n / pi, even for the smallest cog you'll come across it'll be within a millimeter.


Since you guys have all been so helpful, I thought you'd like to hear the answer to this mystery.

The bike was indeed stolen. I was able to find the rightful owner.

The frame was custom made of stainless steel in Capetown South Africa by BouwerWorks. (So, the 'B' did mean something). This builder has apparently stopped making frames, or else, has stopped any kind of marketing. His website is down. But, I found his Pinterest Board  (look at the profile pic) and also found an article on a design site with info.

Most of all, I'm happy that the owner is getting his bike back.
Thanks again.

https://www.designindaba.com/articles/creative-work/building-unique-bicycles-his-spare-time?fbclid=IwAR2xckegUtatQZrxhAEeD_VWCiPDWp-NWsHv1UDGnRpeK5hQ41KtNg7BBCs

Adding a bit more info. SO, I found the owner first and that is how I got revelation on the frame. I have a friend that runs a local charity. Village Wrench - They go into neighborhoods on weekends and do free bike repair for those who might have no other options - they do a mentorship program to teach people (mostly kids/teens) how to work on bikes, learn leadership, learn job skills, earn their own bike, etc. -- I sent him a message with photos. He suggested a few other people. One of them knew the owner (who moved here after spending time in Capetown) and was aware the bike had been stolen. After we connected, he told me the story of the bike and how it was made. With that info, I was able to find the BouwerWorks info online. A bike is only worth what someone will pay for it. But Bouwer regularly sold his frames $3,000 and up. So this owner was happy to reimburse me the $175 I spent. That low price is the main reason I suspected it was stolen. I provided the name of the person who stole the bike. A police report was filed a month ago. But I don't think the owner is going to bother with pressing charges at this point.


Linseed oil application to the inside of a steel frame

The preferred way to do this is to use something like JP Weigle Framesaver. This is an aerosol so you're more likely to get the product in more places which should be protected. And it will dry much quicker (though it has been known to make seat posts somewhat prone to slipping).

However, companies like Surly still state boiled linseed oil and motor fogging oil are  acceptable ways to protect the inside of the frame from rusting. John Allen also discusses a product called Boeshield T9.

You're only saving about 5 bucks probably by using boiled linseed oil, so I don't see the point in preferring it unless you already have it / have some problems with aerosols.


One stripped post mount on suspension fork

You might consider tapping this thread back out if you have a decent tap-and-die set.  Otherwise, a heli-coil should work for this application.  I would be more concerned with a heli-coil if you were using it on a post-bolt that would experience tensile stress--that is, "pull-out" force.  This bolt will be under mostly shear-stress, which means that the majority of the strength will be derived from the body of the post rather than from the threads.

I'm not an engineer--engineers, please correct me--but this is what my thinking is when I fix a broken piece of metal in a situation like yours.

If you are a little paranoid, you might goop the bolt threads with some JB Weld before threading them into the heli-coil.  This will add a little tensile strength and piece of mind, but should be pretty easy to break out with a breaker-bar if and when you choose to remove the part.

Note also that, in my experience, any use of a heli-coil or JB weld has the potential to be an "ultimate" fix.  That is, once it's fixed... it's fixed for all practical purposes and subject to failure if "fixed" again in the same place.  I might do this to my 90's Rockhopper, but I don't suggest it for your 2011 Santa Cruz Blur that you plan to change everything out on next season.

Short answer:  With the sort of riding you are suggesting, I would do the fix you are suggesting on my beater mountain bike.  On my high-end down-hill ride... I would take it to a frame builder and have the post replaced.


Can cyclists legally ride on the sidewalk?

Safety

In general, riding on the sidewalk is more dangerous than riding on the road. There's higher risk from cars coming out of driveways than cars overtaking you from behind. Generally cars aren't looking for anything on a sidewalk moving more than about 3-4 mph, there's often visual obstacles (trees, sign posts, etc) so you're likely to be invisible to cars that might turn into you. Going against the direction of traffic gives everybody a bit less time to react to anything going wrong and puts you on the side car drivers typically aren't looking in.

If it's legal on a specific block, I might ride slowly (5mph, 8mph tops) for a block on the sidewalk to get to a spot where I can get onto the road properly. But be extra-aware of all driveways and side streets. I might also ride on the sidewalk for under 10 feet when coming off of the road via a driveway or curb cut in order to stop and lock up my bike.

Check your local laws

There is no statewide California law prohibiting operating a bicycle on a sidewalk, however California Vehicle Code Section 21206 allows local (county, city, etc) governments to regulate operation of bicycles on pedestrian facilities.

In other words, there is no California-wide answer to the legality. It may be illegal in the specific area you were riding, but legal on the next block over or legal on the other side of the street.

In the city I live in (in California), it's illegal in two defined "downtown" areas, but otherwise legal. In some cities it's illegal to ride on the sidewalk anywhere in the city.

Or perhaps it's simpler to explain that California Vehicle Code Section 21650(g) explicitly allows riding on sidewalks and through crosswalks, unless prohibited by local ordinance.


Should I make any adjustments for steep bumpy down hills?

The adjustment needed is to lower your seat. Your seat is currently set for road riding where pedaling efficiency is important.

The idea when Mountain biking is to maintain the center of gravity over the Bottom bracket. As the down hill gets steeper, you need to shift weight back to achieve this, as the uphill gets steeper, move weight forward.  The seat post in a normal climb position prevents the required weight shift.

The weight shift has to be done by moving the whole torso. Assume the 'Attack position' (google is your friend) - This correct riding position is arms are bent, elbows out  (ideally forming a C when looking head on to the rider) and torso is relatively level, legs straight but knees not locked (i.e. very slightly bent - knees bent is common advice but gets miss interpreted).

(IMHO his knees are bent too much. This amount of bend requires a lot more effort in the quads than needed.)


Do mechanical disc brakes suffer from heat-induced fade?

From my experience, the answer is no. I have been cycling across the Great Glen and have no problem with mechanical disc brake.

My bike was moderately loaded with camping equipment. So the load (including me 70 kg) was around 110 kg or 242 lbs. There were continuous downhill sections but the brake works fine, thankfully.

From a scientific stand-point, there are three types of fade

Green fade - caused by resin boiling off of new pads
Fluid fade - brake fluid boiling and system losing pressure
Pad fade - pad overheats and loses friction

Ignoring 1, 3rd cause starts to occur at much higher temperature and require time than 2nd cause (which occurs at around 120 oC for moderately contaminated mineral oil*). That is why you need to check your mineral oil before setting out on a trip.

Pad fade is the main factor in Mechanical Disc brake fade. Unless you are not braking heavily and continuously for more than 10-20 minutes, you are fine.
In number, if you are going down 20% gradient hill, braking continuously to keep your constant speed at 18 kmph (11 mph), the braking power is around 1078 Watts for 110 kg (bike+load+rider). That means, referring to **, you can safely brake
for hours, if not hundred of hours for the iceTech.

Refer

*http://www.epicbleedsolutions.com/blog/dot-brake-fluid-vs-mineral-oil/images/shell-dot-fluid-boiling-points.png

**http://cycle.shimano-eu.com/publish/content/global_cycle/en/nl/index/news_and_info/Velotech_Disc_Brake_Test.html


A mountain bike is not going to be inherently stronger.
If anything a larger frame triangle is stronger.
On a mountain bike you have a long seat post that is a point of failure.

I don't recall seeing weight limits posted for bikes.

Consider a touring bike as they are designed to handle a load.
Or an expedition bike.
I would go with a high quality steel or titanium bike.

Some wheels will post weight like Stans posts weight for some of the wheels.

And larger tires do take more weight.  You always see larger tires on touring bikes.  Weight = contact area X psi.  A larger tire generates a larger contact area with less deformation.  A larger tire protects the rims.  The wheel still must bear the weight but the rim is cushioned from that ding associated with pinch flat.

With light use I suspect those bikes would be OK.

From Trek up to 300 should be OK.
Is there a weight limit for your bikes

If you are targeting 300 lbs then consider some more expensive bikes. Like a Salsa Vaya or even more $ a Moots Routt 45.


Is there any way to save disk brake pads once they've gotten even a little bit of mineral oil on them?

The best approach I've seen in terms of producing non-mediocore results is heat them up with a heat gun until you can see the oil smoking up and maintain that heat until the smoke stops. You want to heat it through and minimize peak temperature, so let that inform your setting and distance.

This can work pretty well but I make no promises what the metallurgical side effects may be. It's an at your own risk thing only. That said it's a pretty common trick and I doubt there's much risk. And of course do this with good ventilation and with the pads in a vise, hanging on a cable, or some other way where they won't need to be handled until cool.

Things like sanding, degreasing etc really don't work because the whole problem is the material has some porosity.


The primary difference between the 2015 and the 2018 seems to be the availability of disc brakes. The decision will depend on how much you think the disc brakes will improve your ride quality. I would take both for a test ride and see if you can really feel the difference in braking quality. The discs may give you better braking in wet or muddy conditions especially if the bike is loaded for touring. A concern may be the availability of disc brake parts if you travel in very remote areas.


Pinch flats or snakebites are caused when the rim bottoms out and the tube gets pinched between the rim and the tire and punctures - usually 2 smallish holes 10mm (1/2 inch) apart, hence the name "snakebite" because that what it looks like.

The two holes (or a hole and a sign of damage close to it) are the tell tale sign - its rare to get a puncture from a foreign object causing two holes in quite the same pattern.

The cause is that the air pressure was not enough to prevent the tire collapsing to the point the tube is pinched. Usually a sign of too low tire pressure, but can happen when you hit something like a rock or pothole with a sharp edge.

Prevention depends on riding - for a road bike, more pressure (under-inflated tires are the main cause), and check pressure before every ride. Avoid potholes and such like. For heavy riders or bad roads, bigger tires and thicker, stronger tubes can help.  Mountain bikers have a different problem - often we want to run lower pressures for traction on rough ground - the very same ground that makes you susceptible to snakebites. Its not unknown to keep lowing pressure till you suffer snakebites, and bring them up a bit. There are also option for tubeless tires, which do not suffer snake bites (but can suffer bead separation if run too low pressure), and as for road bikes, bigger tires and thicker tubes.

Another preventative measure is to coat the tube with talcum power before installing it. The talcum acts as a lubricant, and allows the tube to move without tearing itself apart. I have used this method on my MTB for years and it seems to be effective as I have not had a snakebite for a long time.


Major differences between Hardtail and Full Suspension mtn bikes

It is as simple as full suspension feels like suspension on both wheels and hard tail feels like the front only.

Use the full suspension for more and bigger bumps.
Also for landing jumps.

The hard tail is lighter and the pedal action is more efficient.
The frame is stiffer laterally (more efficient).
The rear shock on a full suspension will absorb part of the pedal energy (very little as it is designed to minimize this).
For lighter bumps.
The tail will get bounced around (much) more than full suspension.
Bouncing a real wheel is typically not going to drop you but you are not getting traction.

You will typically see downhill riders on full suspension.

On single track it goes both ways.
Your preference and the nature of the single track.

Trials riders will ride hardtail.

Some tricks like a bunny hop are easier on a hardtail (I think).

If you are learning technique then I would go hard tail as it more forces you to pick a line.

If you want to bang through some ruff stuff then full suspension.

Tend to take harder falls on a full suspension as you can go faster on the bumps.
And when those bumps are rocks it hurts.
And when you ding a $1500 frame it stings.

If you are going to get full suspension then get a good one.

In looking at cost and weight of FRAME ONLY.
I am going to compare Niner as that is what I ride and what I know best.
Hard tail frame: Ross 9 large frame weighs 1,680g and retail list for $899
Soft tail frame: Jet 9 large frame weighs 2,980 and retail list is $1849
Now those are higher end frames and the difference is $1000 and 3 lbs
On the mid range the difference might be $400
Don't buy a low end full suspension!

My two cents:
Don't buy full suspension for your first mountain bike
Learn technique on a hard tail
There are lots of times when you going to want to ride a hard tail
Make it your second bike and be ready to spend some coin
The guys and girls riding a full suspension for what it is are good and are on $3000+ bikes

My three cents:
Upgrade your hard tail to tubeless and go 2.25 (or 2.4 in the rear if you can) in the rear
Not the same but at lower pressure you get less bounce (for NO weight)
And you get the grip of conforming to rocks and roots
And you get no pinch flats
For less weight than the full suspension


How to straighten a bent derailleur hanger?

Remove the derailleur and use an adjustable wrench to bend it back into shape on the bike. That way you can see when it's straight more easily. Remember to check both vertical alignment and fore-aft alignment. With 5/6/7 speed doing this by eye will be fine. You might get good enough for 8 speed, but with 9 and 10 speed you'll have to be lucky to get reliable shifting using this method. Those setups are just too fussy.

Bike shops have a derailleur hanger alignment tool that does this much more accurately by screwing into the derailleur mounting hole and letting you gauge position against the wheel rim. I've found that with 9 speed often a couple of millimetres at the rim can be the difference between smooth shifting and constant "not quite in gear" clicking in one or two gears.

Edit: this is a classic "trivial with the right tools, impossible otherwise" job on 9 and 10 speed systems. Put the bike in a mechanics workstand, attach the alignment tool, bend the hanger, reattach the derailleur, check the gears and it's done in 5 minutes. The bike shop will probably want to put in a new gear cable and housing for you (because otherwise if the shifting is less than perfect you might blame them rather than the friction in your old gear cable).

The fun part, BTW, is finding a replacement hanger if the bike manufacturer no longer stocks them. There are "clone" manufacturers but the catalog of available hangers is huge (often one bike model has different hangers in different years, so unless you know exactly which frame you have the label on the frame might not help much).


My first thought that with a new drive train this would be either:

A bent derailleur hanger
The rear shifter cable has an issue

As you have had the hanger replaced recently I would tend to think that it was likely that it is a cable issue.

The first thing I would do is inspect the cable and make sure it is moving freely in the housing and there is no fraying or bends and that the end caps are all seated well in the cable guides. The more likely thought (and timing for this would also seem right) is that the cable has stretched and this is the cause of the slippage under pressure. There are barrel adjusters on your shifters which allow you to fine tune the indexing between the cogs (the H and L screws set the outer limits). There are many different ways to do this but Park Tools provide a helpful guide here.

My assumption (without seeing it) is that a new RD would not need to replaced so soon unless something was visibly broken or bent beyond repair.


That model crank is listed as a current component in the Tourney range. See this page on the Shimano site: https://productinfo.shimano.com/#/lc/tourney/3x7

The key to square taper 3-piece cranks is the axle length of the bottom bracket. Different model cranks require a different axle length to get the correct chainline (distance of chainrings to center line of frame).

The Tourney TY501 crank is direct replacement, the TY801 requires a different bottom bracket axle length, so the bracket has to be replaced with the crank. You could also upgrade to a higher level Altus M311 crank but again that requires a different axle length

Shimano's specs are here if you want to check them out: https://productinfo.shimano.com/#/spec/MTB/Front%20Chainwheel. Search for 'FC-TY301' and look for the BB axle length row in the table.


Many saddlebags work with the German KLICKfix system. The KLICKfix system is a series of brackets including one that goes under the seat and another that goes on the seatpost. In my experience the one that goes on the seat rails is more durable and less wobbly. It also seems to be the one preferred by manufacturers of bags.

One interesting option are the bags made by Blackburn. They have a lifetime warranty on them - a quirk of the Blackburn company. Get one and it won't be throwaway.

Here is one they do for the Klickfix bracket, the Zayante large. It has an expanding main compartment, little pocket for valuables, loop for putting the light on, reflective trim and so on:

Here is the KLICKfix 'Contour' model with the other bracket type. This one is supposed to be aero:

I suggest you go to one of your better local bike shops and specifically look for bags with the KLICKfix adaptor, regardless of brand, they should have some. Ordering online can be tricky as you need to see the product first to see if you will be able to get your coat, tools and whatever else in there.

In former times (50 years ago) panniers were the rarity and saddlebags were the norm. I am a proud owner of an extremely retro saddlebag and I use it in preference to panniers.

I believe such bags are bigger than your current requirements, however, I mention that for others finding this question. There are smaller 'real saddlebags' and there are also brackets to go with them if you don't have saddlebag loops.

Another 'out there' solution you might want to look into is a handlebar-bag mounted behind the seat. Klickfix adaptors are available for the handlebar or the seatpost and you can put both brackets on if you want for marginal weight penalty. When you want to do a bit of map reading, eating, using the camera and so on, you can put the bag on the front, when you want lighter steering and better aero then you can put it on the back.

I don't think bike bags are a truly international product area, so the UK tip of 'Altura + Klickfix' probably is not what you would want to look for in the U.S.

In summary, the German 'Klickfix' brackets are brilliant, easy to use, well constructed and used by many different bag manufacturers. The under-seat bracket for 'saddle stuffer' bags is very good, for your requirements I would suggest having a look at what bags you can get that use them.


Do expedition bikes offer advantages over standard touring bikes?

You should find that on those bikes everything is a bit stronger and heavier than a standard touring bike. Not only are they expected to carry more weight, they're designed to be ridden into places where failures are more difficult to recover from. As well, because they're designed to be ridden off road they'll usually have a lower top tube for better stand-over height, and there are fewer compromises in building a frame like that with smaller wheels.

Smaller wheels are stronger than larger ones, mostly laterally but also weight-for-weight vertically (shorter circumference means more material per unit length). This is most obvious with the 306 and 406 wheels used on trikes, but applies also to larger wheels except that the differences are smaller. Larger wheels mean the axle is higher, but also the top of the fork crown and so on, so you're adding the change in diameter to the frame height, not the change in radius.

Decent 26" tyres are more available in small towns. With a 700c or 27" wheel you may find that you have a choice of flimsy, skinny tyres and nothing else. (thanks Batman). In a pinch you can tour on cheap MTB tyres more easily than cheap 700c tyres, because a cheap, skinny tyre is going to puncture more easily and not deal with touring loads as well. I've seen a lot of bike shops in small towns in the first world that have BMX tyres, 26" off-road and city tyres, and 700c "race" tyres, all cheap unbranded tyres. It's not a choice between an expensive good brand and a cheap one, it's a choice between two widths or styles of the cheap one. If you have a choice. Or wait a week or more for mail order, because your order goes by air to a major city, then road to a minor city, then bus freight to where you are. Ideally you'd always carry a spare tyre, but in practice that just means you're waiting to replace the spare rather than the currently wrecked tyre.

Another factor is ease of building a frame that will accept fat tyres with the wheel size. Once you add a 2.5" tyre to your 700c wheel the frame gets quite large (29er MTB frames), which makes designing for low stand-over height harder and all the stresses on the frame get larger because the tubes are longer making for longer levers. The differences are small, but they add up - a slightly longer lever needs a slightly stronger tube, so now you have a longer tube that's also heavier per unit length, and overall the 10% extra length means a 25% heavier tube.

You are also more likely to find disk brakes on expedition bikes, because again they're more robust. Not necessarily the caliper and rotor, but the wheel as a whole. If you get a buckled wheel, with disk brakes the critical question is "does the buckle clear the frame" (ie, does the wheel go round), but with rim brakes it's "can I adjust the brakes to clear the rim" (that ignores "do the brakes still work like that").

The reason you see Rohloff hub gears on expedition bikes is the same. Sure, they add cost, but they are reliable. Not only do you lose the low-hanging, fragile rear derailleur, the straight chain line and high chain-ground clearance means chains last longer. The hubs go 5000km between oil changes and 150,000km or more before needing replacement. As a bonus you get a stronger wheel from wider spaced, symmetrical flanges (that are also taller). Again, it might be 1kg heavier, but when you're loading 50kg or more of stuff on the bike, do you really care?

.

The motivation for a lot of this is that it's all very well saying "I'll just get a lift to the next town", but if you're riding the Birdsville Track in the off season (recommended to avoid getting run over by tourists) you might wait several days for the next car to arrive. And they might not be able to carry your bike as well as you. So not only do you need enough food for 500km, you need water for at least a week (2-3 days between water supplies, plus a reserve). Then you have to get a lift back to your bike with parts, fix it, and ride on. Much better to pay a bit extra and get a bike that doesn't break in the first place...


I think you kinda answered your own question. If the noise appears only when force applied to the right pedal, it's almost certainly that pedal. Especially as you changed the BB already.

Check for play between the pedal and the crank. Turn the pedal and see if you can feel a 'hitch' or click.

Most bikes shops have a pile of old pedals (especially cheap platforms that come with new higher end bikes that get swapped out for clipless pedals). Ask if they will swap out your pedals for a set that are know to work OK as a test. If the click goes away - bingo. I'd ask them for a bit if a deal on replacing the pedals as they mis-diagnosed the problem first time around.


Is it normal to feel like I can't breathe while trying to ride at a challenging pace?

I think you should always check with a doctor if you have concerns about your health. While you probably can get advice on your health from this forum, this is not the best place to seek specific medical advice that is going to be right for you.
With that said provided you have no issues that can stop you from training here is what worked for me and others to improve:

Try to use a heart rate monitor to train and/or cadence sensor
What you want to do is ride for 30-60 minutes at a constant heart rate and a cadence of 75-90 RPM (Note if you are trying to do strength work going as low as 65 RPM is ok, but note it does put more stress on your knees so listen to your body).
What you want to do is use the gears on your bike to allow you to maintain that cadence and maintain a heart rate that essentially stays flat for the duration of the ride. If you ride in spurts, like you pedal hard and then recover, that will not help as quickly to build your aerobic base up. Your aerobic base will let you ride longer without going above your anaerobic threshold.
Interval or training in Zone 4/5 is something that usually is done less often to help increase speed or functional threshold power (FTP). For example, once you build up a base, can ride around for a while, and know the gear that works best for you to do that you can go to the next harder gear in your rear cassette and try to ride for 30-60 min at 65 - 90 RPM. That will make your heart work slightly harder and force your cardiovascular and skeletal muscles to adapt to the harder work load. Your heart rate will probably slowly keep climbing when you do this and you will probably ride at a slower speed until you fully adapt.

The approach above worked well for me to go from being able to ride only 13 MPH to being able to go 17-20+ MPH while staying under my anaerobic threshold within a year or so.
Here is a boring stretch from one of my rides with metrics where I am doing some of the things outlined above.

Pedaling the whole time.
Managing the gear I am in so that I am able to keep pedaling between 75-90 RPM  and my heart rate in Zone 3/4 for me. Yes in a few small inclines I dip below that cadence, but I usually do strength work between 65 and 75 RPM so it is something I have adjusted to. On a separate note, for some of my personal goals some of my rides focus on Zone 2/3 and Zone 5 depending on what I am trying to work on.
Note your target heart rate will probably be different than mine - Heart Rate Calculator.

Doing some rides like this where you are not trying to push max speed or go up super tough climbs I found has helped and often takes some self discipline to do cause let's face it...going fast and/or climbing hills is fun ; ). You can also take this same approach to a mountain bike on a gravel or off-road trail as well.
Also note there is no way I could do this ride at this effort level 3 months into riding. I still remember having to stop in the middle of a 13 mile ride when I picked up my new bike. However, with doing the things outlined above I eventually got there and you can too.

Hope that helps.
Addition:
One this I struggle with in the cold is breathing through my nose and often due to the cold breathe better through my mouth. Also as others have mentioned, in sports to get more oxygen into your body you should breathe through your mouth.


Seatpost won't let me set my saddle "level"

Unfortunately, this is a common issue with more basic seat posts.

There are 2 options:

Use sandpaper or a Dremel to remove the teeth which fix the angles of the seat post. If you make it completely smooth, then you can use grip tape like that designed for a skateboard deck to add friction without locking you in to specific angles. This approach has drawbacks. The grip tape may need to be replaced on occasion. You need to be careful not to remove too much material from the post, as it risks breaking the post in use. As you can imagine, that would be painful.
Replace the seat post with something without that limitation.

I hope that helps.


Feel free to edit this answer to add more resources.

Hand cycling is a Paralympic sport, administered by the UCI. There are links at the bottom of the UCI page for all world regions.

Here is a link for Disabled Sports USA, describing different kinds of bikes and listing local chapters and a bunch of useful links.

The United States Handcycle Federation seems to be mainly about competition.

Cycling Australia has a Para-Cycling page, there is the Queensland Sporting Wheelies and Disabled Association, and Wheelchair Sport NSW. I'm sure there are bodies in each state, but a quick search didn't locate them.

Good luck!


A tube should not have excess length, and doubling on itself will cause the tire to feel uneven while riding, as well as increase the likelihood of flats.

Assuming the tube is the correct size for the tire, as you said it was, there are 2 common causes for this problem.

If you installed the tube without inflating it first, just a tiny amount, then it hasn't got the shape to sit in the tire completely, and it will appear to be too long. It isn't, just add enough air to the tube to give it a little shape and try it again.
If you did that already, then in the process of inflating the tube to make easier to install in the tire, you have probably inflated it too much, and so it has gotten larger. It's not permanent, just let the air out and inflate it only enough to give it shape before installing it in the tire.

If these don't work, there is likely a problem in manufacturing, and you should get the tube exchanged.

Hope that helps.


Can I use microshift bar end shifters with 9-speed deore lx rear derailleur and 10-speed cassette?

So long as it's a 10s shifter with a 10s cassette it should work. Many derailleurs will work so long as they have enough chain capacity and they can fully extend to the highest and lowest gears


What tool do I need to remove this Joytech freehub?

I believe this one is a 12mm allen inserted through the non-drive side. 11mm is out there too.

Usually what I do is clamp an L-type one in a vise, long end up. A long socket would also work but it would need to be very long.


It is always strongly recommended (by the manufacturers, I read it on Shimano's instruction sheet) not to lubricate a new cable when you're installing it. The reason is that both cable and housing are teflon-coated at the factory and lubrication could destroy that. When a cable loses the ability to move freely it is best replaced together with the housing.


There is a lot of material online about the causes of speed wobbles, but I haven't seen spoke tension as a common cause.  It usually something created by, and stopped by, rider position rather than anything on the bike (I know you didn't want to read that).

Just a thought though: wouldn't uneven spoke tension show up in the wheel not being "true"?

In any case, look up Jobst Brandt's book "The bicycle wheel".  It's the definitive text about this subject, written by a very meticulous engineer and cyclist.

http://www.amazon.com/Bicycle-Wheel-3rd-Jobst-Brandt/dp/0960723668
http://sheldonbrown.com/brandt/


Rust on a cassette or even a chain is quite normal in this kind of surroundings is quite inevitable. Also it has little impact other than visual. More frequent wiping and greasing of the chain is one of the few remedies. Buy the cheapest cassettes so that it won't hurt your wallet too much if you have to replace more often than usual.

What is far more insidious would be rust or corrosion on hidden places like the insides of tubes for a steel or aluminium bike. Or the kind of corrosion that will fuse parts such as bolts. So you should take bits apart more frequently and apply a thin coat of grease where metal touches metal. You should also apply spray wax to the insides of the frame.

Keep an eye on seat-post, stem and handlebar. And get stainless and coated brake and shift cables.


What is the necessary equipment on longer bike rides?

Answering as a road cyclist ...

For a ride of this duration (less than a day), before starting I take notice of the conditions, and decide what to wear, in how many layers.

I want to carry a spare layer to put on during stops, and in case of bad weather. Usually it'll be my lightweight wind and (so called) water proof jacket. Sometimes it's just a windproof vest.

I always start every ride carrying two full water bottles. I would expect to refill them somewhere on an all day ride. I have a mini pump clipped to the frame.

I always carry

My bike multitool. It has more tools than I need, but it's amazing how often I come across someone in need. (My brother asked me for a 5mm hex key once and I gave him the multitool. He said he only needed to tighten something, not rebuild the whole bike :-) Mine is 10 years old and is a BBB version of this Park Tool. I should also mention that I wrap the multitool in a plastic bag. It stops it from rattling, and a plastic bag can be placed between my cap and helmet if it gets really wet!
Puncture repair kit. (Note to self, replenish the used patches). Just a plain repair kit from my LBS. It had chalk, glue, patches, and a piece of emery paper. I lost the chalk but replaced everything else multiple times. This Park Tool Kit is similar.
Three plastic tire levers. One always seems to go boing off into the bush. Again, just generic plastic levers from my LBS.
Two spare tubes. On a bad day ...
Mobile phone.
One banana. For a big day, two bananas.
Wallet.

Except for the banana and wallet, the stuff I carry is all wrapped up and in my middle back jersey pocket. The banana and spare top is the left back pocket, the wallet in the right pocket.

If I have the rain jacket on and have to remove it, I'll roll it into a ball and stuff it the back left pocket. If I have to remove another layer, I'll plan a stop to roll the garment up into a small thin roll and put it the back right pocket. Most of my bike gear has full length zips; I can unzip them to get lots of ventilation before needing to take the thing off. Never had to take off more layers than that; some people suggest tying them around your waist, various bike parts ...


Tire size / rear dropout incompatibility?

Yes, it is unsafe. You should find a set of tires that will allow you to seat the wheel properly into the drop out.


Is it good practice to wave following cars through when safe?

Never. I drive a school bus (and ride a bike, of course - but never at the same time) and when bicyclists wave me through, I ignore them. There is no way that they can truly judge the space that I need without running into an oncoming car or them.

Same goes for when I'm in my car. I trust my own judgment. If it means that I am driving behind them for a bit, so be it.

On my bike, I keep enough space between me and the curb and let them make their move. What if I wave them on, they hesitate, and then go after the golden moment has come and gone? Or if they pass a little too close because they are nervous? At worst, I'll stop and let them pass.  As we all know, folks in the cars don't make the best calls but better than me making it for them.


Can I avoid falling in the rain on a corner?

16 km/h is so slow that even the worst tyres should keep you up, unless something like oil spills were involved.

If something is so slippy that you fall without warning at such low speeds there is not much one could do. If you have a hunch this might happen tripodding corners or getting off the bike may help.

The first drizzle after a long dry spell can leave a very slippy mix of wet dirt on the tarmac. It sometimes feels almost like soap. More intense rain washes it off quickly.

Some surfaces (eg metal or road markings) can get slippy when wet. Avoid anything that looks smooth and wet. edit: The smooth tar of the patched cracks visible in your photo are also example for such treacherous surfaces.

If temperatures are closer to zero black ice may form spontaneously. It is nearly impossible to distinguish from wet road and is extremely slippy.


The Park tool will work. A 14mm socket and a ratchet will also work. If the crankarm  has been loose for some time there is a chance the movement has ruined the crankarm by distorting the square hole. I would attempt to tighten the bolt then see if the arm still wiggles on the crank axle. If there is no movement, ride for a few days then recheck the bolt tightness and for wiggle. If everything is good recheck in a week. then after 30 days. If everything is still tight you should be all set. It is a good idea to check the drive side while you are at it. As the bike looks fairly new I would recheck all the hardware, stem and bar clamps, pedals, wheel QR etc.


Nothing happened or changed. It's just your observational bias coupled with different demographics preferring different bike capabilities.

Many children's bikes have relatively relaxed geometry, which makes them stable which has benefits for kids. Bikes built for adults usually aren't as stable, because stability and maneuverability are at odds with each other, and the adult riders want the maneuverability.

Mountain bikers value fast handling over stability, and so do many road cyclists.

However, many triathlons or time trials are events where maneuverability is not important, so many of those frames are much more stable. Touring bikes are also in that group.

I have a bike built up from a nashbar touring frame, that is so stable I can nearly fall asleep while riding. I hop off that bike and hop onto an 80s Bianchi racing bike, and trying to ride no-handed at any speed less than 35 mph (55 km/h) is virtually an instant crash. My surly cross check is in the middle of that range.


Is there a title that refers to the person who selects the athletes who will join the national team?

The correct title in English speaking nations is Selector. The Selectors use their knowledge of the capabilities and nature of the riders to select those that represent their region or nation. Results are important but if look up any selection criteria you will quickly see behaviour standing out as one of if not the key decider on who gets to represent their country of the elite riders. Selectors work in groups and often are made up of head and team coaches and other national federation members.

Selectors also play a role in identifying talent and bring young riders into the high performance programs offered by the national federations.

There are many hoops to jump through before being selected as a representative. Firstly a rider must be eligible this involves:

being a citizen
holding a racing licence
clean drug tests
attend sanctioned events and training as required

Once eligible selection is then based on a number of factors:

results and performances at national and international events
UCI world cup points
performance in selection trials
ability to work well in a team
would the athlete win an Olympic spot and could they go on to win a medal
technique in team races
behaviour and attitude
sport science results
fit in team composition (mainly in track events)

So in short, selection is based on not only results but a wider analysis of the rider. The Selectors still have a large role in ensuring that the national team is the best group of riders rather than the group of best riders.


Can I estimate tyre pressures on a road bike?

No, not really. It is difficult to get an accurate idea of tyre pressure by pressing it.

Especially for thin, high pressure road bike tyres - they should feel pretty hard. Even if they do feel hard, the pressure may be much lower than it should be.

Best option is to get a good pump, with a built in pressure gauge. Many mini pumps will take a lot of effort to get the pressure high enough, a 'track pump' would be a lot easier.

Tyres do lose air over time - especially thin, high pressure tyres - so it is a good idea to check them regularly, and inflate as required.


(Serious): Male genital protection for mountain biking/BMX and for common falls

Genital protection is rarely (if ever) used in cycling because it generally means putting some kind of hard surface in play (or excessive padding).  Either of these can easily lead to some very uncomfortable chaffing problems.  For less "pedalcentric" disciplines this might be acceptable (flatland, downhill, etc).  But, for the rest of the market there just isn't a benefit to loss ratio to justify it.

Many other sports have genital protection equipment that is used regularly.  Like winter cyclists who have to use mountaineering equipment to stay warm, you may have to dip into some other sports equipment cache to accomplish / try what you are suggesting.


Shimano Hydraulic brakes are often sold as a kit, with the hose already connected to the caliper and lever and the system already bled. These kits are listed according to which hand the lever is for (the front brake's lever can be on the right or left according to country and preference) , whether the caliper is intended for the front or rear (the caliper body is usually the same but the fittings can vary) and hose length (to allow for different frame sizes and suspension designs/travel).

The lever clamp is almost always about 22.2mm (7/8th inch).

The caliper mount on the frame or fork will be IS-mount (bolts from the side) or post-mount (bolts parallel with the rotor).  M640 brakes are natively post-mount.

Adapters are available to fit PM calipers to IS mounts. Adapters are also used if a larger rotor is used. The normal rotor sizes for calipers without an adapter, or using a "+0mm" adapter for mismatched mounts, are 160mm at the front, 140mm at the rear.


Depends how well the chain and chainring mesh.  Assuming perfect alignment, exactly half the teeth are engaged.

In the real world, the chain will be somewhat elongated.  So your worst case is one single tooth is taking all the strain.  At this point, wear is accelerated.

You should use "27 teeth" and "1 tooth" as inputs for your needs.

EDIT ChrisH calculates that assuming a 52 tooth chainring and an 11 tooth rear cog, there will be an 11 degree angle between the horizontal and the chain, on either  side.

So 22 degrees over 180 gives 202 degrees of the chainring are touching the chain.    202/360 shows 56.1%of the chainring, which is 29.18 teeth, so 29 teeth in contact with the chain, highest possible value assuming a 400 mm chainstay length.


Just buy something old and used - don't buy a 100quid BSO from Asda