What exactly happened to my rear derailleur? I had installed my front derailleur and was adjusting the high/low when I noticed my rear derailleur was hitting the spokes of my wheel. Suddenly, I saw a screw pop out and then my derailleur popped into a very contorted position and I had to take it off.

The below photo shows the underside of the derailleur ( Sram x-3) to the right of the place where it connects to the frame is the broken plastic where the screw came from.

What happened, and what does this screw do? Exactly how did I break my bike.

The screw that you are missing there is the B Tension screw. This screw rests on your derailleur hanger on your frame and sets the angle of the derailleur body.

Usually, when you put a new derailleur on a bike you use this screw to adjust the distance of the upper pulley (Jockey pulley) on your derailleur up or down from the teeth on your cassette. You want the top pulley to be 5-10mm away from your cassette teeth when then chain is on the largest / easiest gear. This keeps shifting nice and tight, because the derailleur is as close to the cassette as possible, without riding the pulleys on the cassette teeth.

Screwing this in will move the derailleur body and pulleys downwards, away from the cassette, while screwing it out (or completely out in your case) will cause the derailleur body to be pulled up by it's spring into the contorted position you mention.

Read more about it here (scroll halfway down the page)
http://www.parktool.com/blog/repair-help/rear-derailler-adjustments-derailleur

Also, if it wasn't obvious already— you've now learned why you shouldn't spin the rear wheel while you adjust the High Limit screw...


What are the original components to a 1953 Schwinn Paramount? I have a 1953 Schwinn Paramount that I inherited and have been riding as my daily commuter.  I think most everything is original, but am not sure. Where can I find out what the original components should be, and any idea of its value?

The Schwinn Paramount was a special machine, as Sheldon Brown describes. I cannot tell you what components it had, because it seems that they were custom built to order only.

Maybe the people at the Schwinn Paramount Registry can help more.

Looks like it's valuable. Look after it.


How bad is road salt for my bike? I took my mountain bike out yesterday in the snow. Did some hills around town, riding through slush and puddles, and all sort of dirt/mush/ice/snow.

I gave the bike a pretty good wipe-down after the ride, but I have my outside spigots turned off, so I didn't hose it down.

Should I be worried about potential damage to cogs/rings/chain/etc, or any of the other components on the bike? It's a Specialized Epic, aluminum, full suspension.

Thanks

For a one-off ride in the salt like that, you should be fine for now if you lube the chain and wipe it down. Give the bike a good washing whenever the weather warms up enough to turn on the outside spigot.

In my experience of riding through road salt (and grit, which is probably just as bad) on a regular basis, the bike tends to need a new chain every spring, and a new cassette and bearing overhauls about every second year or so.


I keep breaking the tips off my presta tube stems I can't pinpoint what I'm doing wrong while inflating my tubes.  I use presta valves and have a "Joe Blow" Topeak pump.  I put the tube stem at 12 o'clock, I unscrew the tip of the tube stem (but not too hard), press to let out some air, place the pump head on, lock it on, inflate to 120 psi (as recommended on the tire), then reverse all procedures, trying to keep everything straight (not wiggling the pump head too much).

I inflate before every ride but didn't think that was a problem as long as I'm letting some air out before pumping and am not inflating beyond the max. psi.

Still, after a couple weeks (riding about 3 times per week), the part of the tube stem that screws up and down is gone, and a few weeks later, after inflating, all the air rushes out when I take the pump off, then it won't hold air again.

The last time I replaced a tube for this reason, I decided to keep the little nut in place at the base of the stem near the tire (though my mechanic says it's unnecessary) and to keep the dust cap on the stem.  I'm thinking these two items might not be necessary to most folks, but they'll perhaps protect against whatever I'm doing wrong.

Any other advice?

I also use a Joe Blow on my prestas.  After I had a couple valve stems bend and/or break, I started making sure I only unscrew the stem a little bit.  My theory was that by unscrewing the stem all the way up, it was easier to bend or break when pulling the pump head off.  Haven't had it happen again since.


Face gets extremely red when biking in the cold ~5c, and then going indoors, due to temperature change maybe Face gets extremely red when biking in the cold ~5c, and then going indoors, due to temperature change maybe.

What can you wear when biking to prevent this problem, and could you link to a site? Thanks a lot.

You can't really wear anything to solve the problem you are describing.  If your face was cold, I'd recommend you purchase some sort of mask, however, that isn't your stated problem.

When you exercise you generate heat, your body tries to channel that away by dilating blood vessels and sending that heat to the surface (your cheeks) where it can radiate away.  If you are cycling when it is cold, it can reinforce that effect since your body would be sending extra blood to try to heat your cold cheeks.  If you have generated a lot of heat cycling, then go indoors, you may also feel extra warm now that you have a lot of generated heat, are dressed for cold weather and in a warm room.  Again, flushed cheeks.

I regularly bike to work in cold temperatures.  I start wearing a mask at 0F to protect both my lungs and face.  It's a very normal occurrence for me to have red cheeks up to an hour or so after arriving at work.  People sometimes comment, but I know it's normal for me.  I only start to worry if I get white patches (frost nip or no blood flow to areas that were over exposed).


7 to 11 cassette upgrade or new bike I've recently purchased a 1986 Schwinn Passage. Everything works great, but I'd like to upgrade to STI shifters and the Cassette. I've found a great deal on a groupset, Shimano 105 5800 11 Speed. My current cassette has worn down from the previous owner and one of the teeth on the smallest gear is worn down. I've been looking at Sheldon Brown's articles and I'm unable to figure out what I have.

I'd like to know the best way to go about upgrading my current bike, or if it would be better to purchase a new one instead.

A 11 speed cassette would mean a new hub (probably a new wheel realistically) and likely a new derailleur to match the cable pull of the STI shifters plus the labor (this includes installation of the new cable stops, new cables, re-wrapping the bar after putting on the new brifters, etc.). You will also need to spread the frame to get a modern hub in there, which we can count under labor.

If you want to keep the bike: You're better off putting on a new 7 speed cassette or freewheel depending on what you have (I'd guess its actually a hub that takes a freewheel) and either living with the current shifters (downtube shifters are lovely and incredibly reliable when you get used to them), going bar-end shifters, going Retroshift or putting a Shimano derailleur and using the 7 speed Shimano Tourney ST-A070 (there is a double & triple version) or compatible Microshift shifters (SB-R472 for doubles/SB-473 for triples).

If you want to get a new bike: The price of STI shifters and the fact that 7 or 8 speeds is more than enough makes a new bike (or a used bike with STI shifters) a good option unless you're particularly attached to this frame (and everything else is in decent condition or good enough condition that you're willing to bring it to acceptable for you).


Does anyone make a clamping spoke wrench? I'd like to find some sort of "spoke wrench" which actually clamps onto the nipple (not the spoke proper), so that nipples that are slightly rounded-over (or, like aluminum ones, have a propensity to round-over) can be adjusted without further damaging the nipple.

The Park SW-10 is exactly what you are looking for. It can really save the day. If possible, use it (and a healthy dose of light lubricant) the moment that you notice any stripping to completely remove and replace the damaged nipple. I've seen very old versions of identical design, and wouldn't be surprised to learn if it dated back to penny-farthing days.


Choosing hubs and rims for training road wheels I'm going to build a training road wheelset for my touring bike. I wonder what should be criteria for choosing hubs and rims and spokes. I'd prefer cheaper options as long as they are durable and not too heavy.

Hubs: which are considered serviceable as opposed to disposable? And which require relatively little maintenance? My bike has 135mm rear dropouts, so I need MTB rear hub, but for front - search for MTB or road?

Rims: there are many budget models with slight variations in weight and strength. I'd like to find one with maximum strength / weight ratio, but how can I estimate the strength? Say, AlexRims DA22 is advertised as butted but it weights same as 1.5x cheaper Mach1 non-butted rims. Is butted any better if it's not lighter?

Front hubs on mountain bikes and road bikes are all the same width, 100mm (except for some downhill hubs with through-axles). So you could use either type, they would fit in your forks fine.

Note nearly all current mountain bike hubs are designed for disc brakes, so include mounts for attaching a rotor. You can still use them on a bike with rim brakes, just don't fit a rotor. The disc part would increase the weight a bit, so they will be a bit heavier than an equivalent road hub. Also the disc mount means the hub is not symmetrical, so the wheel has to be dished. This makes it a bit more complicated to build, ie it needs different spoke lengths on each side. But this doesn't really matter, you can still build a strong wheel with either sort of hub. And disc mounts would be useful if you wanted to fit disc brakes in the future.

As for which hub, generally mid-range Shimano hubs are good. eg Deore or LX for mountain bike, or Tiagra or 105 for road. Usually they just work fine for years, with hardly any maintenance. Shimano hubs typically use cup-and-cone bearings, so they can be serviced, and the bearings replaced, but this may be a bit fiddly.


Why is there a koozie on this bike's chainstay? A friend of mine recently purchased a used hardtail mountain bike. As he showed it to me, I noticed that there's what looks like a koozie wrapped around the chainstay, towards the rear axle.

The branding on the koozie is the same as the make of the frame (Stevens), and it's being held on by velcro. It doesn't appear on the manufacturer's website as far as I can tell.

The outer layer seems like it's nylon, and there's some minimal padding.

What's the purpose of this thing, and what do you even call it?

I've included a photo for reference.

That is a "chain stay protector" and it is installed in, let us say, a non-traditional way.  Typically it would be a couple inches forward of where it is.

As the name suggests, the purpose of the pad is to protect the chain stay from wear and damage from the chain, which can hit the stay with a lot of force when riding at high speed over rough terrain.


Can't shift to gear one or two I had an issue where every time I put my bike in gear 3, it would just keep "skipping". By this I mean that it wouldn't stay in gear 3; the chain would go onto it, then fall onto gear 4, then go back onto it, then back on 4.

Some Googling showed me that I might need to adjust the rear derailleur. So I set about doing this today by first putting my bike onto the biggest cog and adjusting it so the derailleur was in line with the cog. Then I shifted it down to the smallest one and did the same thing (I think I got a bit confused between this and changing the screws to line these two up with something).

Anyway, as luck would have it, this fixed the problem of the skipping however I now can't shift into gears one or two (the two biggest cogs). Like I literally can't flick down the gear lever to put it into these gears.

What could be the issue? I would love some advice.

Thanks

If you were able to shift into all of the gears prior to your adjustments then it would make sense that you need to readjust.  It sound like you you have adjusted it too far outboard.  I would take it in significantly so that when in 1st gear position on the shifter you are on the largest cog.  From there you can make fine adjustments for shifting between gears.


Does gear ratio affect Power? Let me preface by saying that this may not be the right SE. I considered asking on the Physics SE, but I thought I might try here first. If it is wrong, I am not against it being migrated.

From basic principles of Physics, power is computed as Work/time. So consider a rider and bike system climbing a hill. The work done is the difference in potential from bottom to top, and obviously the time will be climb-time.

Now, my question is:

  Given the same rider, same bike weight, and same climb-time, does your gearing affect power? Also assume that the climb is efficient, no slipping tires, normal pedaling, etc.

From a physical perspective, I expect the answer is no. Same difference in potentials, same time, same power. However, from the rider perspective, I know that it sure feels like a lot more power is being used to climb with a harder ratio.

I expect that the answer is that the disparity comes from idealizing the system. If we consider the bike a closed system, we expect that all the energy put into the bike carries it up the hill, but this is not the case. Moreover I think the inefficiency of the human body will be relevant. However, I still cannot resolve the question.

I suspect you mean efficiency rather than power.

In my opinion the main trade-off is between increased biomechanical losses at higher rpm (basically muscle friction) and decreased blood flow with higher forces at lower rpm. The balance depends both on the rider and the duration.

In the IHPVA Journal of Human Power, Issue 45(pdf, index here) is a paper called Maximum Human Power where they talk about Tyler Hamilton winning the Mt Washinton climb in 51 minutes:

  "he rode much of the climb, however, in the 23-tooth cog, and made several surges in the 21." If he had 700- mm wheels, as seems likely, his average cadence would have been 63 RPM.

The whole article is worth reading, and it might pay to browse the index for similar papers.

The flip side is that top sprinters often go well over 150rpm in the final sprint. At that point they're trading biomechanical efficiency for peak power. I used to peak at over 900W for 10 seconds (>8W/kg) at around 130rpm, but my hour performance of around 350W used a cadence of about 80-90rpm.

The real answer is specific to you. It will depend on your body shape, muscle type, fitness and more transient factors. It's also a question best answered by experiment, and should be part of your tr4aining schedule if you're competing. If not, I suggest finding a climb you ride regularly and keep a training diary.

There has also been much discussion over the hydration for long climbs. Is it better to hydrate and start heavier, or run slightly dehydrated so you weigh less? IIRC the conclusion was that hydration was better, but I can't find the reference.


Aluminum fork: paint defect or sign of strained? I know there's a lot of question regarding paint defect or crack.
But I need your opinion about this.
Recently, I bought new bike but discounted and it's the last piece of it.
On the back of the aluminum fork has this appearance:

I thought it's really about paint defect or it isn't?
What's the possibility if somehow deformed?
I didn't see or feel any problem when attaching the front wheel and when riding it.
Means that there's no apparent bent or misalignment between left/right fork.
I'm really curious. Thanks!!!

I think that's a paint defect.
Aluminum would not stretch enough to flake the paint off like that without staying deformed or actually cracking.
If the fork or wheel had suffered a collision into a solid object that had bent the fork, you'd see evidence in the paint on both the front and back edges.


Do aluminum rims provide better braking than steel ones when wet? When I upgraded the brakes on my bicycle recently, the shop asked if I wanted to also switch from my (chromed) steel rims to aluminum rims, saying the aluminum rims would provide better braking power.  I opted not to at the time to save money; with the brake upgrade (old-style sidepull caliper to dual-pivot), I have plenty of stopping power when dry.

In the rain, however, my brakes are almost worthless.  Do aluminum rims provide significantly better braking when wet?

Since you have gone for steel rims and need to stop in the wet and are unlikely to upgrade to alloy rims straight away, I think you are deserved of a practical answer...

In the wet, with regular brake blocks, the alloy rim will have a better coefficient of friction than the steel rim. This much is known and these brake blocks are the wrong ones for your steel rims. You need the brake blocks designed for the job, the ones with a leather face:

Typically these are nice and cheap, they also last a very long time. In the wet they work remarkably well on steel rims, although it can take a wheel revolution for the braking power to kick in. To work around this 'turbo lag for braking' you can put the brakes on extra early to clean the rims of water and get into a habit of having your brakes ready on tricky descents, junctions etc.

You can run them just on the rear wheel first, in that way you can see how they work and use your existing rear pads on the front when the existing set run out.

Don't let their hum-drum appearance put you off - if you have steel rims they are a performance product.

If you want the in depth on 'coefficient of friction' as it applies to bike wheels and different materials, here you go:

http://books.google.co.uk/books?id=0JJo6DlF9iMC&lpg=PP1&pg=PA248#v=onepage&q&f=false


Why are there metal shavings in my brake pads? I have several brake pads on my cantilever brakes that have several small metal shavings embedded in the pad.  Is this normal?  What should I do about it?

This is normal to some extent - brake pads have to be made of soft material which wears down on the rims (and conversely, the rims wear down into the brake pads to some extent) in order to stop you. This means the pads pick up grime and bits of metal from the rims and road and stuff which embed into the pads and in turn wear down your rims / reduce braking efficiency. If they're eating large portions of metal, then you should probably switch the pads to ones made of different material (anecdotal evidence suggests the pads which come with most cheaper brakes belong in the trash).

I'd start with a high quality pad (e.g. Koolstop Salmon pads), and making sure the rims are clean (use citrus degreaser/rubbing alcohol). Mavic and some others make special blocks for cleaning and (slightly) sanding your rims as well, which you can use (but definitely not necessary).

If you do get metal or other contaminants in your pads though, you can pick it out with tweezers and buff the pads with some fine sandpaper (remove the grit afterwards!). Make sure the pads have sufficient material leftover after this - if the metal backing comes through, your rims are going to take damage.

Also, make sure your brakes are properly adjusted: http://sheldonbrown.com/canti-trad.html
http://www.parktool.com/blog/repair-help/cantilever-brake-service is a good link to look at as well (Specifically see the "Pad Wear" section). If your brakes are rubbing on the brake tracks, you'll pick up more cruft (and wear out your rims), for example.

Also, check your rim wear indicators (if you have them - they're reasonably common on modern rims) to make sure that you're not too worn on the rims as well (this is typically a little groove which should be there on the rims, but can appear in other forms such as something that appears when the rim is too worn out). If you don't have them, you can try a procedure like http://archive.ctc.org.uk/resources/Magazine/20011163.pdf. If the rims get too worn, they break and you end up hurt (probably).


Spoke and nipple compatibility My spokes are described as follows:

  American Classic round spoke (butted 14/15 gauge; 2.0/1.8mm), black 286mm (without nipple).

Does this imply that the correct nipple to go with them would be 15 gauge? I assume that the thicker gauge is at the outer ends, if I've understood butting correctly.

With wire (and spokes) a larger number for gauge is a smaller diameter.

This is why the metric conversion seems the other way around.

14 / 2mm is the larger diameter here, and yes, it's at the ends, or rather, the hub end.

Straight spokes are straight, single butted are thicker at the hub end, double are thicker at both ends, and triple butted are thickest at the hub end, narrow in the middle and slightly thicker at the nipple end. Says Sheldon.


Livestream 16 hour bike race So next week a friend and I are going to be a support vehicle for a 500 km bike race. We wanted to setup something so we could live stream the whole event and wanted to ask if anyone has any experience with the best way of doing this. We will have around 4 or 5 stops evenly spread out on the track. One of our biggest challenges will probably be the battery.

The gear we have or is planning on getting

2 x GoPro 3 with extra battery
iPhone 5 with a 50 GB data card. (Is that enough?)
3 x 6000 mAH power packs to charge phone and GoPro

Our plan is to attach the phone and GoPro to one of the bikes and swap the power backs on each stop. Will this work? What other things should we consider?

We are planning on using https://livestream.com/
We will have a laptop in the car as well.

Will update this post with what we find out.

To avoid changing batteries, you could opt to get an external USB battery pack and power it off of that.  That way you could get a continuous stream. If you got a big enough battery pack, you would most likely be able to power the iPhone and GoPro off of a single battery pack provided you found one that was big enough.


How do I know what is wrong with my brakes? My brakes are not powerful anymore, it takes a few meters when fully pulling my brakes for my bike to come to a stop. Which means that the brakes'pads are touching the wheels but not enough.

So, my question is: how do I know if I need to change the brake pads or give more tension to the cable?

How thick are the pads? Are these rim brakes or disk brakes? For rim brakes, the block (rubber) will get worn away over time so you should adjust the cable occasionally, but well before the block is so thin that the shoe (the metal backing) starts to scrape on the rim.

For disk brakes it's essentially the same but the pad is thinner and made of harder material. The manufacturers usually give a number how thin the pad can become, something like 0.7 mm.


How does one wipe clean and oil the chain? (maintenance details) This may sound like a dumb question -- I know how to oil a bike chain, but apparently not how to do it correctly.
I have a relatively new gravel bike, a Giant Revolt, which I ride (on tarmac) about 25 km a day and whose chain I've been oiling regularly, about every 2-3 days, just as I'd done with my previous bike, a mountain bike.  I took my gravel bike in for maintenance and they said I was overdoing the oil, that in fact it was better too dry than too wet.  What they said I should do is -- after every ride -- clean the chain with a towel and then oil it "lightly".  What's "lightly"?  "One drop" they said.  For the entire chain?  I doubt it -- but I'm not sure what they meant exactly.  (I should have asked when I was there, but now, given Covid, it's very hard to get in touch with them again -- we have to make scheduled appointments to see them).
I'm looking for 'easy daily' maintenance -- not 'thorough' chain cleaning, as I've read about in other posts.  Just enough to keep things clean and well-oiled, that is, getting the chain clean with a towel and then lubricating it again.  I guess the crucial question is "how much oil?"
Again, in some ways this is a very simple question, but the devil lies in the details, and that's what I'm not clear about.

Wipe the chain down with a rag to remove dirt and old lube.
Apply lube while spinning the chain. I tend to use quite a bit (a small drop on every second chain link or so). It’s cheap and the next step takes care of any excess.
Wipe down with a rag before the next ride.

In dry weather it can be sufficient to do step 1 only and skip applying new lube for a couple hundred kilometers. It can also be a good idea to use “dry” or “wet” lube depending on the season.
Edit to answer the comment: “Dry” lube is less sticky and good for dry environments where sand and dust sticking to the chain is your main concern. “Wet” lube is stickier and more viscous, best for wet weather because it’s not so easily flushed out of the chain.


What inner tube size I have a early 1960’s Schwinn Corvette with a tire size of 26 x 1 3/4 S7. I can find the tire replacement but not the inner tube replacement. Can anyone help me ?

Proper S7 571 tubes for this have existed, but you're fine using 559, ie anything that says "26 x 1.75" or covers it in a range.


Linseed oil application to the inside of a steel frame Is the application of linseed oil to the inside of a steel frame still recognized as a good way to prevent the formation of rust on the inside of the 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.


Road Bike Wheel Replacement Simple question for a new cyclist. I want to change my wheelset to these (http://www.rolwheels.com/wheels/wheel/volant-r-t).

Will they be compliant with my current bike? (https://www.norco.com/bike-archives/2015/valence-a3/).

Thanks,

edit: Also, what parameters and specs can I use to determine this on my own?

Answer Looks like a straight swap (but the proof is always in the doing.)

Neither link say what size the wheels are, so assuming the most common 700c size for both and the wheels will fit under the brake bridge.

Neither link says anything about spacing, but we can expect the front is 100mm over-locknut because that's standard, and the rear will also be 130mm (check this) which is the standard for 9-11 speed.

The cassette should swap over okay, yours is 9 speed and the new wheel is 9/10/11 speed.

Rim brakes will need some adjustment, but both rims are alloy so the brake pads shouldn't need to change type.  You may choose to replace brake pads anyway so there's a fresh surface to work with.

Observations:

The new wheels say "Recommended rider weight limit is 109kg (240lb)" so that should be noted.

You're going from a 28 spoke front to a 24 spoke front wheel.

Have you considered investigating why your current wheels are loosing spokes?  Could be a badly machine-assembled wheel, or budget spokes.  A bike that has been left out in the weather for years can suffer, but that's probably not the cause here.

Are your spokes all breaking on the rear or the front or a mixture ?

Freedom isn't exactly a high quality brand, so rebuilding the old wheel on new spokes may not be worth doing, unless you will try it yourself.

I see there's a 32 hole version of the wheel as well.  Could be your norco bike is rated for a lighter rider ?


Can anyone help me identify this bike from 2002? I got it as a gift in 2002, I was a kid back then. And it was stolen from me in 2004 and I didn't do anything. I would love to buy the same model now, but I can't remember what it was and unfortunately I only have one blurry photo. I just hope I can find an expert to identify this bike. Thank you very much in advance!
By the way, it had a blue seat with a bird sewed, but I can't remember that very well either, must it been an eagle.

This bike looks like my 1998 Specialized Stumpjumper based on color, setup and my guess that the logo behind your left leg is a Specialized S. That's the best I can given the blurry photo and the mud on the frame.


How to build a wheel I'm in the planning stage of building a new bike. This will be a light road bike for city runs and transport. For racing I have other bikes.
I'd like to build the bike from ground up by assembling everything myself. Not sure wether to go for gears or single speed yet, but that isn't relevant to this question:
What parameters would I need to consider when building a set of wheels?
I will probably go for steel rims to get a classic look. I've already found out how to calculate spoke length, and I'll try to find an old fork to mount the wheel on while building it.
The wheel consists of four parts:

Rim
Spokes
Spoke nipples
Hub

Protips on good parts? I guess specially the hub is important. Are there any real difference to cheap and expensive spokes as long as they are not carbon fibre?

What spoke arrangement should I go for; cross-laced or straight. Pros and cons?
In what order do I assemble the wheel?
What is the best spoke tension (given I can measure the torque)?
What tools do I need?

Any general good advice when building a wheel is appreciated as I'm totally unexperienced doing this.
A lot of questions that is. If anything is unclear, just ask and I'll elaborate on it. Thanks in advance.

The best suggestion I can make is to read "The Art of Wheelbuilding, by Gerd Schraner".

As for materials:

Use aluminum, double walled rims. They are stronger, lighter, and believe it or not easier for a new wheel builder to get true and round than steel rims will be.
In addition, steel rims for a road bike will be difficult to come by in new condition.

Spokes:

There are major differences in the strength and pliability in steel spokes. Even if you ignore spokes from other materials, which you should, look at double butted (usually 2/1.8/2mm) steel spokes from DT Swiss, or if you want really high quality, use the ones from Sapim. Read the Art of Wheelbuilding for more detail on why.

Use a high quality hub, something with a forged hub shell, and good quality bearings. Shimano Ultegra or Dura Ace, if you want good, loose ball bearings. Hope, Phil Wood, or any number of others for good quality sealed bearings.

Use brass spokes nipples.

You will need the following tools:

A good quality truing stand
A set of good spoke wrenches
A nipple driver (broken link, see Park nipple driver instead)
A quality tensiometer
Spoke Freeze or similar (broken link, see Pro line Accessories or at wheelbuilder.com).
Method of determining spoke length
The components listed above
Time and practice.

I hope that helps.


Brakes loose, cable hanging out I used my brakes the other day and this happened (see photo). Is there any way to fix this?

I’m unable to use the brakes at all with this issue.

The inner cable is very rusty. I would think that the cable friction is so great that the spring of the brake cannot pull back against it. Maybe at the other end of the cable, something has popped out of place, you can inspect the other end and see if this is the case.
Ultimately, the solution is going to be to fit, or to have fitted, new cables and the brakes setting up again to work well. If that cable condition is indicative of the rest of the bike, a good service is due which will make it nicer and safer to ride.


Helmet strap loosens as I ride then the day after becomes too tight Well, the title sums it up. It's a cheap (~50 EUR) KTM helmet. This is reproducible, is happens on every ride: if I adjust it to fit well at the beginning of the ride, it's loose after a while. If I tighten it during the ride then it is way too tight at the start of the next ride.

Two One hypotheses:

The straps are getting wet with sweat and loosening, then constricting again when they dry. Nylon does in fact absorb water and stretch when it gets wet, so this is the more likely cause.

2. Exertion causes vasodilation. If you've had the sensation of your necktie getting tighter under stress, this is the cause. Your body is pumping more blood to your head and the veins are expanding.


Does the saddle height need to be changed when the crank length changes? On my road bike I have 172.5mm crank and my saddle height is 810mm from the bottom bracket. On my track bike I have a crank arm 165mm. Do I need to change the saddle height on my track bike? Will it make any good difference on my pedalling efficiency?

Saddle height for new bike setup purposes should always be set relative to the pedal, not the BB center or any other reference point. So yes, crank length makes a difference.

Using the ground or BB center as a reference point is convenient for re-establishing a given height after the post has been moved, but not for setting up one bike to have the same leg extension as another.


Non Removable Presta Extension Just got a pair of tubular Vittoria Rally road tyres. They look perfect but the problem is that the valve is 42mm which is no good for my new awesome 50mm rims. Above all the valve core is not removable so the extenders I've got with them are useless.

The question is if there's any mean to extend the valves up to 60-80mm in this situation or should I return it back to the shop?

Thank you in advance for your advised.

There are multiple types of valve extension:

The extenders you have relocate the valve core.

The other kind are a plain tube which tapers with a similar profile to a normal valve, and screws onto the valve, over the existing valve core. Once the tyre is inflated you can remove the extension and tighten the valve-lock-nut.


Where to buy 2012 SE Lager parts? Two years ago, I got hit by a car. I was fine, but my bike's fork and front tire were destroyed, so I got a new bike. Now this bike has been sitting outside for 2 years. If I wanted to replace everything but the frame, what would I search, and where would I get the parts? Assume I know nothing about bikes, but I'm very handy with tools. I also have access to a machine shop and any "normal" tools, but the only bicycle-specific tool I have is a chain tool and tire levers. I imagine it's probably not worth it (financially), but I think it's worth it to learn more about bikes and bicycle repair. Also, I welcome any other tips, suggestions, or advice.

Note: I brought the bike to a shop. They were skeptical I'd be able to salvage the frame, but they inspected it and concluded it wasn't damaged.

Edit: I'm in Boston, MA, USA

Most bicycle parts are fairly standard, and your bike doesn't look like an exception. There are several mail order stores and local shops that sell bike parts, just pick one. This site is fairly fanatical about not making recommendations, but just knowing your location could help.

Good places to start reading about bike maintenance and repair are http://sheldonbrown.com and http://www.parktool.com/blog/repair-help/.


Is a garmin oregon series GPS useful as a bike computer for navigation and ride tracking? I'm considering purchasing a standalone GPS unit. I've heard good things about the Garmin Oregon series devices for touring since they can be used with commodity batteries.

Is a Garmin Oregon series GPS useful as a bike computer for navigation and ride tracking?

I might want to use it to track rides to upload trails to MtbProject.com or Upload rides to Strava?  I may also want to use this for basic navigation from pre-planned rides downloaded from ridewithgps.com.  I also see myself using the maps for offroad MTB exploring in the national forest near my house.

Navigation, Tracking, and Map availability are more important to me than training features. I'm not fast, I don't care about heart rate / cadence, I just want to know where the hell I'm going and being able to figure out where I went after the fact.

Are these things that will work well with the Oregon series GPS units?

Yes, you should be able to use a Garmin Oregon that way. A Garmin Oregon can do almost anything that a Garmin Edge (GPS bike computer) can do. The exact details will depend a lot on exactly which Oregon and Edge models you're comparing.

Most of the current Oregon models actually can connect to a heartrate or cadence sensor via ANT or Bluetooth.

They can definitely log a track and show you a route.

The biggest downsides to using a Garmin Oregon on your bike are:

You'll have to buy a bike mount separately. That's maybe $10 extra.
There aren't quite as many mounting options. Garmin Edges have a (purchased separately) mount option that sticks out in front of the handlebars, with an Oregon your only options will probably be handlebar or stem.
The Oregon is physically larger and heavier. (but not a ton)
It's likely that the controls will be a tad harder to use without looking down, since an Edge is purpose-made for bicycling. This is likely to be very minor, though, and I'm sure the Oregon will be fine.
No power meter or speed sensor options. For your described use, I'm sure those don't matter, though. A speed sensor connected to a GPS will be more accurate than just a GPS, since the GPS isn't perfectly accurate and will tend to cut corners a bit.
You'll probably want to load a different map onto it. Oregons usually come with a topo trail map that's perfect for hiking, but if you'll be riding on roads you'll probably want a road map of some sort instead.

The biggest advantages to using a Garmin Oregon on your bike:
 - It's cheaper (than Edge models with maps). Well, maybe cheaper. MSRP range right now for Oregons is $400-$550 and map-capable Edges go from $250-$600 (but I think the $600 Edge only has mapping capabilities as good as the cheapest Oregon). Looks like there's now some "Edge Touring" models for $250-$300 that might do exactly what you want, though...
 - It's more capable than any of the Edges.
 - The screen is bigger and the maps are prettier.
 - If you hunt around on Geocaching forums and such things, you might be able to buy a used older model Oregon for much cheaper.
 - The highest end Edge models have some cool cell-phone integration stuff, like alerting about incoming calls, uploading your track as you're riding, etc...

As for the battery: I carry a separate little rechargeable battery pack that I can use to power my GPS or phone if one runs out of power. You have to do a lot of riding in a day to run out the battery in a day. Personally I prefer rechargeables over alkalines, and the Li-Ions like what's in an Edge are the best battery life to weight+size ratio available. Looks like some of the Oregons actually have an option for a rechargeable battery and AAs to get the best of both worlds...

Here's a reasonable review comparing a specific Oregon to a specific Edge: http://forums.mtbr.com/gps-hrm-bike-computer/garmin-oregon-450-vs-edge-800-a-650537.html -- few years old, but the basic ideas are still the same.

Side Note: I use the lowest end Garmin Edge (200), and find the route stuff in it sufficient for pulling a route out of ridewithgps and following it. It doesn't support a map (like the Edge 800+ or any of the Oregons), but I can load the track in, pick to follow that route, and set the display to show the track (well, just the next 100 meters or so). That way if there's an upcoming possible turn I can glance down and see if it's the turn I should take, and I'll get an alert if I go off the route. There's no maps, so it doesn't know the difference between the road veering right and needing to turn right onto a different road, and therefore it can't alert about upcoming turns. With an Edge 800 or Oregon that's loaded with decent maps of where you'll be riding, you could download just waypoints instead of a full track, and you'd be able to get turn alerts and a map that shows your track on the roads. Still, for only $130 instead of $400+ it's worth considering...


Shifter isn't working, cable doesn't react When I pull the shifter for my front dérailleur the cable doesn't react. Even with tension on the cable.

Now I made the cable loose. Also my barrel adjuster is disconnected, maybe the problem is related to that.

If the housing is loose and falling out of the barrel adjuster, either the end of the cable as come loose, or the housing has come out of a frame stop (or the shifter itself, seeing as you have the bar tape off), or the cable has broken (or cable end in the shifter may have detached). There is also a chance that the shifter is broken.

If you've grabbed the cable (not the housing) and worked the shifter to check the cable is being pulled by the shifter, and it's not, the cable probably is broken or the end detached. Try pulling the cable and see if it comes loose.

You can also check the cable has not come out of the derailleur pinch bolt (or pulled through it). Also, follow the cable path from the shifter to the derailleur and make sure the housing is properly located in all stops.


How does this hand pump work Some time ago I bought this pump. It should be usable for all valves, but I'm not sure how that is supposed to work and it didn't come with a manual.

On one side there's a lever, on the other side (where the air comes out) there are some parts that may have to be assembled in a specific way for different types of valve.

An overview

Lever folded out

Disassembled

Can anyone tell me how this works?

From the disassembled photo, it looks like if you put the parts back together the pump will work for Dunlop valves and Presta/Sclaverand valves (roughly any narrow type valve). You should be able to put the rubber and the red thing the other way around in. Such that the narrow pointy thing of the red part points outwards and the rubber has a wider opening to the outside. That way it should fit car valves.

For the usage, it should work like any other pump with a lever.

(for Presta/Sclaverand valves, screw out the round thing on the top of the valve, to unlock the valve)
With the lever like in the first picture push the pump on the valve.
Then fold out the lever like on the middle picture. This compresses the rubber such that it squeezes around the valve and makes the connection pump-valve air tight. (With Dunlop, this step sometimes failed for me with Dunlop valves as their top part is a bit on the short side, so compressing the rubber pushes the valve out of the pump. If that happens, try again and push pump and valve together when flipping the lever. Once the lever is flipped, the rubber should keep the valve in place)
Pump air
fold the lever in again
pull the pump off the valve
(screw in the "lock" of the Presta/Sclaverand valve if applicable)


Social bike race costume - Morph Suits I've had a blast at a social mountain bike race/relay the other week.  Our corporate team wants to do it again next year, and in costume too.

Question is:  Do you think these all-over costumes would work acceptably on an off-road bike race?  I'm mostly concerned about visibility (the rider seeing out) and slightly worried about sweat and bunching.

Further details: Lap times were 30-35 minutes, so its not a sprint relay.  The track was a mostly flat and dry singletrack with some shingle 4wd track.  Downtime between laps was while 2x 3x 4x laptime, while other people did their lap.

http://www.morphsuits.co.nz/morphsuits/original-morphsuit

http://www.trademe.co.nz/971555375

http://www.trademe.co.nz/968518586

I would look for other alternatives.

These suits are very "one general size" type. Meaning they don't fit very well and have quite a bit of chafing as a possibility. I wore one for a fun 10K a few years back and I am glad I wore my trainer undies with them. I got chaffing around the armpits and the visibility was such that I wouldn't want to be on a single track course. If you must pick a theme to do this event, skip the morph suits.

IMHO
Mountain bike racing and the general silliness of a themed event poses several safety challenges. Usually people are less inclined to take their surroundings into account when their having fun. Add that with trail conditions and people on mountain bikes and I think you'd be asking for collisions and crashes.


Why do current, entry-level shimano rear derailers have large-diameter pulleys? I have seen (and recently bought) entry-level rear derailers from Shimano (Tourney for MTB, 2300 for road bike), and I keep wondering why they are making these parts with such large pulleys.

I don't think this make the parts cheaper to produce, since large size means more material, and I can't see why customers would find this more attractive or adequate than the smaller-sized ones (unless customers would prefer more expensive models because they DON'T HAVE large pulleys...).

Also, I imagine there might be advantages to larger pulleys (less chain link rotation, less wear, slower pulley rotation), but the reason why entry-levels are big, while more expensive models continue to be the same old size, is very unclear to me, not to say arbitrary.

There are 2 versions of derailleurs which come with extra large pulleys.

The first, which is what is being discussed here, are the low end mega-range compatible derailleurs.  A mega-range freewheel has one distinct characteristic which requires compatible derailleurs to have very large cogs.

As seen in the image below, there is a large tooth count difference between the second to largest cog and the largest cog.

This large difference in size requires a large derailleur pulley, to make sure that the chain has cleared the teeth on the last cog, in order to shift into this gear.

If you use a smaller pulley on the derailleur, you may be able to get it to shift, but it will be clunky and loud at best.  At worst, it will trap the chain against the side of the largest cog, and refuse to shift into that gear at all.

The second type of large pulley derailleur is decidedly not low end.

The Berner Carbon Fiber derailleur upgrades are designed to reduce resistance on the drive-train by decreasing the severe chain bends associated with smaller cogs. While expensive, my experience has been an average 10 watt reduction in energy used by the cyclist, with no apparent loss of efficiency in shifting, or in anything else other than the cyclist's wallet.


Rear derailleur shifting poorly, skipping gears I've got a Shimano Sora on a 8-gear cassette, and have odd behavior and skipping, shifting under stress.

This started with a trip to the mechanic for a tune up which replaced the chain. I had some skips so I replaced the cassette. Still more skipping, a second trip to the mechanic didn't do much good.

I tried adjusting it myself and found some odd behavior:

Had to adjust the H screw way out, and it doesn't seem to reliably return to the same spot while pedaling (while working on it).
When I start at the smallest gear and shift to the largest, everything looks perfectly aligned.
When I start at the largest gear and shift to the smallest, the first click does almost nothing. The second goes to the 7th gear, third click to the 6th... and the seventh click skips from the 3rd gear to the first.
After all this, it doesn't seem to move back into the original position without a little push.

Any ideas on what's going wrong here? It seems like tension pulling the chain out is not sufficient, but I don't see any adjustment for that.

Am I barking up the wrong tree?

A tune-up fundamental SHOULD be the proper alignment of the rear derailleur hanger. If the shop doesn't use a Park Tool DAG-1 [derailleur hanger alignment gauge], or some other manufacturer's, to inspect, verify, and correct the relation of the hanger to 3 different points on rim of rear wheel at 180 and 45 degrees apart it is throwing parts at a bike. As the hanger should hold the rear derailleur in direct line with each cassette chain ring, any deviation -- inward or away from the cassette -- induces erratic shifting and skipping that mimics cassette and chain wear.  (Misalignment is difficult to "see" without this tool but may be suspected if the bike has been bumped in a rack, dropped, or fallen, on the drive side.)  The tool at $65 to $75 will be used for diagnosis by a careful shop but is unlikely to be worthwhile for an occasional home wrench.


Can I fit 26 x 2.2 tyres to my 26 x 2.25 wheels on my mountain bike? (Not sure of year)

Specialized Rockhopper
Currently has 26x2.25 tyres, desperately need replacing though,

Mostly used on roads or grass, but trails occasionally

I'm not a professional, I just like riding my bike

If you want to put 2.2" tires in place of current 2.25" tires, then yes, you can do that.

That's less than a 2mm difference, given that tires conform to marketed width at all (which they tend not to). Generally, any smaller tire size (of compatible beat seat diameter) won't cause any issues, unless there's a huge mismatch between rim and tire width (i.e. 40mm internal width rims and 25mm wide tires aren't a good idea, same goes for 10cm fat tires and 18mm rims, but that's not your case).

I advise to consult this page on a topic of tires sizing.


'93 Trek 820 Antelope - Replace? OK, I'm sort of just looking for justification here. I am the original owner of a '93 Trek 820 Antelope, and I am just recently getting back into biking for health benefits. Of course after riding "this old bike" for a couple months, I have the itch for "something new!"

The problem is, knowing my desire for fancy things, even a moderate new bike is going to set me back $2K, and obviously the sky's the limit. I've looked at Trek 520, a couple Surley (Troll, LHT, Bridge Club) and while they are absolutely beautiful bikes, I simply haven't yet convinced myself they are a worthwhile upgrade over my 30lb 25 year old rock solid bike. The 820 has been stored indoors 99% of the time, and only needs minimal service (new chain, new shifters & cables, new tires). So for 1/10 the cost of a new bike, I should be good to go.

Conversely, a new bike has the advantage of modern design (wheel size, frame geometry, etc) as well as A LOT lighter, and just plain cool.

So at this point, since I haven't found any super compelling reason to go with the new bike, I am really thinking of just putting a couple hundred into maintenance and be on my merry way.

My primary riding type is country roads. Mixture of tarmac and gravel. I'm too old and too overweight and too out of shape to do anything close to "mountainbiking"

You don't have to spend $2K on a bike that will be faster, lighter, easier to ride and generally better than your 25 year old bike. (I'm assuming the US here as you used mentioned dollars).

That said, if the old bike only needs minimal maintenance that will not be expensive to do so, get it into a satisfactory condition and ride it for a few months. If you stick with it, then consider a new bike.

If you are not riding proper mountain bike trails, a hybrid bike with no suspension will be perfectly adequate.


Tips for improving commute efficiency/comfort? I'm not "a cyclist", but I've been riding to work for 15 minutes or so each way almost every day for the last three years. I've recently moved and am now 30 minutes away and I find that length of ride to be a qualitative change.

I have a Van Moof 5.1 retrofitted with an SRAM Automatix and although it's heavy, it's very practical and I'm not interested in getting a lighter bike or going for clipless pedals. But are there any other tips for increasing my efficiency and comfort on my daily commute?

I've had to start wearing cycling shorts (because... ouch!) but is there any other equipment, technique or training that might be a quick win?

I have found that if you don't want to invest in equipment the best way to improve efficiency is by ensuring you are fitted properly to the bike you have.

For example: Many non-cyclists do not have the optimal seat height set, or their reach to the handlebars is too great or too compact. If you don't want to invest in equipment, invest in knowledge and ensure you're setup correctly.

Your legs should be between 96-98% fully extended when the crank arm is at its lowest position.  Your knee should be level with the pedal spindle when the crank arm is horizontal.  Sometimes shortening your reach allows you to bend your elbows, arch your back and breathe more easily; sometimes things are too compact and extending your reach improves efficiency.

Even if you think you have things dialed in, if you are feeling flat, I often practice a tip from the Greg Lemond Book of Cycling and move my seat around (up or down, forwards or backwards) about a millimetre or two at a time until it feels better.


Windows Phone as a Bike Computer - What is the current State of the Art? I have a Windows Lumia 532 phone.

I currently use the Cycle Tracks GPS app to track and record trips and then upload to Ride With GPS and/or Strava. There is not a native Strava app.

I've recently upgraded to Windows 10 making available the Gramin Connect Mobile app which will upload to the Connect powered by Garmin ecosystem. I've not yet fully investigated its capabilities/limitations. I've looked at buying the Garmin Edge 25 to act as a standalone bike computer, link to Garmin Connect Mobile and then upload to Connect powered by Garmin.

Apart from this, How else can I collect Cadence and Heart Rate data? Specifically,

Are there other dedicated bike computers which interface with Windows Phone apps like Garmin Connect Mobile?
Which apps allow direct communication with which Cadence and Heart Rate sensors via bluetooth?
Can I get a ANT+ adapter to communicate with sensors via ANT+?

More generally, What are my best options regarding using my Windows Phone as a Bike Computer?
Considerations are:

Capabilities
Limitations
Costs
"Open-ness" ie Are you "locked-in" to one manufacturer?

Having considered between unsing my android phone as a bike computer and buying dedicated computer, I noticed some points that could serve you.

Using cell phone:

You need a bike mount to be able to look at the data while you ride,
moreso for navigation, and they are somehow bulky, just like a cell phone compared to the dedicated bike gps you mention.

Cell phone battery will drain quicker, specially with sensors attached.
Usually, phone GPS is usually not as good, and for instance, I don't think I can connect to GLONASS satellites from my phone (Russian satellites for extra gps accuracy).
Bluetooth only allows for one sensor connected, so if you want to link a heart rate band, you could not link a cadence sensor.
If you want to connect sensors via Ant+ your phone need to be able to receive the signal, which is not the common thing, or buy an ant+ receiver

Usually phone apps give their best stuff on payed premium plans.
Phone apps usually take a good while deciding you stopped, which means a big time increase when measuring city commutes with all red lights etc. This can be avoided with speed sensor

Using dedicated bike computer

There are less expensive units that can connect to a phone to use it as their gps sensor, while the unit serves as smaller cockpit display with ability to plug in more sensors (basically HR, cadence and (more accurate) speedometer), but they won't show navigation maps.
Deciding between bike computers is already very complicated. The main difference is if you need navigating maps your options are less, and the better you need your navigation (i e you plan on using the gps unit on touring bike expeditions) the more clear it is that you need a big screen unit with plenty of battery time and good maps.
If you really like strava you may consider some devices that show strava segments live, but keep in mind this needs strava premium membership.
I found out something about gps recording: some units will record more data points of your traject than other. This could affect shorter strava segment times :P, but looks like it's not a big deal otherwise.
Some units have barometric meters on them, offering  more accurate elevation gain
Some units can display a great amount of data on the same screen
Some units have several training features that could be useful

I don't like and it seems it's not welcomed to give product recommendation, but since you mentioned it, I bought the gps unit you looked at. Still haven't used its follow track feature, but I bought it because of that. If you are not interested in maps, probably the competitor polar m450 is a better choice. For some reason I don't like the scheme that goes "no gps bike computer with connection to phone for gps" but it doesn't look like a really bad idea and it is way cheaper. Since I wanted a christmas gift i didnt check the cell phone bike mount, but I would have given it a try.

Also, keep in mind that for the price of a gps bike unit you probably can get a new cell phone with bluetooth and ant+, look that it has a good gps and battery life over camera quality or memory for instance, look that it is not very big and use it as a dedicated unit, but that would require research effort, and just getting a bike gps is more convenient.


Brakes won't stay tight I have plain ol' v-brakes and I have to tighten them all the time, every three or four weeks. I've been given to understand this is not usual. I'm not sure what's wrong though -- am I hitting them too hard? Could the pads be shot already? How would I know? I usually tighten them at the wheel rather than the handlebars, could this shorten their life?

The bike's about a year old and I ride it a couple miles a day in city traffic.

You need to figure out what's getting loose.  There are essentially 3 possibilities:

The brake pads are wearing down.
An adjustment -- either the twist adjustment, the cable clamp, or the pad itself -- is slipping.
The cable is "stretching".

If the pads are wearing that rapidly, it may be poor quality pads, or you may have some roughness on your rims.  It's also possible that your brakes are dragging all the time, due to improper setup or slightly "tacoed" wheels.

If an adjustment is slipping, you may just need to tighten a clamp tighter, or you may, eg, have an adjuster where the "bumps" that are supposed to hold it in place have worn down.

If a cable is "stretching" it's usually because the cable is breaking, strand by strand, and is in dire need of replacement.


Replace vintage barrel nipple Shimano shifter cable My West German bike has an old friction shifter. The shifting cable snapped and I discovered the nipple is barrel shaped but horizontal, much like a MTB brake cable, but smaller. I can't figure out what this is called to find a replacement cable. I guess I could get a new shifter if I can't find this cable type?
.

It's a Shimano Positron shift cable.
The outer housing is also special.

Picture from WorthPoint.com
I found a few for sale on ebay - not an endorsement.
There were two Positron systems. The first one was very complicated. The since there was no return spring the rear derailleur had two cables to pull back and forth. The later version had one solid wire cable that could both push and pull. That's why the cable end is so strange. The posted question refers to the second version of Positron.
There were many bikes sold with Positron shifting. For example, there was a version of the Schwinn Suburban in the late 70s that had Positron shifting with the FFS or Front Freewheel System.
Page 15 of the 1978 Shimano catalog has pictures and information.


What kind of pump do I need for this valve? This is the valve I have on my bike, but my current pump does not work with it. What kind of pump do I need to buy that will work with it?

That is a Presta Valve. Your pump, I am going to guess, is a Schrader Valve. You can buy a Presta pump from a shop or buy a $2 adapter.


How to figure out the BCD my chainring has I have a 2017 Diamondback Line. My chain has come off a few times and this post says get this chainring. I wanted to confirm my bike requires a 104 mm bolt pattern but don't know how to do that; the specs only say "Alloy arm with 32T single ring."

I may not need a new chainring, it's probably my shifting because it usually only happens when I am pedaling hard and in a higher gear (not sure if lower or higher but a gear that requires more effort to pedal) but lets assume I do.

The bolt center diameter is just the circle around the crank axle axis that the center point of the chainring bolts lie on.

If you have a even number of bolts the diameter is fairly easy to measure. Pick two bolts where a line between them goes through the axle axis. You can make some sort makeshift calipers if the crank arm gets in the way.

If you have an odd number of bolts you can measure between the axle and a bolt and double it, or if the bolts are evenly spaced measure between bolts and look up the BCD on this page.

When ordering a chainring make sure you get one which has the same bolt spacing pattern, although from this page I'd say you have evenly spaced bolts.

A narrow-wide chainring may help retain the chain, but they work best with a clutch derailleur. The reason you are having  trouble in higher gears (smaller sprockets) is that the chain is under less tension.

If you do order a narrow-wide ring, make sure it is compatible with the number of speeds of your drivetrain.


How to prevent trailer hitch bracket rotation? I am using a croozer kid bicycle trailer with a solid rear axle (shimano nexus 7). The hitch is the kind that goes on the rear axle between the left nut and the anti-axle-rotation nut for the gearhub.

The problem I'm having is that seemingly no matter how tight I tighten the rear nut, I am unable to prevent it from loostening and allowing the hitch bracket to rotate about the axle.

Has anyone else had success with this on similar trailers? I am fairly certain the nut will strip if I tighten it any further, and I'm very worried the bracket (and frame) are doing damage to the axle if I ride with it while loose.

We are carrying only a newborn baby; the trailer is not overloaded.

Does anyone have a solution for this rotation problem? Thread lock? Anti-lock washers? Maybe a split nut?

Based on the image of their hitch that I found and added to your question, you're going to have to modify the hitch to make it work. It's designed to rotate (I don't think that's a good decision, but that's what they did).

If you have enough clearance between the trailer and your rear wheel/mudguard, you could rotate the hitch forward and clamp it to the chainstay. I'd use a jubliee clip (hose clamp), and leave it there permanently. The problem with that is that you won't be able to remove the rear wheel without removing the clamp. If the chainstay sticks out past the dropout it's also going to bend the hitch when you do the axle nut up, which I would not do.

The other option is welding a bump/tab onto the inside of that clamp as described by solson. I strongly suspect that mount is steel, so it's easy enough to weld onto. If you don't have a welder it's going to be 10 minutes work for a metalworker to do it, plus you will need to repaint the hitch afterwards. I would buy a second hitch for this, since Croozer sell them, and that way if you stuff it up you can still use the existing hitch. If you're paying, clean as much paint as you can off the whole hitch (welding will heat the whole thing up and burn off paint over much of the hitch, which is stinky, so if you don't do it you're going to be paying someone else to do it). Then work out exactly where you want the tab and scratch marks along each edge, from the hole in the middle right out and down the outside edge (so they're visible after the weld covers the scratches on the inside surface). The welder will put a blob that extends past the scratches (molten metal doesn't sit in nice box shapes), then you will file it back to get nice straight edges that will lock in place nicely. If the metal place is able, oil quenching after welding will harden the bracket which will be helpful.

What you're trying to get is the red blob added on the dropout side of the hitch, so it sits on the slot in your dropout when the wheel is installed.


DNM USD-6 fork service intervals and procedures What are the good service intervals for the DNM USD-6 fork? How to understand that it should be maintained first? What are the recommended procedures for this?

The manual linked in the comments states that the fork should be serviced every 10 months, every year or every two years, depending on its usage conditions, at an authorized shop.

The service intervals are expressed in terms of months of owning rather than in riding hours. However, the suggested maintenance intervals lie in the expected order of magnitude for values for how often people service their forks in the real world (from twice a year to once in two years, depending on the usage).


How to measure handlebar diameter? I don't know my bike's stock handlebar diameter. I am going to upgrade some parts, for handlebar I tried to read any information written on it but there is only it's brand name. Can you help me please?

EDIT: Sorry for my poor English. I am trying to mean the "diameter" by "width", like the cylinder here http://www.nordenexpress.com/images/packaging.gif (For example I thought- the drop bar I want to buy has a "length" of 44cm, not width. Sorry again)

My bike has a flat handlebar and I am willing to replace it with a drop bar. Drop bars I've found on online bike stores are mostly 31.8mm. I don't know how to measure the diameter of my flat bar, I don't have calipers. Even if I had calipers, I don't know where to measure; the middle of the bar is thicker, ends are thinner.

I am not sure about where is 31.8mm. Just thought maybe it is the diameter of the bar, am I right?

If a handlebar (like mine) is said to be 25.4, can you tell how we get the result 25.4? Measure the diameter? Radius? Periphery?

Is it a road dropbar or a MTB riser style bar? These two images should prove useful. If it is a mountain bike style riser or straight bar it's quite simple.

If it's a road bar most people (zipp) measure center to center of the drops.

Also if it is a Mountain bike were speaking of, most bars will be sold as 730mm or more wide and have pre-printed lines to cut them shorter. There is a lot of preference involved in bar length. I prefer a shorter length than a lot of people my size, some downhill guys prefer 800mm bars, too long for me, I'm good at finding trees! :P

A good reference if its a road bar is about shoulder width in the drops. This can vary with preference and riding style slightly but is a solid method for the best on bike ergonomics and comfort.


Using an LED torch as a helmet light, will I blind oncoming drivers? I'm planning on buying this LED Torch with this helmet mount.

Could I blind oncoming drivers?

I have a helmet mount very similar, and yes its totally possible to dazzle and annoy any other road user, from pedestrians to other cyclists to motorised vehicle drivers.

Benefits to a helmet light

Its high up above the ground and higher than handlebar lights, so other road users can see it over cars.
The beam follows your head, so you can light up the thing you want to see.
Retro-reflectors everywhere!  Since the light source is near your eyeballs, retro-reflectors work really well and from a very long way away.  A sweep across a dark road will illuminate all those car bumpers and street signs and mailboxes and jogger's jackets and sports shoes.

Disadvantages of and risks due to a helmet light

Drivers might get dazzled.   I've had a bus driver yell at me from his rolling bus because of my head light.  Admittedly he was more annoyed by the flashing, so after some research I decided to leave it on solid.
Retro-reflectors can be dazzlingly bright when lit up at close range, destroying your own night-sight.
Snaggage risk - your torch/flashlight is a fairly respectable-sized hook and can catch on low hanging branches.  I've caught mine on a washing line at low speed and basically "clotheslined" myself with the chinstrap.
Helmet Function may be compromised by the holder.   Michael Schumacher's skiing accident was exacerbated by the gopro camera mount that focused impact forces on one point rather than spreading them over the head like a helmet is supposed to.  If you were crashing, then the mount should snap off.  What if it didn't snap, or if you impacted vertically onto it?
Weight - torch batteries are dense and the added weight can be noticeable.

Comments

I have mine mounted fairly far back on the helmet, so the torch front barely clears the top.  This reduces snag risk.

The mount is held on by a minimum of velcro, and there's a separate hand strap used as a second line to stop it getting lost.

As mentioned, I use it on solid mode now, however the focus is set fairly tight.  At night my normal posture puts the lights on the road surface around 4-5 metres in front of my wheel.  I tend to look up with my eyeballs rather than my neck.

However, if a car presents in a manner that crosses my path and may require them to give way (to yeild) then I will point the beam below the driver's door.  If I'm passing a parked car that has a person moving in the drivers seat I might light up their wing mirror.

I'd rather annoy someone than get doored by their inattention.
While I won't deliberately dazzle anyone or anything, my priority is everyone using the road arrives home safe.

EDIT Here's a pic showing what I do, for clarity.


Friction shifting 9 speeds using an 11 speed rear derailleur I am interested in running a 1 x 9 drivetrain using an 11-speed Shimano 105 R7000 rear derailleur. If I'm friction shifting 9 speeds, will using an 11-speed derailleur cause issues? Or is it as simple as setting the limit screws to the proper positions. Would I need to use an 11-speed chain because of the derailleur?

It won't necessarily just work, and there is a way of predicting whether it will with good accuracy, barring a borderline case.

If it's a Shimano 7, 8, 9, or 10 shifter in friction mode, it probably won't work.

Friction shifters have some variance in their total cable pull between models. It's easy to measure by marking the cable and using a ruler or caliper to note the total movement of the mark.

Take that total cable pull number and multiply it by the actuation ratio of the rear derailleur. For Shimano road 11, it's basically 1.4. That number has to be equal to or greater than the total cog-to-cog distance of the cassette, which for Shimano 9 is about 34.8mm. If it's less, the rear derailleur won't have enough total movement.

The reason there can be borderline cases is because rear derailleur movement for a given input is actually a curve, not a perfect ratio, and the exact start to finish value is going to depend on the high limit setting. But it's pretty close to just being a ratio.

A 7/8/9/10 Shimano shifter in friction mode has a little bit of movement beyond where its last detent position would have been, but not very much. Since these generations are designed to pair with a 1.7 actuation ratio rear derailleur, that small bit of movement is not likely to be enough to compensate for the fairly large difference in actuation ratio.

I don't have any experience putting 9-speed chains in 11-speed derailleurs. Sometimes that direction of mismatch can cause rub between the derailleur inner cage and the chain. 9 speed chains don't tend to experience this in 10 speed derailleurs and 11 speed chains are only something like 0.2mm narrower than 10, so 0.1mm per side. It will probably be fine to run 9 but you could do 10 or 11 to be safe. The shifting may be laggier but it's unlikely to matter with friction.


Should unconventional colors be avoided for lighting? Red/amber lights in the rear of the vehicle, white lights, in front of it: that is the good old convention and certainly switching their places is a bad idea.

A quick search, however, shows other colors available to purchase. Concerning "to be seen" bicycle lights, should they be avoided?

More specifically, I would like to have one blue light in the front of my bicycle (just because I find it more pleasing), but am I asking for trouble if I replace my white light for the blue light? Would it be a better option to use both?

A quick search, however, shows other colors available to purchase. Concerning "to be seen" bicycle lights, should they be avoided?

Yes, they should be avoided.

First, off-colors might not be legal in your area.

Second, and more importantly, no one will know what it is.  If a driver sees a flashing red taillight, or what looks like a normal white headlight, that driver is likely to identify you and your bicycle.  Something like a blue light is likely to evoke a, "Huh?  What's that?"  Which means most drivers won't treat you like a known entity - something they need to avoid.

And what do drivers (and cyclists, for that matter) do about things that don't evoke a familiar "must avoid" response?  You won't even register as being there.  Think about it - how many random items to you ride past all the time?  Do any of them really register at all?  Trees, mailboxes, plants, fence posts - they don't meet your brain's "must avoid" pattern, so you don't react to them at all.

You do not want to be cycling in the dark where you need lights so you're seen and safe, and then do any thing that makes it harder for others to identify you as a bicyclist.


Bike weight limits, fatter tyre for more weight? I have a touring bike which I use for commuting, I carry about 30 kg of tools with me usually on this pannier type thing I made on the back. And usually a work belt on the front which is 7 kg

 I'm wondering how much more I can safely carry on the bike without stressing it too much. The tyres seem to be under a lot of strain in particular. I'm 75 kg, unloaded with just me the bike tyres look fine, when loaded they're flattening out to an alarming amount.

I just ride on the road, but they're not good roads, I want to add about another 20 kg of tools and I'm wondering if I should put a fatter tyre on the back. I have 29 inch tyres on my mountain bike which look like they might fit. Or whether I'm worrying needlessly?

The flattening is normal, since there is so much weight. Don't really try the MTB wheels. They will probably not fit and you will have to be rolling with different sizes of tyres that may not fit to the frame. Increase the air pressure (or go tubeless) and make sure you change tyres in short periods of time. Don't let them wear totally off.


Where is the valve in my handpump - and what stopped it working? I have quite an old handpump that fits on my frame.

It looks like it's called TOPEAK  "miniDUALG - optimised for MTB/ROAD."

It has a pressure guage and various bits that screw the handle to the body and the body to the end with the pressure/bar valve, with an interchangeable head that allows you to switch between Schrader and Presta / Woods/Dunlop valves.

Last night, when I got a puncture, it wasn't working. The pump was placing as much resistance to pumping in as pulling out (I may even have been drawing air back out of the tyre, I can't remember).  Somewhere, there must be a blockage which is stopping the one-way valve from working.

But where is the air intake for the pump anyway?  In the head (part of the valve adaptor), the middle (it has two sets of o-rings, with some cleverly designed stuff between them), or the handle (which has gaps in the screw thread down which air might flow from the outside — if that cup-shaped head seal would let it).

Anyone got any suggestions?  I'm baffled - but I don't want to throw away a perfectly good bike pump if I can repair it.

If I understand correctly you're feeling the same pressure on the compression stroke as the extension stroke?

The mini dual g pumps air during both compression and extension strokes so this would be normal behaviour https://www.topeak.com/global/en/products/pumps/239-mini


Can a greasy chain cause the chain to come off the rings? I heard once that you should clean your chain with a light degreaser whenever it looks especially dirty or at the very least once every few months. But that doesn't account for frequency of rides or miles ridden!

I've been riding my road bike over 100 miles per week for the last month and have been meaning to clean my chain anyway... and then...

The past week my chain kept popping off the chainrings. Four times out of five it was while shifting from the small ring to the big one. I believe it also happened when accelerating from a pretty low speed, like just at the crest of a very steep hill.

I'm going to clean my chain anyway, but I'm just curious: could a very dirty chain be causing it to pop off the rings? Or could this be a problem of technique? Or do I just need a general tuneup?

No.  A greasy chain won't cause the chain to pop off, and it would have to be exceptionally dirty for dirt to cause this.  (I've ridden many miles with greasy, dirty chains.)  Generally a chain comes off due to maladjustment or because of a worn component (usually a cog).

Poor technique can contribute to the problem, but the technique either needs to be pretty bad or there needs to be another contributing factor.


Changing wheel size when adding ebike kit to tricycle I have a 20" wheel trike I plan to motorize. Can I add a 24" or 26" Hub front wheel motor and can I mix the front and rear tire sizes?

What are the consequences for stability and cornering?

I am new to e-biking and would greatly appreciate any guidance.

This answer addresses "stability and cornering"

If you do motorise your trike with a hub motor, it will gain 2-5 kilograms in the middle of the wheel.  This is "unsprung weight"  Depending on the battery number, size and chemistry you will also add 0.5-10 kilograms of storage somewhere on the frame.

So your bike will get heavier by ~3-15 kilos.  This is balanced out by the assistance provided by the motor as long as you have power, for regular straight-ahead riding.

A hub motor in a regular bike's front wheel aggravates any conditions.  If you ride in the wet or on damp leaves, its more likely to slide out under you.   I've never ridden a rear-hub motor, but I imagine its similar, and powering through any corners is a bad idea.

The motor is also unsprung weight, in vehicle terms that's the weight that is always pressing on the road with no suspension.  Increased weight makes jumps much harder, and increases the impact of anything like potholes and road debris.

A test you can do is to get some weights that are about as heavy as the kit you want to fit, and got for a ride with these weights on your bike.  Bags or plastic bottles of water might be safest.  This will show you about how it will feel if the battery is flat.

Personal story - I had an electrified MTB for a while, and it was capable of 40+ km/h with pedalling.  I had multiple instances of cars seeing me in the distance and pulling out without anticipating my speed.

Now I have a road bike and can get to similar speeds without the boost, and because I look faster then cars have been less likely to pull out.

I also found it was too easy to take corners at speed.  Several times I turned 90 degrees and found myself halfway across the car lane, because I was riding to preserve my momentum.  Once I was clear on the wrong side of the road, and fortunately only good luck meant no cars were oncoming.

Summary - ebikes are a gateway drug into riding your bike more.  They're a sop to the conscience for those who want to but can't quite.... as such they do have a place in cycling.

Changing the wheel size is well covered in other questions, like:

Kid's bike - Can I put 20" wheel on a frame that was meant for 18" wheels?
Can I change my 28" wheels for 24"?
Can I run a 700c/28"/29er wheel & tire on a 650B full-suspension mountain bike frame?
Can I swap a 29er fork inplace of a 27.5 if I maintain close to the same axle to crown length?

Short summery is "maybe" if it fits without rubbing, but brakes may be an issue.  Geometry of the bike is also changed in various ways.  I'd expect your forks to be too short for a larger wheel, so you're up for replacing them too, if the trike has forks.


Required 26.8mm diameter Seat Post I have a Schwinn Searcher Sport 2011 Hybrid Bike, with a damaged seat post.

Thus, I require a 26.8mm seat post with suspension. In India, I have searched, but I am not able to find a suitable seat post.

How can I obtain a suitable seat post?

I would suggest any site like Amazon, EBay, or craigslist even. I just skimmed through and Amazon, as well as EBay have a good assortment of seat posts in that size.

If you want an actual bike shop website, try using Wiggle. It is something of a surplus store, so they have a pretty decent selection at decent prices.

Your seat post size seems to be fairly common, so I don't think you should have any problems finding something that works for you.


Selecting a front derailleur: parameters The spec sheet for the Shimano Alivio FD-M430 front derailleur contains a number of points that I don't understand.

What does "Maximum capacity: 22 teeth" mean?
Why are "Top gear teeth" constrained to "44/48T"? Is there anything wrong with 46?
What is "Cable Routing: dual-pull type"?
And most puzzling, what is "Chain Stay Angle  63-66 / 66-69" and how do I measure mine?

Derailleurs, fortunately have been fairly standardized. Simple specs like these can help you determine what derailleur is best for your bike. Here's a brief overview of some of these:

Maximum capacity: The maximum number of teeth between the largest and smallest rings. eg. 48T-22T = 26T.
Top gear teeth: The range available for the largest ring. Any size ring in this range will work. Even some rings outside this range may work, but not to their best potential.
Cable routing: Derailleurs come in multiple pull types:

Top Swing: The clamp is below the cage and the cage pivots above the clamp. The cable attaches from above.
Bottom Swing: The cage is below the clamp and swings from below the clamp. The cable attaches from below.
Dual Pull: Can pull from either direction.

Chain Stay Angle: The chainstay angle is the angle between the chain stay and the seat tube. The derailleur must fit this angle or risk the cage hitting the chain stay.

Of course, Sheldon Brown has some good information, but if you really want to dive into all those numbers, have a chat with a mechanic at your LBS. I didn't know anything about these angles until my mechanic pointed out that my seat tube angle changed near the BB and meant I should have a bottom swing instead of the top swing I bought. It works, but doesn't provide the best shifting possible.


Grip shifter difficult to move in one direction i was wondering if anyone has an idea of what my issue is exactly and how i can fix it

the gears are super difficult to switch, 6 to 5 is difficult but still doable and going from 5 to 1 is just not happening, however when it comes to going in the other direction the lightest touch will make it go from 1 to 6

any idea how i could fix this?

This is almost always caused by friction coming from the cable housings. The reason is that in one direction the shifter is pulling the cable through the housing and must overcome any friction, which could be caused by contamination, corrosion, tight angles, and/or fraying. In the other direction it's releasing cable and does not have these forces to overcome.

You can test whether this is the case. On most bikes this is done by shifting into the lowest gear, then, while not riding or turning the cranks, shift the right shifter into the highest position. This creates slack in the rear derailleur cable. Grab the rear housing loop and pull it out of the housing stop on the chainstay. Do the same with any other housing stops you can. Then try working the shifter back and forth to see whether the friction is gone. While you're doing this you can do a simple clean and lube of the cable, which there are many guides to here, and depending on the cable layout you may be able to visually inspect for issues. Afterwards you can use the above steps in reverse to put it back together.

If the test revealed the problem to be cable friction, but cleaning and lubrication doesn't fix it, replacing the cable and housing is needed.


When to replace rear derailleurs What is the typical life cycle of mid-range rear derailleurs assuming no accidents? More precisely, what's the average mileage after which it's better to replace it rather than doing tuning all the time?

Derailleurs will last almost indefinitely. The jockey wheels will wear out in time (tens of thousands of km) but the rest of the mechanism shouldn't see significant wear.


Buying brake levers, how do I find the correct ones for my bike? I took a hard spill the other day on my mountain bike and snapped my left hand brake lever in to pieces.
The ones that snapped are stock alloy rubbish that came with a Specialized Hardrock 2010 Disc Brake model.   They are standard Bowden Cable brake wires with the little barrel shaped bit at the end that fits to the brakes.  (Do they have a name?)

I'm having some trouble purchasing levers and there doesn't seem to be much information on it online or much information on the products I'm finding.

To the point

What I need is Bowden Cable compatible brake levers but I have no idea how to search for them.  Sometimes descriptions will mention that they are for pneumatic, V-brakes, caliper or canti brakes but I've never seen anything saying that they would be compatible with my bike on any site.

What am I doing wrong? Or what should I be searching for here?

Since it sounds like you have mechanical disc brakes (Avid BB5 or Tektro Novela not hydraulic) then any direct-pull or V-Brake lever should work fine with your cable. Searching for 'V-Brake levers' or 'mechanical disc brake levers' should provide plenty of responses.

For example, if you look at the spec page for the Avid FR-5 lever, you will see that they are compatible with both "Mechanical disc brakes, Linear-pull brakes." V-Brakes are a type of linear-pull brakes.

Note that most levers designed specifically for Cantilever Brakes will NOT be compatible. The key issue is that the levers must be direct or linear pull.  Some brake levers (e.g. Shimano's ST-EF60 shifter+brake lever combo) are switchable between canti's and V-brakes. If you don't set them to V-brake, you're not going to pull enough cable for proper braking.


Is the front center pull brake supposed to be free floating? I have an old Motobecane (see this picture from another person's question)

The brake assembly which is attached to the front forks doesn't move.

As I recall, on other bikes that I have had like this, the front brake caliper unit rotates on the bolt that attaches it to the forks. When the brake pads clamp on the rim, the brake assembly centers itself each time you brake.

On the Motobecane, it's fixed in place...Is it supposed to be "floating" or rigid?

There are two types of caliper brakes, the side-pull and the center-pull. You have the center-pull but are used to side-pulls.

Side-Pull

You're used to the side-pull. There, the cable comes to one side and squeezes the arms together. Because it's not symmetrical, it uses the pressure of the brake shoes when full-squeezed to center itself around the single mounting pivot. By design, the entire brake can pivot around that mounting bolt:

[

Center-Pull

Your photo shows a center-pull caliper brake. It uses a straddle cable that goes to a yoke (both of these are missing in your example but can be seen below). The straddle/yoke design tends to self-center -- at least if the straddle cable isn't too deformed with age. The brake arms themselves don't pivot around the mounting bolt, but instead pivot on the pivots on the left and right side of the mounting assembly (they had red washers in the photo below). Because of the dual-pivots there is no need for the mounting bolt itself to pivot as part of the brake's normal operation. You can loosen the mounting bolt to recenter by eye and then tighten it back up, but it doesn't float around the center the same way as a side-pull:

[

Both images from wikimedia commons.

A footnote...

Furthermore, I should note that these brake designs from the 1970s were built with much larger brake pad clearances than contemporary brakes. Your shoes might float a good 3-7mm above the rim on either side. Compare that to contemporary brakes which have very close rim clearances, just 1-2 mm. This means that you don't have to be as precise centering with these older brakes -- and you should allow more pad clearance than you might be used to if you have a contemporary bicycle as well. And you'll never get these old brakes to brake as well as a contemporary brake, they will always be weaker and more rubbery in feel.


Sticky/Not fully returning ultegra r8070 brake lever Got this used di2 equipped bike with what seemed to be just a spongy front brake. Bleeding as per manual. Still "mushy". Emptied the line and disconnected the hose. The lever just don't return all the way back on its own. Removed the lever from the bars and can't see any obvious problems. It just moves half way back after being pressed normally and slows down in the second half of the travel. Then stops at about 1mm from the proper position. And I can push it to return. Pressing it quickly a few times makes it snappy again for a few returns and then it slows again.
My guesses went from cylinder, to dirt, to di2 cable stuck between the springs or the springs mounted incorrectly but just impossible to understand what's going on inside without removing the lever. And I'd rather not just dump a degreaser or wd-40 into a di2 brifter...
Any clues or similar experiences?
Update: took it to another LBS and the owner said he has "a friend that works for Shimano" so I left it there ATM for the "friend" to check.

The range of travel where it's having trouble sounds an awful lot like the same range of travel that makes up the difference between the minimum and maximum free stroke setting. I haven't seen this issue and my understanding of how the free stroke mechanism on these works isn't perfect, but the first thing I would look at is whether the free stroke hardware seems to be in order and how it responds to that adjustment.


Choosing a rear derailleur for 11-42t cassette on a SRAM 10-speed 1x system I have an 11-42t 10 speed cassette and a 42t narrow wide chainring. I cannot work it out definitely whether a Sram long cage rear derailleur will work with it.

I think that this one should work but if someone clever could confirm and/or recommend something better, I would really appreciate it: SRAM GX Type 2.1 10 Speed Rear Mech.

It's a road/gravel/commuter bike with bullhorn bars that I'm building myself. Its the first time I've built a bike and has been a steep learning curve which is part of the reason I'm doing it, buts its very fun.

I know there are loads of similar questions on the internet but I've trawled through hundreds and there seems to be so many inconsistencies and exceptions in the answers.

One confusing thing here is that SRAM themselves, that I know of at least, have never made or warranted a 10 speed 11-42 1x setup. So you're not going to hear from them or their product documentation that any SRAM RD will work here.

There are two questions. One is capacity, which is the total amount of slack the RD is capable of taking up. Different cage lengths are what gives you your different amounts of capacity. SRAM doesn't publish actual capacity numbers like Shimano does; they make you infer it from looking at their Compatibility Map documents. Because you're using a 1x, the capacity you need is simple to calculate: it's large cog tooth count minus small cog tooth count. For 2x or 3x, you're adding to that number the difference between the large ring and the small ring. So by looking at the Compatibility Map, we see that you actually only need a medium cage, since their capacity is sufficient for use with a 14t difference in front (42/28 double) plus a 21t difference in back (11-32 cassette). So at least 35t total capacity, whereas you only need 31t. Long cage would still work, but you don't get any benefit from it here other than versatility if you want to change things later, and the drawbacks are weight, ground clearance, and arguably shifting performance.

Note that sometimes things can get awkward when one flirts with maxing out the total capacity of a rear derailer on a 1x, because then you're riding with the cage pulled all the way forward when in your big cog, which tends to add friction and decrease shifting performance. Here it should be fine, this setup with medium cage is more or less a known quantity (Wolf Tooth and OneUp both say it's a go with their 42t conversion cogs, for example) but in other cases I'd be cautioning that putting it all together is still going to be a bit of an experiment. Also note that chain growth is a factor that has to be managed on some full suspension bikes.

The other issue is largest cog clearance. SRAM says the max for their 10-speed derailers is 36. In practice lots of people run them with 42t cassettes, either ones that come that way or are modded with aftermarket large cogs. It's possible that to get the pulley/cog gap required you may need to swap in an extra-long B-tension screw, which is just an M4x0.7 bolt. Note that SRAM 1x setups need kind of a lot of clearance here. I'm always a little baffled about the physics involved that makes a bigger gap work better, but it's true. In theory since you're putting the clearance out extra far here, shifting performance may suffer at the other end of the cassette, but in practice that doesn't seem to be much of an issue.


Will tubeless tires out-perform my Armadillos on my commute? I have a Trek commuter bike (8.4 DS). I bike 5.5 miles to work, and up to 15+ miles home. I’m considering the switch to tubeless. Most of my commute (all but 1.5 miles) is on a well-maintained concrete trail. For that 1.5 miles, I’m in gutters or hugging them on residential and downtown streets. I’ve had no flats in the past year of commuting under those or similar circumstances. But I’ve read and heard that I may get better performance from tubeless tires. I’ve also heard the opposite. My Armadillo (Kevlar™) tires have probably seen around 2000 miles over the past 6 months, and my back tire is going bald (under my weight and the additional 5-to-15 lb. load of my pannier). With that in mind, …

Will I recognize any worthwhile performance advantage from switching?
Do tubeless tires tend to go bald any faster or slower than Kevlar tires?
Could I expect more or less flats with tubeless than with my Kevlar tires?

P.S. In case weather is a consideration, we have little enough snow and rain here in Topeka, Kansas, that I am not worried about weather-related performance issues.

Bald-ness isn't a problem on tires used on roads. In fact, it's favorable. I'd replace the tire once I start getting flats (or a bit before), or seeing canvas.

The primary advantage of tubeless would let you run lower pressures (since you can't pinch flat a tube if it isn't there) which is useful for running big tires while mountain biking for more grip and comfort, but it won't really make a difference for commuting use (smaller tires at higher pressure).

The best thing you can do is have a properly inflated tire and buy a durable tire (e.g. the Schwalbe Marathon line) -- low inflation can lead to rim damage and increased wear, while overly high inflation can also lead to damage, less comfort and loss of control. A properly inflated tire shouldn't see many flats in either case (road debris will be the primary cause , which sealant may protect against in the case of a tubeless tire).

I'd stick with a tubed tire; tubes are relatively cheap and are easy to replace on the side of the road with slightly less mess than inserting a tube in a tubeless system. Note that you'll likely be paying a bit of money to go tubeless overall (e.g. with the Bontrager TLR kits).


How do I keep smallest gear on my crank shaft from contacting frame I have an old Trek 8000 ZX that I am fixing up. I had to replace the bottom bracket and I believe I successfully did that. The bike did not have a crank set to work with so I salvaged one from a pile of other old bike scraps.

My problem is when I attached the crank arm and tried to spin the pedal, the smallest gear just rubs against the frame.  It appears that the crank is too close the frame. It is just making contact 5mm would address the issue.I want to know what my options are. My initial guess is to find a crank set with smaller gearing and hoping to find one that fits. The other idea is try and get a spacer but I am not sure how safe that would be.

There are number of bikes available that I could steal parts from but I would like some guidance on what I should be looking for in terms of size. I am not sure of the age of the bike, but I am pretty sure the frame size is 21". The color is yellow if that helps.

I am sorry if some of my terminology is wrong/crude, I am new to bike repair/salvage (Having a blast though).

Thanks in advance.

Welcome to BB standards hell...... you are about to learn far more than you wanted to about bicycle gearing cranks and chain rings.....The only spec I could find on these was the 1999 model, which used a Shimano BB-UN52, 113mm spindle BB Shell Width   73mm - its pretty common and typical of that era MTB.

Your idea of another crank set is a possible solution, that might be easier if you have a supply of donor bikes, is a larger small chain ring.

Its likely though you need a longer bottom bracket spindle, as a short spindle will not only cause this to be a problem, but will affect the chain line. With incorrect chain-line you may have problems with getting gear shifts to work smoothly and reliably, and have problems with chain drops.  Read up about chain line Here (as always, Sheldon Brown)

Presuming its square taper BB, they come in a range of lengths. You should be able to measure your current length, and might find a longer one on your donor bikes. Hopefully the one you have now is around 106mm, meaning all you need to do is source the correct 113mm sized one.