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29 votes
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Why are bolts on bikes so wide?

M5 is used far on far heavier luggage too, like rear racks. You don't want too many sizes to keep in your spare parts (I carry a couple of M5 and a couple of M6 screws on the bike in my toolkit, plus ...
Chris H's user avatar
  • 59.6k
23 votes

Stuck pedal, I've tried everything

I think your pedal is a lost cause. Even if you did get it off in the current condition, reinstalling and later removal will make later-you hate current-you. I would disassemble the pedal from the ...
Criggie's user avatar
  • 125k
19 votes
Accepted

How do I remove a severely stripped/rounded-off Allen/hex head bolt?

I can suggest three methods. The mounting clamp has a gap. You can use a thin saw to split the bolt there. It might scratch the clamp, but with careful action, the saw blade will not touch the ...
Grigory Rechistov's user avatar
14 votes
Accepted

Why are bolts of brake discs using Torx sockets?

The magic of lobes allows Torx to handle a given torque value with a shorter bolt head than the alternatives, and some frame/fork designs need the clearance in this area. That's the only reason for it....
Nathan Knutson's user avatar
14 votes
Accepted

What tool do I need for this bolt that holds the crank arm on this stationary bike?

That nut was put in the wrong way around. This is what the nut looks like: The hex end is what you should tighten with a approriate socket. This is what it should look like when installed correctly: ...
abdnChap's user avatar
  • 3,339
14 votes
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Threadless handlbar stem bolts - grease, threadlock, anti-seize, or dry?

Any of the choices except dry will be fine in most use cases. (This assumes a medium strength threadlocker). Lubrication on torque-sensitive fasteners is important. When your goal is to achieve a ...
Nathan Knutson's user avatar
12 votes
Accepted

A small bolt/nut came off my mtn bike while washing it, can someone help me identify it?

Arghh! got it. thanks for all the input(im the OP) I looked over everything I thought super closely but ended up test riding and found its the bolt from my dropper lever(old specialized command post)...
Mw3841's user avatar
  • 209
11 votes

Why are bolts on bikes so wide?

Not everything is designed at its theoretical maximum strength. There are always practical reasons for any engineering choice, including "mundane" things, like the fact that I can buy M5 ...
BetterSense's user avatar
  • 3,406
10 votes

Why are bolts on bikes so wide?

Most of it comes down to fatigue. Even M2 bolts will hold a bar to a stem long enough to make it around the block, but when you need to withstand pothole after pothole the failure method you are ...
thanos's user avatar
  • 101
10 votes

Stuck pedal, I've tried everything

I would try removing the crank and clamping the pedal in a bench vise. With the pedal pointed downward and held very firmly in the vise, you’d then try to turn the crank clockwise. Otherwise, the ...
Pisco's user avatar
  • 773
9 votes
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I stripped one of four bolts on the faceplate of my stem. Is the stem usable until the replacement arrives?

This really is an opinion more than a factual question. That you still have three bolts means its held together, but it was designed with 4. So there's a non-zero chance another bolt will go because ...
Criggie's user avatar
  • 125k
9 votes

How to remove a seized & snapped bolt and extractor from a welded titanium cage boss

The first thing I would do is assess the question of what happens if your efforts result in the eyelet threads getting wrecked. Is the eyelet and its welded connection chunky enough to fix it by ...
Nathan Knutson's user avatar
9 votes

Stuck pedal, I've tried everything

I know this situation myself. The pedal shaft is hardened steel. It will win. Taking into account what you tried, expect the thread in the crank to be lost even if you get the pedal off, eventually. ...
Fred's user avatar
  • 221
9 votes

A small bolt/nut came off my mtn bike while washing it, can someone help me identify it?

Could be the "nut" for a bolt mounting a chainring to a spider. Here's an example of a pair: Perhaps a similar "nut" for one of the rear derailleur jockey wheels. Perhaps a ...
Armand's user avatar
  • 2,835
8 votes

Left crank keeps coming loose

I’m assuming you have a square taper bottom bracket + crank arms? See this answer: Square taper crankset develops play after changing bottom bracket If you’ve been repeatedly riding with a loose ...
Michael's user avatar
  • 27.8k
8 votes
Accepted

How can I find replacement part for Mongoose scooter?

It looks like a quick release seatpost binder You might have a bicycle with one on it you could use to test the fit. Googling "bicycle seatpost quick release M6 × 65mm" gets results Here's one on ...
David D's user avatar
  • 21.5k
8 votes

Is my carbon fork steerer tube damaged by overtightened stem bolts

In practical terms, it's impossible to tell for sure in a case like this. It's probably fine, but there's no way of knowing absolutely via visual inspection. The surface indentations from the stem ...
Nathan Knutson's user avatar
8 votes

I stripped one of four bolts on the faceplate of my stem. Is the stem usable until the replacement arrives?

Answer this question for yourself: WHEN the stem fails, what's going to happen to me - AND EVERYONE AROUND ME? And only ride in ways that you're willing to live with the answer to the above question. ...
Andrew Henle's user avatar
  • 10.6k
7 votes

Rear derailluer broken bolt

This looks like the Syntace 142 mm X-12 axis bolt that also serves as the derailleur hanger. See https://www.pinkbike.com/news/syntace-142mm-12-norco-2011.html Syntace catalogue (there are several ...
Vladimir F Героям слава's user avatar
7 votes

How to Remove Square Taper Chainring Bolts

The rings are not replaceable. You can remove them with a drill if required. This type of chainset is very cheap and quite heavy. It would cost significantly more to replace the rings than to replace ...
Noise's user avatar
  • 14.1k
7 votes

What is this "padding" on screws?

Re-answer (based on Szabolics' link in the comments): It appears to be either a (now weathered/aged) moisture seal to prevent water from getting into the caliper mounting threads OR a a crude ...
Ted Hohl's user avatar
  • 6,357
7 votes

A small bolt/nut came off my mtn bike while washing it, can someone help me identify it?

I wonder if it's part of a clamp for a brake lever or shifter lever, and has dropped out of the handlebar area. Pushing/pulling/prodding should show a surprise loose item, and go from there. ...
Criggie's user avatar
  • 125k
7 votes

A small bolt/nut came off my mtn bike while washing it, can someone help me identify it?

My 2 cents is that it is from a clamp of a lock on grip. I have a set of WTB ergonomic grips that have lock on clamps on each end. The notable thing about the clamps is that they are built in to the ...
Jeff's user avatar
  • 10.5k
7 votes
Accepted

Sheared off kickstand bolts. Repair shop recommends drilling the chainstay, should I try the bolt extractor first?

You'll only have one shot at this repair and have to do it right, twice in a row. As such I see two "safe" options. Send the frame to a bike shop or someone handy with tools who has done ...
Criggie's user avatar
  • 125k
7 votes

How do I remove a severely stripped/rounded-off Allen/hex head bolt?

Drilling out the bolt is probably difficult, because handlebars are not easily fixed to something rigid, and you have to drill freehand, in an unusual direction. At least, use some lubrication and a ...
Peter's user avatar
  • 71
6 votes

How can I un-seize track nuts?

I would use the same techniques as used on rusted hardware. Liberally apply a penetrating oil (liquid wrench, PB Blaster, CRC Knocker Loose). Use a penetrating oil not a lubricant to break them loose. ...
mikes's user avatar
  • 18.7k
6 votes
Accepted

Skipping bolts on seatpost , please help?

₹ 555 (Indian Rupees) is about $11 NZD or about $7.50 US, 5.64 UKP or 6.27 Euros. So you've got a seatpost that is incredibly cheap and likely made of low-grade metals. Zooming in a bit shows the ...
Criggie's user avatar
  • 125k
6 votes

I stripped one of four bolts on the faceplate of my stem. Is the stem usable until the replacement arrives?

Dont use the stem , its rated at 4bolts@ 6nm , by putting in the 3bolts you may need to over tighten one of the other bolts to compensate for the same level of clamping force which may distort the ...
binaryOps20's user avatar
6 votes

Handlebar slips in quill stem clamp when going over bumps

A few things to think about: Are you using grease or threadlocker on the bolt threads? This will minimize corrosion and galling problems, and means that the same final torque value is actually ...
Armand's user avatar
  • 2,835
6 votes

Why are bolts on bikes so wide?

Apart from the practical advantages of having a low number of different bolt sizes, and the tensile strength that you cite in your question, there is also the rather underestimated fact that bike ...
cmaster - reinstate monica's user avatar

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