I don't like to use force when doing things up, because if you do, how will you undo them?
How would I undo the crank bolt? I'd just ride the bike around for a bit, and my legs would magically loosen it.
The cranks do (and should) naturally squirm up the taper a bit, so after a while the bolt will be loose. You should not retighten it, because that way leads to cracked cranks.
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I'd rather have to cut my cranks of with an angle grinder (when the BB gives up) instead of re-tightening them all the time, but the cranks evidently don't like that idea.
If it isn't a horribly rude question, what do you weigh? And are you landing big jumps?
-- [email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/ Iraq war: it's time for regime change... ... go now, Tony, while you can still go with dignity. [update 18 months after this .sig was written: it's still relevant]
Oh, God, cotter pins. How I /loathed/ cotter pins. The square taper crank has to have been one of the best innovations ever. It seems to me I've been using them for about thirty years, and, while cotter pins *always* gave me problems, square tapers have been very, very reliable. I've never split a crank; I've very, very rarely had a bolt (or, in earlier times, nut) come loose accidentally; and, as I've said, I've had a grand total of two cranks come off (both non-drive-side) in those thirty years. As far as I'm concerned, square taper is something that Just Works[tm].
Maybe if they had usenet 30 years ago lots of people could have told you that they'd had no problems with cotter-pins. 🙂
As you know, the crank tends to squirm up the taper in use anyway, so preloading it excessively with the bolt is not necessary. And, in my opinion, one failure every hundred thousand miles ain't broke.
The crank could get damaged if it's too loose to begin with. Cranks can move back down as well as squirm up. It'll only continue squirming up if the bolt is repeatedly re-tightened (not normally necessary or advisable).
I'm not suggesting that anyone with no problems for tens of thousands of miles should tighten anything or refit, but to those people in doubt fitting cranks now: look up the recommended values and use a torque wrench.
Big jumps, no. Yes to small jumps without any suspension however.
And in the interests of reaching a conclusion here, I should probably admit to most of the landings being far from graceful...
The loading on your cranks, if you land even modest jumps ungracefully (and if like most mountain bikers you habitually do so with the cranks horizontal) is going to be pretty high. I suggest what you need is practice landing jumps gracefully.
Oh, God, cotter pins. How I /loathed/ cotter pins. The square taper crank has to have been one of the best innovations ever. It seems to me I've been using them for about thirty years, and, while cotter pins *always* gave me problems, square tapers have been very, very reliable. I've never split a crank; I've very, very rarely had a bolt (or, in earlier times, nut) come loose accidentally; and, as I've said, I've had a grand total of two cranks come off (both non-drive-side) in those thirty years. As far as I'm concerned, square taper is something that Just Works[tm].
Maybe if they had usenet 30 years ago lots of people could have told you that they'd had no problems with cotter-pins. 🙂
Oh, lots of people managed just fine with cotter pins. I didn't!
H'mmm... I've three square taper systems still in use. One's 18 years and about fifteen thousand miles old (cranks; the BB's been replaced at least twice, probably more times, and the rings have all been replaced);
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This is a mountain bike. Mountain bikes live in a world of granite dust, sand, mud and other nasties. The original rings were Biopace (version 2); I'm one of those odd people who liked Biopace very much.
Would a late 1980's Shimano 105, 170mm long, 130mm PCD, 5-arm, square taper, with 52/42 Biopace rings be of interest ? Modest wear, but I believe servicable. Either just the rings, or the complete with cranks.
I've had no problems whatsoever since doing this, although to be fair the few before (a long time ago) might not have been anything to do with lack of grease.
I've never had a problem with my own cranks loosening in over 25 years of using square-taper cotterless cranks. After ten years in the bike trade I'm only aware of one loosening problem with a crank I fitted - that had grease on the taper.
Which proves nothing, of course.
I cleaned it up and refitted it - it didn't come loose again :-)
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I've not seen any evidence of crank bolts routinely working loose when properly tightened. I've never split a crank. And I don't use dustcaps on my bikes, because they only trap water. I wonder why JB has had such a different experience.
Maybe he rides his bikes in an unusual way??? Monster gears up mountains, for a start.
I assumed he was talking from wider experience than just his own bikes - maybe that was incorrect.
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Anyway, I think the grease question is a red herring. I'm not suggesting that it is necessary, personally. The important thing is to make sure the cranks are properly tight -- then they won't come loose whether grease was used or not.
That's not my experience, although a single incident obviously isn't statistically significant.
Oh, God, cotter pins. How I /loathed/ cotter pins. The square taper crank has to have been one of the best innovations ever. It seems to me I've been using them for about thirty years, and, while cotter pins *always* gave me problems, square tapers have been very, very reliable. I've never split a crank; I've very, very rarely had a bolt (or, in earlier times, nut) come loose accidentally; and, as I've said, I've had a grand total of two cranks come off (both non-drive-side) in those thirty years. As far as I'm concerned, square taper is something that Just Works[tm].
Maybe if they had usenet 30 years ago lots of people could have told you that they'd had no problems with cotter-pins. 🙂
I've never had problems with cotter pins (except having to file them to fit). I also haven't had problems with square taper, but my son had, when he didn't tighten them up enough.
Both work well if you don't abuse them by shoddy installation/maintenance.
> H'mmm... I've three square taper systems still in use. One's 18 > years and about fifteen thousand miles old (cranks; the BB's been > replaced at least twice, probably more times, and the rings have > all been replaced);
Quoted message said:
This is a mountain bike. Mountain bikes live in a world of granite dust, sand, mud and other nasties. The original rings were Biopace (version 2); I'm one of those odd people who liked Biopace very much.
Would a late 1980's Shimano 105, 170mm long, 130mm PCD, 5-arm, square taper, with 52/42 Biopace rings be of interest ? Modest wear, but I believe servicable. Either just the rings, or the complete with cranks.
I've had a grand total of two cranks come off (both non-drive-side) in those thirty years. As far as I'm concerned, square taper is something that Just Works[tm].
Likewise. One was cottered (the cotter pin fell out when the wretched Andy Pegg decided to relieve the tedium of an unremarkable BHPC AGM by taking the bike for a spin round Eastway's BMX track), and the other was an XT Hollowtech...
Would a late 1980's Shimano 105, 170mm long, 130mm PCD, 5-arm, square taper, with 52/42 Biopace rings be of interest ? Modest wear, but I believe servicable. Either just the rings, or the complete with cranks.
The loading on your cranks, if you land even modest jumps ungracefully (and if like most mountain bikers you habitually do so with the cranks horizontal) is going to be pretty high. I suggest what you need is practice landing jumps gracefully.
Well, that's one solution. The other -- since nothing else consistently gives me problems -- is to just switch interface. Much as I'd love to be more skillful and able to land everything gracefully, I think I'd rather stick to just having fun and not worrying about my equipment.
1) get it tighter (I've always tightened them to *really* tight, honest).
Don't.
Do!
Depends on how long the implement is. When I was tightening them with 8 inches of leverage, as tight as possible worked just fine. When I got 2 feet of leverage, that wasn't necessarily true...
.... eventually I stopped fretting and bought a torque wrench. -- David Damerell <[email hidden]> Kill the tomato! Today is Second Wednesday, August.
Anthony Jones ([email hidden]'😉 wrote: >1) get it tighter (I've always tightened them to *really* tight, >honest). Don't.
Do!
Depends on how long the implement is. When I was tightening them with 8 inches of leverage, as tight as possible worked just fine. When I got 2 feet of leverage, that wasn't necessarily true...
... eventually I stopped fretting and bought a torque wrench.
I wonder if the reported tendency for left hand cranks to loosen is influenced by the fact that the right hand crank can be tightened against the transmission, but on the left you can only hold on to the crank.
