Incessant creaking in BB?

Hello.

Crashed a few weeks ago and slightly bent my big chainring so it
slightly grazed the chainstay every rotation - because the bike is a
bit of a mishmash (old school custom steel cyclocrosser with
stronglight crankset), the clearance was only a couple of mm pre-crash.
Anyway, took it apart and just moved the whole BB right ie. gave the
ring a little more space to turn. Everything was fine until a few days
ago where the BB started creaking, especially under pressure on going
up hills and in high-tension gear ratios. VERY annoying.

Did I overtighten/undertighten the BB cups? Or is it something to do
with the cranks? Anyhelp would be greatly appreciated.

Thanks,


Jack.

Per Jack:
Everything was fine until a few days
ago where the BB started creaking, especially under pressure on going
up hills and in high-tension gear ratios. VERY annoying.

Did I overtighten/undertighten the BB cups? Or is it something to do
with the cranks?

Flip the bike over and look very closely at the BB for cracks.

I went through the same thing - finally stripped out the BB threads completely
on the drive side. Attributed it to faulty threads (which they were...) but
when I sent the BB module to some tech guys at the bike's maker, they found a
crack.

OTOH, I've been through three replacement modules so far. All have what *I*
would consider faulty threads - but the maker's tech people say they're "good
enough"... and the fushluggener things *still* keep creaking. I'm finding that
the drive side cup needs re-tightening after every ride. Then it's quiet for a
few miles, but seems to back out again. OTOH, maybe the threads are failing
bit-by-bit. I'll know in a few days.
--
PeteCresswell

On 9 May 2006 05:28:14 -0700, "Jack" wrote:

Hello.

Crashed a few weeks ago and slightly bent my big chainring so it
slightly grazed the chainstay every rotation - because the bike is a
bit of a mishmash (old school custom steel cyclocrosser with
stronglight crankset), the clearance was only a couple of mm pre-crash.
Anyway, took it apart and just moved the whole BB right ie. gave the
ring a little more space to turn. Everything was fine until a few days
ago where the BB started creaking, especially under pressure on going
up hills and in high-tension gear ratios. VERY annoying.

Did I overtighten/undertighten the BB cups? Or is it something to do
with the cranks? Anyhelp would be greatly appreciated.

The BB is probably undertightened, if you're lucky. It's also
possible to get this creak if the crank's not tight on the spindle,
though that's almost always a silent failure.

Suggested fix: Use a large crescent wrench (gripping the ring near
the bend) to gently move the big ring back close to where it started,
then remove the spacer that you installed, and retighten the BB to the
right torque. Grease the threads when you put it back in.

If the sprocket was bent enough that you'd have a significant chance
that it would break when you bent it back into position, then it would
almost certainly be too bent to ride. Since it's not, the bend is
probably going to be easy to rectify. (This is not to say that it
absolutely, positively won't break, but I doubt that it will. That's
just my opinion, based on a wild-assed guess since I can't see the
damage from here, of course.)

--
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