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Old 08-04-10, 05:41 PM   #1
pwdeegan
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irritating creak from BB/crank region...

in the last week, after some 800 miles of riding silence, my bike has developed an irritating creak in the bottom bracket/crank spindle area. the noise only occurs when the crank is under great stress/loaded condition, e.g., hauling a 75# trailer up a 9% grade, or 'sprinting' up that same grade without the trailer—anytime i'm putting a lot of stress (typically, when i ride, i do not mash the pedals).

working backwards from easiest to more complex, i tightened the pedals, crank bolt, and BB to spec (used my torque wrench). the set up is a Sugino RD2 crank with roughly 5k miles (and removed-and-reattached from the BB spindle about a dozen times); a Phil stainless BB with stainless cups; older Deore SPDs. after tightening it down, the creak can still be replicated.

i decided to really tighten it down, everything is at spec+; BB is at about 55-60'#s, crank bolt is at 40-43'#s, pedals won't tighten further. YET the creak still occurs.

i can also make the creak occur doing a track stand and then pressing one side down without moving (really jamming it down, and not just standing on it lightly; it occurs on either side). this makes me think of several of things:

1. the BB spindle is creaking/flexing. this is not good because it's an SS spindle, and there isn't much else i can do to make it not creak. on the other hand, my previous PW Ti 108mm-sym BB never did this under about 2.5k miles.

2. the frame is flexing at the BB shell. it's a steel Salsa frame, well-cared for, never wrecked, so i think this is unlikely; but still, i can flex the frame with enough force from my leg. the paint at the welds seems normal.

3. the BB cups, though tightened down to a crazy amount, is somehow still creaking, but i don't know why or how.

4. a combination of #1 and #2, maybe some part of #3---but again, i can't tighten it down further (seriously, i used an 18" bar to tighten to spec+).

5. is the crank flexing because it might be shot from too many re-installations? it appears to tighten down fine, and the insides don't look noticeably squeezed out or mashed up...

Would it make a difference to pull the BB and re-threadlock the cups? Should i just live with the creaking until something snaps? It just drives me a bit wonky that after only 800miles something is creaking but won't go away. Would a SS Phil Wood spindle be defective enough to go through some kind of slow-flex failure whose symptoms would include creaking?

All useful thoughts and guesses appreciated.

Last edited by pwdeegan; 08-04-10 at 05:46 PM. Reason: added #5
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Old 08-05-10, 04:08 PM   #2
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for the scant few brave enough to read my post who may have wondered what the solution (in my case) was, i'll end the suspense now. it's pretty funny considering the prolix of BF that no one posted alternate potential solutions (was it just so obvious? but BF loves obvious!).

first, another good site to help one think of solutions to the nefarious "creak/clink form the BB"—which could in fact be from anywhere, as the testimonials reveal, is:
http://www.jimlangley.net/wrench/keepitquiet.html

In my case the solution(s) was/were (in order of likelihood):
1. loose chainbolts (tightened)
2. SPD pedal clasp (not spindle; simply greased the pedals' springs/clasp bits and pieces).

Creak is GONE. #1 is the most likely source since 1) it's just the sort of thing to come loose at 800miles; and 2) the pedals have never been lubed in their entire 10,000mile usetime. The good thing is that the bike has now been through a deeply personal and meticulous (if also frustrating) tuneup. The bicycle is back to riding utterly dreamy. Hooray!
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Old 08-05-10, 11:34 PM   #3
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Quote:
Originally Posted by pwdeegan View Post
for the scant few brave enough to read my post who may have wondered what the solution (in my case) was, i'll end the suspense now. it's pretty funny considering the prolix of BF that no one posted alternate potential solutions (was it just so obvious? but BF loves obvious!).
Glad you found your own solution. You could have saved the effort of posting had you searched the forums and read the stickeys.

"Deeply personal tuneup"? TMI!
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Old 08-06-10, 12:31 AM   #4
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^ like i said, BF is committed to the obvious
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