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.