Hey, I'd appreciate any opinions on this extremely frustrating case.
Original setup: phil wood BB (bought new), sugino 75 crankset (bought used)
New set up: new protype bb, new sugino 75 crankset
on a geekhouse fixed gear
original setup had spindles dry and clean, still creaked, greased em, still creaked, cleaned again, still creaked.
new setup, creaked upon 1st installation, dry only.
problem: place the left crank arm at 9 oclock, put downward pressure on it and it gives a single, loud creak. then move it to 3 oclock, give it a downward push, the creak happens again as if it just unloaded and reloaded.
-it's only caused by the left crank arm.
-the original 75s had a slight bit of wear on the inside of the press area, but nothing that seemed off-canter, buttt it did seem to leave a similar mirror-image scuff on both bottom brackets.
-i rode the original 75 crankset on the new protype bb for a few days, was quiet only for a day.
-have tried multiple crank bolts.
-have loosened and tightened the chainring bolts.
-have removed the seatpost/collar/binder bolt and greased it all.
-had the bb threads re-chased.
-checked the bb to make sure the seattube was welded all the way around before the downtube was welded on (could see some slight rippling from the inside of the bb that confirmed it).
-tried original set up with teflon tape + grease on bb threads.
-original creak was far more pronounced, could manipulate the crankarm with my hands and make it creak (with a fair amount of force), but the new setup's creak requires bodyweight.
-have done the original setup it without the pedal on the left arm (drive side pedal is stripped so it's stuck on there for now), new setup never had pedals, just body weight on the bare arm.
-both bottom brackets are iso, so they match the taper properly.
-have greased the interface where the non-DS cup slips onto the bottom bracket.
my fear, the frame is cracked.