I upgraded a full groupset, including the crankset on my Trek Madone. My particular Madone uses Trek's press-fit BB-90 internal bottom bracket. I probably had 15,000 miles on the BB when I changed out the crankset. I've got about 1,000 miles on the new crankset and I'm hearing (and feeling) a deep "popping" or "knocking" sound coming from the BB/crank area, which has started within the last few hundred miles.
Here's what I've tried so far to try and isolate it:
-Remove and replace pedals
-Inspect and tighten rear QR
-Lube spoke crossover points in rear wheel
-Check torque spec and lube chainring bolts and crankarm bolts
-Check BB press fit for looseness by wiggling crankarms
-Clean and repack BB bearings with grease
-Inspect BB shell in bike for wear/cracks/looseness
-Regrease Hollowtech II BB spindle, and splines where left crankarm attaches
-Inspect crankset
-Re-install old crankset
None of this has done anything to help. It happens most frequently under load, and *seems* to occur more on the small chainring/larger cogs combo (though not just one gear). Since it does happen (less frequently) in the big ring, I can't see how it could be a chainring bolt issue. Like I said, I tried re-installing the old crankset, and it still seemed to happen, but not as much, so I am guessing this eliminates anything to do with the new crankset itself.
Here's my theory, tell me how much I'm an idiot if necessary
I wonder if, through 15k miles on one BB/crankset combo, that these parts wore evenly. Perhaps now there is *the slightest* discrepancy in the diameter of the bearing races and the new BB spindle, which is "popping" as I put load on the crank and the parts slip within the BB shell. The next thing I want to try is to replace the BB90 (not very costly), but I don't know if that would void the Trek warranty. I don't want this to be a cracked frame issue that's just now starting, which could get worse (if it is, and I void the warranty, I'm SOL). It's a white bike, so I can use a flashlight to illuminate the frame, and I don't see any hairline cracks. But obviously I'm not an expert at this, I may not be able to see, or determine what cracks could mean what.
Is it worth a try to replace the BB90 with the new crankset, or could it be something else? Thanks!!