Weird Bottom Bracket Problem...OR?

[oldpotatoe]

Originally Posted by LiveFreeOrDie

So after putting together one of my bikes for the Spring, I've discovered a problem that I can't figure out how to fix.

First the problem: whenever I pedal, there is a grinding feeling in the bottom bracket. You can clearly hear and feel it. It is there with the tiniest bit of torque...while it's in the small chaining. Switch up to the large chainring, it disappears. First I thought it was bunk bottom bracket. Got a new one, problem still exists. Thought it was the pedals, replaced them with known good ones, problem still there. Finally, I thought it might be the chainring bolts. Replaced them with new ones, problem still there.

What confuses me is that the grinding disappears while in the large chainring. Go down to small one, grinding sound appears. It's quite perplexing. I'm fearing at this point it might be the frame. If that's the case, it looks like I'll be contacting the guy who sold me the frame.

I'm hoping for the best. Thanks guys!

I'll bet the small ring is worn out. Not enough to skip or anything but I have seen this many times..replace.

[rustychisel]

can small chainring be put on wrong way around, thus not having enough clearance from the large chainring?

Thus, chain will scrape on inside edge of large chainring. Examine for scuff or scratching.