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I have a Motobecane 700HT with a stock drivetrain. it's got about 1000 miles on it (almost entirely road/rollers, unfortunately). Last night while I was riding, I noticed a strange click/pop coming from what sounded like the left side of the bottom bracket while pushing down. It happened when my foot was at about the 8 o'clock position in the stroke. I don't have lots of bike-specific tools to tear things apart but I"m willing to buy some and start learning... What could be wrong? What should I look for?

Extra info... it only happens when the left pedal is under power. Backpedaling is nice and quiet. Spinning slower than the rear wheel is spinning (so the chain isn't tensioned) is also nice and quiet.

Thanks for the info...
 

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Can't offer you any real advice, Simoriah, but let me share with you my experience. I went through three bottom brackets when my bike was still under a warranty, i.e., during the first 6 months! For no apparent reason, they all were quickly devloping the same or similar problem: cracking, grinding, and other noises. The last one, which I've been using now for 2 years, is no different. I just try to ignore it; sometimes it gets better, sometimes it can be real bad, but even then it doesn't seem to have any impact on pedalling.

That's perhaps not the approach your bike mechanic would recommend, but sometimes I lay the bike on the ground on one side and pour some chain lube where the spindle goes into the BB; I leave it like that for a day or two (may repeat this procedure on the other side as well). It's a poor man's fix, but it makes the pedals rotate smoother. As far as I know, most BBs aren't repeareable -- you can't even disassemble them -- so I have nothing to lose, so to speak. I figured that I'd replace it when it dies on me completely.
 

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I had the same problem with my lx cranks. Creaking, poping, really annoying. It only seemed to do it when i cranked down. I had quite alot of miles on them so i decided to take them apart, bottom bracket and all. When i did i noticed that the grease that i had put on there was gone. I regreased the bottom bracket and cranks really good. Silent as a ghost! Maybe it was to much metal to metal. Make sure that your cup that holds the bracket in place is not cracked. Happened to a buddy of mine. The es-51 bottom bracket for the lx cranks has a plastic cup that holds the bracket in place. Made the same noise. Just my two cents.
 
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