I have a 1988 Trek 660 I have owned since new. Two years ago, I replaced the rear hub, cassette and bottom bracket after they all went bad within 6 weeks of each other. Ever since then, I have had a very intermittent skip ( it only happens about once every 40-50 miles or so). It happens sometimes under load, sometimes not. It seems to come from the bottom bracket area. The Trek mechanic can't duplicate it. Any suggestions?
Thanks, Joel
try to explain "skip" a little better. do you mean pedal stroke with no forward power?
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Dead/dying chain?
Check the chain for wear using the method Alex has on this site. If that's not it, then check chainrings and the crank interface (could be worn).
Do you ride in one gear most of the time? that's more likely to cause the skip, as the old chain bedded into the dead cassette, so the chain doesn't fully mesh with the new cassette properly. That's all I can think of.
No, I change gears frequently and I just replaced the chain last week & only have one ride on it. It still did it, so I am going to replace the cog on the rear. Suggestions?
Hmm, not sure.
Maybe try increasing the cable tension by 1/4-1/2 of a turn from either adjuster (turn anticlockwise). If that makes it worse, undo what you did and then loosen it 1/4-1/2 a turn.
it sounds like your cassette or freewheel is slipping
There are two kinds of people in the world, "Those who help themselves to people, and those who help people!"