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can you diagnose this problem?(7 posts)

can you diagnose this problem?esbike
Aug 13, 2002 7:52 PM
A very strange sound is coming from my bike. It only happens after a warm-up period of about 10 minutes and then only happens on hills when I'm putting pressure on the pedals. It is not the bottom bracket as I put a new one on and it still happens. It seems to becoming from the rear of the bike and persists through any combination of gears. The sound is like a rubbing which occurs with each pedal downstroke. But if I get off the bike and spin the crank it is gone. I switched out the wheel to an identical one from another bike and the sound is gone. I guess it could be coming from the spokes tensioning/detensioning, but it really sounds more like a rubbing noise than the "ping" that spokes can make. Anybody else ever have something like this happen?
I'll try..gogene
Aug 13, 2002 7:59 PM
Have you checked the bearings on your rear wheel?
re: can you diagnose this problem?Chainstay
Aug 13, 2002 8:17 PM
Are you riding Ksyriums? Some wheels have a lot of noise between the hub and the spokes. Try some WD 40 on the interface. Try flexing the rear wheel by pushing down on the crank with the brakes on and the bike leaned away from you. You should hear sounds coming from the BB and the wheel flex. This might help you isolate the sound
This happened to me........tronracer
Aug 14, 2002 4:53 AM
I didn't have the rear wheel on completely straight and there was a rubbing noise from the tire hitting the chainstay. It didn't make the noise when I spun the cranks and held the rear wheel up by the seat however. I guess under some load, stuff flexes making the tire hit the chainstay. Just make sure the rear wheel is on straight. If that's not the problem, then maybe someone else has the right answer.
tighten down the cassettemr_spin
Aug 14, 2002 7:16 AM
I once had a loose cassette that caused a strange noise on my bike. Took me months to figure it out. The cassette was loose enough so the cogs rattled around. Take off your wheel and see if there is any play in the cogs.
re: can you diagnose this problem?aliensporebomb
Aug 14, 2002 12:58 PM
Just a guess: freehub bearing?

My wife used to have a comfort bike that did a similar
thing and it was literally a week old. They just looked
at it and it didn't do it again and took it home. Then
it did it again. They swapped the rear wheel after that
but it wasn't the bike for her so it got sold with less
than 8 miles on the odometer. Geez.

It was kind of a rubbing sort of sound but it didn't
always happen.

Now she's got a recumbent and that thing makes more weird
noises than any bike I've ever seen and I can't for the
life of me figure out some of them.

The weirdest is this:
Makes a weird occasional knock sound only when she rides
it. I can ride it, no weird noise. Local bike shop guys
ride it, no weird noise. My wife rides it, an odd
occasional knocking sound that is more pronounced when
turning right. I thought it might be the chain gently
hitting something but I haven't a clue. I think it might
be possessed.
re: can you diagnose this problem?esbike
Aug 15, 2002 9:19 PM
Well as a follow-up, the problem is solved. Nobody will probably ever read this message as I am already in the "next 50". I had the wheel trued and the freehub greased and viola! problem solved. Left coast cyclery in Berkeley has great mechanics, fyi.