Bicycle Mechanics - Busted bottom bracket/bearings?

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Buglady
05-23-07, 03:45 PM
Hi all,
Possibly stupid question: I am getting a recurring "clunk" and the feeling that there is too much play in my pedals (on clunk per pedal revolution, and a feeling that there's some side-to-side flex, although when I grab the pedal and wiggle it, it doesn't seem to move). I have had the bottom bracket tightened, which stopped the noise briefly, but now it is back and is accompanied by a buzzy rattle that seems to be resonating through the frame and front fork. Could the bracket or the bearings be going? My LBSs don't seem to be much help - one told me my cassette was worn out, one tightened the bracket, and a third denied hearing any noise at all.

(The bike had a full tune up last month that also temporarily stopped the rattle/clunk/whatever.)

Bike is a 2006 Norco Pinnacle, very basic but I was really wanting to get more out of it than this. It has maybe 500kms on it altogether. It is my commuting vehicle.

Thanks!

operator
05-23-07, 03:56 PM
Buy $5 set of plastic platform pedals, swap and test. Noises and creaks can come from anywhere on the bike. Only an exhaustive test, one by one can solve it.
neil0502
05-23-07, 03:57 PM
Here's a good place to start the diagnostic process: http://sheldonbrown.com/creaks.html

vpiuva
05-23-07, 06:18 PM
I didn't have the clunk but did have a wierd buzzy noise throughout the frame -- turned out my (aluminum) water bottle cages were rubbing each other.
tellyho
05-23-07, 07:59 PM
These noises are the worst. There are many threads on clunk-chasing around, but basically you need to eliminate all of the easy sources: seat, seatpost binder, bottle cages, cable housing slap, stem, handlebar, front derailleur, wheel not centered, QR skewer loose. From there, you move on to the tougher ones: pedals, crankarms, cassette / rear hub, bottom bracket. And I'm probably forgetting a lot. Lube everything up and tighten up and see what you get.

That said, if you had to have the BB tightened, then my money would be on that, especially if it solved the noise problem to begin with. A new one is $25 plus installation.