Cyclocross - Bottom bracket knocking
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Lately I've noticed a sort of knocking sound coming from (I think) the bottom bracket of my '04 Axis when pedaling in higher gears w/ higher resistance. I hear it on every down stroke of my right foot. I know it's impossible to speculate, but does this sound like a bracket issue or maybe a pedal or crankset problem?
04-11-05, 01:14 PM
Stupid question. I had this same problem on my SS CX. Only on the downstroke. It was my seat...
First check to make sure your seat, seat post, and pedals are on nice and tight. Do you notice the knock when you are seated AND standing?
04-11-05, 03:44 PM
Awesome avatar BTW. Sounds like that can be hard to track down. Try grabbing your crank and rocking it side to side (push and pull on it near the pedal from the side). Is there play? Now check your pedals the same way, do they have a lot of play. Try your rear wheel as well. Push it from side to side and check for knocking. There should not be any. Check that your chainring bolts are all tight.
Does it happen when you are seated and standing, or just one?
04-12-05, 06:11 PM
Usually a knocking - as oposed to a creaking - sound is due to a very loose BB. And you should be able to feel it as well.
04-13-05, 04:52 AM
Just one side suggests a loose crank bolt perhaps. Flibble everything. Tighten it up if it moves. Also, check your chainring teeth: one bent or burred tooth could produce a clonk of this period.
04-21-05, 01:31 PM
as stated by others, check everything...I assume you've done that and you still think it's from your bb. how old is your bb? assuming that you have a sealed system, there is not much you can do to the bearing and the only adjustment you have is with the cups. I find that using teflon tape on the cups will solve the problem. start the cups into the shell half way, then put some tape on the cups.
04-21-05, 02:33 PM
noises always sound like they come from the bottom bracket. could be loose cranks, could be the bb, might also be spoke tension.
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