Bicycle Mechanics - Bottom Bracket Vibration?
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06-10-09, 10:29 AM
I just built my first fixed gear bike. I want to make sure everything is working perfectly on it. However, I noticed that when I pedal quickly or climb up hills, the bottom bracket feels like it's vibrating. When going a constant speed, it feels fine.
Could I have just overtightened the BB? Any other causes? I will be taking it out and experimenting later today.
Here's my bike, btw: http://velospace.org/node/20796
Nice looking bike!
Crankset and Bottom bracket:
Sugino Messenger (165mm) and IRD QB-75 (103mm)
What type of BB? Loose balls? If so it does sound like it's overtightened.
06-10-09, 02:09 PM
It's a sealed cartridge...so no.
06-11-09, 02:33 PM
06-11-09, 02:49 PM
could it just be because the crank arms are lopsided? they don't seem to run very smoothly...
06-11-09, 04:01 PM
continuing to talk to myself...
i just reinstalled the bottom bracket and crank arms. but the chain ring still isn't turning around straight...do i have a bent chain ring? i bought it new. it's a sugino messenger crankset.
Without the crankset mounted, does the axle wobble as you turn it? Did you face the hanger tube, or check for square?
06-11-09, 05:47 PM
Worn chain and/or chainrings can cause this.
06-12-09, 03:05 PM
went to the lbs and this was the diagnosis:
1. lockring not tight enough (this is a fixie)
2. chainring bolts may not have been tight enough
3. chainring is warped
so, all of those three things combined were giving me problems. my crankset is new, so this is unfortunate.
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