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Chainring warped?(4 posts)

Chainring warped?johnrossi808
Jun 6, 2001 8:15 PM
While replacing my chain, I noticed my Ultegra Chainrings are warped. I can really see it wobble when I spin the cranks. I wonder if this is the cranks, chainrings or bottom bracket that's doing this. :-(
re: Chainring warped?LC
Jun 6, 2001 8:46 PM
Because you said "rings" I would guess it is one of the spider arms. I have never seen one of the new splined BB's bend, but there is always a first.
re: Chainring warped?mackgoo
Jun 7, 2001 3:51 AM
I think there is a small amount of wave in the chain ring to assist in getting the chain on. Anyone else know for sure?
Warp speedKerry Irons
Jun 7, 2001 7:42 PM
Chainring wobble is very common, most typically caused by a spider arm getting "tonked" somewhere along the way. The wobble is NOT there to assist shifting - that is done with pins, tooth shapes, and ramps. This can be fixed by supporting the BB (set the left crank - at the BB - on a block of wood) and tapping the bent spider with a hammer/wood block to get it back in the same plane as the rest. Go slow, and you can correct the wobble. Recognize that pedaling force can make the rings seem to wobble even when they are flat, so check for wobble without any load.