Chain rings warped?

[I_paint]

I just got my new (slightly used) bike, a 2006 cervelo soloist team. According to the shop the previous owner traded it in for something else. Personally, I love this bike. But after riding it awhile ive noticed a few issues, most are pretty typical of what happens to a new bike when you start riding it, cable stretch, deraileurs needing adjustment etc.

I've noticed that the chain rings are slightly warped, which causes some rubbing on the front deraileur in cadence with my pedal strok in some gears. To go along with that theres a slight clicking sound coming from down in the drivetrain/BB (very difficult to tell where this sound is coming from), again this is in cadence with my pedal stroke, and it is distinct from the chain rubbing on the derailleur. These problems are probably are related. My theory is that the warped chain rings were caused by the previous owner mashing up a hill cross-chained or something.

The other possibility is that its a BB problem, which I don't think it is.

What do you guys reccomend doing about this? And is it ok to ride it much before fixing it?

 

[capwater]

Warped rings sound weird. I'd check the BB first. Check it out when its not under load, is there any difference?

 

[John M]

I just got my new (slightly used) bike, a 2006 cervelo soloist team. According to the shop the previous owner traded it in for something else. Personally, I love this bike. But after riding it awhile ive noticed a few issues, most are pretty typical of what happens to a new bike when you start riding it, cable stretch, deraileurs needing adjustment etc.

I've noticed that the chain rings are slightly warped, which causes some rubbing on the front deraileur in cadence with my pedal strok in some gears. To go along with that theres a slight clicking sound coming from down in the drivetrain/BB (very difficult to tell where this sound is coming from), again this is in cadence with my pedal stroke, and it is distinct from the chain rubbing on the derailleur. These problems are probably are related. My theory is that the warped chain rings were caused by the previous owner mashing up a hill cross-chained or something.

The other possibility is that its a BB problem, which I don't think it is.

What do you guys reccomend doing about this? And is it ok to ride it much before fixing it?

I agree with capwater. Chainrings should not warp under even harsh riding conditions unless the bike falls onto the large chainring or bash it into a rock or curb. If both large and small chainrings appear to be warped in the same spot, then it is likely the BB.

Are you sure that you are not just experiencing normal drivetrain flex by which the chain contacts the outer FD cage under heavy load during the downstroke? This can normally occur and is dealt with by making sure the FD is properly adjusted and then trimming the FD out a little while riding.

 

[artmichalek]

Both the clicking and appearance of a warped chain ring could be caused by unevenly tightened chain ring bolts.

 

[capwater]

Both the clicking and appearance of a warped chain ring could be caused by unevenly tightened chain ring bolts.

Good advice on that call. There will also be some frame flex depending on what you are doing when you observe the so-called warping. You'd be surprised how much a frame flexes during a sprint.

 

[I_paint]

Warped rings sound weird. I'd check the BB first. Check it out when its not under load, is there any difference?

I dont notice clicking when its not under load, it seems to happen when I'm pedalling harder, and more in certain gears. I really notice it when i accelerate in a sprint. But I don't feel anything through the pedals.

I agree with capwater. Chainrings should not warp under even harsh riding conditions unless the bike falls onto the large chainring or bash it into a rock or curb. If both large and small chainrings appear to be warped in the same spot, then it is likely the BB.

Are you sure that you are not just experiencing normal drivetrain flex by which the chain contacts the outer FD cage under heavy load during the downstroke? This can normally occur and is dealt with by making sure the FD is properly adjusted and then trimming the FD out a little while riding.

Im pretty sure its not normal flex when I can suspend the rear wheel in the air, turn the cranks and watch the chain rings wobble a few millimeters as the chain moves side to side in the FD.

Both the clicking and appearance of a warped chain ring could be caused by unevenly tightened chain ring bolts.

Thanks, this is something I can check out without too much trouble, but to really get them even I'd need a torque wrench of some sort.

Thanks all!

 

[artmichalek]

Thanks, this is something I can check out without too much trouble, but to really get them even I'd need a torque wrench of some sort.

It's like putting a wheel on a car. Get all five bolts finger tight, then work your way around in a star pattern with an allen wrench. Go around a few laps tightening each bolt a little bit each time. You can use a torque wrench and still warp the ring if you go around in a circle.

 

[I_paint]

It's like putting a wheel on a car. Get all five bolts finger tight, then work your way around in a star pattern with an allen wrench. Go around a few laps tightening each bolt a little bit each time. You can use a torque wrench and still warp the ring if you go around in a circle.

Thanks for the tip! I'll try this out tonight and go for a ride if it ever stops raining and the roads dry out. If not, looks like I'll be running in the rain. I guess I'm one of those people that can't stand getting my bike even a little dirty.

 

[alfeng]

The other possibility is that its a BB problem, which I don't think it is.

As soon as possible, check to see if the crank, itself, isn't slightly loose on the BB's spindle ...

If it is loose, tighten it (probably uses an 8mm Allen wrench unless you have a mega-type crank) AND hope that no damage has been done to the mating surfaces.

 

[capwater]

I dont notice clicking when its not under load, it seems to happen when I'm pedalling harder, and more in certain gears. I really notice it when i accelerate in a sprint. But I don't feel anything through the pedals.
!

Check the so-called warpage when not under load and let us know. If there is no warping affect it ain't the rings. Crank arms, chain ring and BB should all be checked for tightness.

 

[hd reynolds]

Check BB for looseness by pressing alternately inwards on each pedal arms. It could be one of the cups have come loose.