jasonp

I just bought a new C'Dale Synapse. The first time I went out for a ride, the chain was rubbing against the FD making a constant noise (on the large cog). When I shifted to the smaller Cogs, it was making the same noise but slightly less. I called my LBS and they said for me to bring it in. When I did, the guy put it up the rack, and did some adjustments. Well to make a long story short, He eliminated the noise from the large cog but the chain still rubbed (worse so) on the smaller cogs. His response, "well thats about as good as you're gonna get it. You just can't eliminate all the chain rub." I've had a Specialized Stumpjumper for about 7 years and never had this problem. I just wanted to know from all you roadies is this really the case or does the guy just not know what he's doing. The noise really drives me nuts. Any help would be appreciated....Jason

powers2b

1. get a new mechanic.
2. read park tool website on DR adjustment.
3. lube your cables.
4. don't cross-chain

Al1943

Check my response to your message at the road bike forum.

tomacropod

the parktool article on front derailleur adjustment is top-notch as Che has observed. I strongly recommend reading it at www.parktool.com . But your mechanic is partially correct, on modern road drivetrains it is often impossible to dial out all the chain rub in all the gear combinations.

This doesn't matter though, because you shouldn't be using the larger sprockets in the large chainring. There is really no requirement for the front derailleur to be wide enough to accomodate that range of chain angles, and if the derailleur was that wide, shifting would suffer and you would be dropping chains all the time!

- Joel

ranger5oh

dYou cant completely get rid of the noise when its cross chained.... its just a fact of the matter. Switch to a different gear if it makes too much noise, its usually a very good sign its cross chained.

James_Kim2

1. do NOT cross chain
2. make sure your FD is parallel to your charing/bashguard, ect
(and make sure your FD clamp is securely tightend in correct position)
3. make sure your shifters aren't malfunctioning
4. lube your cables

word of advise, get a mechanic who has taken the full courses.

-James

jasonp

Thanks guys for all the replies. I'm gonna let them do some tweeking and see what happens.
Thanks,
JP

VegasCyclist

wow, that's a pretty unacceptable response from a LBS... you might want to check out some new shops.

tomacropod

but it's true - you often can't eliminate all the chain rub. At least they didn't try to sell him a new FD.

- Joel

superslomo

I ride a triple, and there are middle ring situations where I need to shift by a click further towards the small ring to keep the rubbing down when using a big cog at the back. You could try adjusting for it slightly while riding.

VegasCyclist

It can be true for a triple front crank, but even then 99% can be eliminated by good adjustment (enough so that you can't really hear it on the road). It is untrue for a double crank....