# Chain Rub on the Large Ring



## Midwest Playa (Sep 12, 2008)

I just got my 09 Cannondale Supersix from the shop after installing a new warranty replacement crank arm on the chainring side. My Dilema is when I got the bike back, I noticed that the chain would rub in the inner large ring when the rear cassette is on the smallest gear and will not clear the rub until I shift it to the 3rd gear from the smallest. I took it to another Cannondale dealer here and after speaking with the mechanic he stated he could not correct the problem. I did not have this issue before can someone give me their input so I can tell my LBS what to do. He said he tried adding shims and it did not make a difference. I am running the 53/39 gears. Sram Red components. I know that its not recommended to ride the gears that way but I still think it should not rub.

Please help he said he was going to have the Cannondale Rep look at it.


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## CHL (Jun 24, 2005)

MP:

You're riding in a cross gear. Put your bike in that gear and observe the trajectory and where the rub occurs on the large chainring. It maybe simple physics and the tech could be right on the matter. Are you using the Hollowgram SL or the SRAM Red crankset?

CHL


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## Midwest Playa (Sep 12, 2008)

CHL said:


> MP:
> 
> You're riding in a cross gear. Put your bike in that gear and observe the trajectory and where the rub occurs on the large chainring. It maybe simple physics and the tech could be right on the matter. Are you using the Hollowgram SL or the SRAM Red crankset?
> 
> CHL



Thanks alot for the response I am riding the original hollowgram sl. Its frustratingg me why my local mechanic cannot correct a simple problem, I can tolerate maybe a little rubbing if I am on the smallest gear but for me to have to shift all the way to the third gear just so it wont rub I just dont think its acceptable.:mad2: 

DG if you read this can you give me your input?

Thanks again


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## Dan Gerous (Mar 28, 2005)

IMO, a 2x10 transmission is designed so the whole cassette can be used when on the big ring but not in the small ring (that's why the trim feature of most drivetrain is on the big ring, not the small). Small-small gear combos are the worst, less chain tension, rub as you can see... I think it's normal on many setups.

My question is, why are you in those gears? I would shift on the big ring before I ever get to the 4 smallest cogs.


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## Midwest Playa (Sep 12, 2008)

Dan Gerous said:


> IMO, a 2x10 transmission is designed so the whole cassette can be used when on the big ring but not in the small ring (that's why the trim feature of most drivetrain is on the big ring, not the small). Small-small gear combos are the worst, less chain tension, rub as you can see... I think it's normal on many setups.
> 
> My question is, why are you in those gears? I would shift on the big ring before I ever get to the 4 smallest cogs.



Thanks DG 

I knew you would be watching the threads lols Actually no I dont ride in that gear configuration, I dont ride in the configuration anyways. Its just irritating that it would rub like that because it did not do that when I first got the bike. Anyways I can actually live with it, I am just anal I guess.

Thanks Again


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## CHL (Jun 24, 2005)

Hi MP:

You're not going to like this but I fear it is quite normal. I cleaned my Super Six as well as my girlfriends' today. Both do the same thing. The rub is probably not as great as yours but it could be the design of the chainrings. Both of us currently use Specialites TA Hegoa chainrings. Both sets have several thousand miles on them.

I'm surprised that this actually occurs though because the chain hits outer cage plate of the front derailleur. I actually have to slightly move the front derailleur to allow the chain to hit the large chainring. Although, I use DA7800 and not SRAM Red. Could be a design difference between the two brands.

CHL


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## Devastator (May 11, 2009)

The description you gave makes it unclear to me which combo is rubbing, 53-12 or 11 or 39-12 or 11. But on my Super I get rub on my 53-11, my chainring is bent slightly, I get more run the more power I apply. If the problem is in the 39 and smallest, then it isnt even a gear you should be in, as you can get similar or the same ratio in the 53. I use to have this expectation that my bike should work well having fairly decent stuff, kinda pissed me off and now if it kinda works, Im satisfied. 

I have 53/39 Mark V Cannondale rings with Sram Force 11-25 cassette and Sram 1080R chain.


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## strathconaman (Jul 3, 2003)

You are lucky. My bike doesn't give me any warning when I am cross-geared.


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## Midwest Playa (Sep 12, 2008)

Thanks for all the input Gentlemen I gues its one of the few things we all have to compramise, I feel a little better knowing that I am not the only one whos been faced w this dilema.LOLS

Thanks Again. I will pick up my bike on Teusday and just ride the Crap out of it if this weather over here in the Midwest gets a little better.Dont know about you guys but its been a very cold winter this year.

Midwest Playa


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## zamboni (Sep 11, 2003)

John,

Can you do the trim on Sram Red FD when you in that gear combo? I don't have this problem with my setup.


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## Midwest Playa (Sep 12, 2008)

zamboni said:


> John,
> 
> Can you do the trim on Sram Red FD when you in that gear combo? I don't have this problem with my setup.


Thanks Zamboni not sure what you are asking me but I will ask my Cannondale Tech over here

Thanks:thumbsup:


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## johno1 (Oct 26, 2005)

It sure seems to me that the problem is in the new crank arm install. As unlikely it may seem, the chainrings have been moved inboard, changing the chain line and resulting in the rubbing you describe. The fact that this issue did not exist until the crank arm installation work was done means that's when something happened causing the problem. IMO, even though small/small is not recommended, it should still work. Unfortunatly, this is not an uncommon problem.


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