possible chainline issue 34/32?

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djbowen99
Posts: 66
Joined: Sun Aug 16, 2015 1:46 am

by djbowen99

bike is a 2014 Roubaix running etap wifli/dura ace 9000 c24/11-32 red cassette/s works crankset 2nd gen

i noticed while riding in 34/32 the bike sounds a like it's grinding a bit. when looking at the bike in a stand in this gear combo it looks like the front ring is barely grabbing the chain as you spin the crank.

The hanger has been aligned, crankset was removed and checked to make sure it was sitting correctly. the only thing i can think of is the chainrings are off of an older set of s works (first gen) and maybe that's an issue.

anything i am overlooking? i was thinking of putting in .6mm chainring washers but i feel i shouldn't have to go this route.

stien
Posts: 17
Joined: Sat Apr 12, 2014 12:09 pm

by stien

Sram optimized Etap to work on Sram stuff. Even a Shimano chain on Sram chainrings is loud. The answer is go full Sram.

joejack951
Posts: 350
Joined: Fri Feb 18, 2005 6:50 pm
Location: Wilmington, DE

by joejack951

Something isn't right. Small/big should have a decent chainline so the chain shouldn't be looking to jump off the ring or cog. Are you sure your derailleurs are properly set (unlikely cause, but free to check)? How worn are the inner chain ring and chain? A 34T ring and chain are pretty cheap and would eliminate two of the most likely causes of your issue.

djbowen99
Posts: 66
Joined: Sun Aug 16, 2015 1:46 am

by djbowen99

thanks, derailleur is aligned well, everything is shifting perfectly fine. when looking at the bike from the rear you can see the chain is pulled over from the chainring itself. The chain was replaced a few weeks ago with a new sram chain. I have a new sram 34t on the way, hoping that will help.

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bearsdidit
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by bearsdidit

stien wrote:Sram optimized Etap to work on Sram stuff. Even a Shimano chain on Sram chainrings is loud. The answer is go full Sram.


I actually prefer my eTap group with a Shimano chain and cassette. I think the bike is much quieter with the Shimano components and there is no noticeable decrease in performance.

djbowen99
Posts: 66
Joined: Sun Aug 16, 2015 1:46 am

by djbowen99

I did realize after riding tonight that this issue is while slowly freewheeling of that makes a difference.

slick1
Posts: 211
Joined: Wed Nov 30, 2005 1:35 am

by slick1

If you're slowly freewheeling then it cant be your chainline. Your cranks aren't spinning if you are freewheeling.

The grinding might be coming from the stuffed bearings in your freehub body or wheel bearings.

Sent from my SM-G935F using Tapatalk

djbowen99
Posts: 66
Joined: Sun Aug 16, 2015 1:46 am

by djbowen99

Freewheeling was not the right word to use, I meant to say spinning the crank in reverse.

joejack951
Posts: 350
Joined: Fri Feb 18, 2005 6:50 pm
Location: Wilmington, DE

by joejack951

djbowen99 wrote:Freewheeling was not the right word to use, I meant to say spinning the crank in reverse.


Spinning the cranks in reverse with anything less than a perfect chainline is liable to cause the chain to want to derail. The simple solution is to not pedal in reverse, save for getting the pedals in the right spot to get moving from a standing start. Why else do you need to pedal backwards?

djbowen99
Posts: 66
Joined: Sun Aug 16, 2015 1:46 am

by djbowen99

I was looking at the chainline in the workstand while I was installing a new wheelset when I noticed and heard it. I don't find nudes ever pedaling backward except when clipping in.

hogehoge
Posts: 39
Joined: Mon Feb 25, 2013 11:59 pm

by hogehoge

Does the rear mech clear the 32T with a enough space? On Shimano Mid cage I have to tighten B-Screw a lot to properly clear a 32T cassette.

jobvisser
Posts: 78
Joined: Sun Aug 14, 2016 10:24 am

by jobvisser

joejack951 wrote:
djbowen99 wrote:Freewheeling was not the right word to use, I meant to say spinning the crank in reverse.

i kind of had this problem . changed my 52/36 11-25 with the old sram red 10 spd derailleur to 50/34 with 11/32 with a long cage deraileur (the one you can use with 36 teeth) and went for a 60km test ride and it was creaking as hell... turned out my chain was a bit too short so i took a brand new one and that fixed it. it might be worth inspecting your wheelbearings that could be it aswell

djbowen99
Posts: 66
Joined: Sun Aug 16, 2015 1:46 am

by djbowen99

hogehoge wrote:Does the rear mech clear the 32T with a enough space? On Shimano Mid cage I have to tighten B-Screw a lot to properly clear a 32T cassette.
it clears ok and it set to the 5mm reccomendation from sram

djbowen99
Posts: 66
Joined: Sun Aug 16, 2015 1:46 am

by djbowen99

I just realized when I removed the Ultegra groupset with medium cage derailleur I simply copied the chain length when I installed the etap. Maybe the cage lengths was different enough where I ended up with a short chain?

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