Wild grouppo set up. please help me.

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ihs0yz
Posts: 105
Joined: Thu Oct 16, 2014 6:33 am

by ihs0yz

I need help! Currently I have a pretty wild setup:

Campy Athena FD, Shifters, RD
KMC X11L Chain
SRAM Red GXP compact crankset
Praxis 50/34 rings

I've been trying to get the front shifting right but my chain is constantly falling in BETWEEN my chainrings when I shift down?

by Weenie


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davidalone
Posts: 622
Joined: Fri Feb 10, 2012 4:27 pm

by davidalone

your front derailleur probably isn't setup properly.

mattr
Posts: 4671
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

Or you haven't fitted the rings properly.

ihs0yz
Posts: 105
Joined: Thu Oct 16, 2014 6:33 am

by ihs0yz

Genuinely curious, how does bad shifter setup relate to chain falling in between the chainrings?

Also, I had a look around online to find out if I might have had the inner chainring the other way round but I couldn't find formal mounting guide docs on the newer design. Are the words on the smaller ring suppose to face the frame?

My LBS mentioned he reinstalled my rings once because he was curious why the catch pin wasn't aligned with the crank arm, which really doesn't happen with the new SRAM crankset. Now I'm wondering if he got it wrong.

Thanks also for the mods for setting this up as a thread, I thought I could just ask in the older SRAM Red crankset thread.. :beerchug:

aaric
Posts: 430
Joined: Thu Jun 09, 2011 4:10 pm

by aaric

Praxis published a definitive guide:

"THE GEARING MARKS MUST ALWAYS FACE THE FRAME AND ALIGN WITH THE CRANK ARM"

https://praxiscycles.com/wp-content/upl ... TB-001.pdf

RussellS
Posts: 916
Joined: Wed Feb 03, 2010 1:31 am

by RussellS

Not sure this is any help, but... Is your crankset for 11 speed? Guessing a 10 speed crankset may have more space between the rings. The thickness of the spider may be thicker than with an 11 speed crankset. Thus allowing your skinny 11 speed chain to fall between the rings. Also you may have one chainring mounted backwards. Guessing the rings do not have the teeth exactly down the middle of the ring. The teeth are offset to one direction or another. You may have the rings mounted so the offset of both rings is opposite each other thus creating too much space between the rings. Flip one or both of the rings around.

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bikerjulio
Posts: 1900
Joined: Fri Dec 11, 2009 10:38 pm
Location: Welland, Ontario

by bikerjulio

I've never seen any evidence that the chainrings in a properly assembled setup are any closer going from a 10 to an 11-speed crankset. It's not that. Myself and many others have 10-speed cranks running 11-speed drivetrains.

Nor have I ever had the chain falling between rings - don't think it's possible actually.

I can only think your rings are wrong.
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

http://www.youtube.com/watch?v=GekiIMh4ZkM

grover
Posts: 1302
Joined: Mon Jul 26, 2004 1:06 pm

by grover

From memory the PW little ring does have the teeth offset to one side. If this was installed incorrectly it would make the gap between rings bigger. Againfrom memory, the little ring should have the writing facing the frame. Also, the little ring probably has countersunk chainring bolt holes, these should obviously be facing towards the frame to allow the chainring bolts to sit in them.

I also thought maybe you have a 10 speed crankset/spider which is minimally thicker than an 11 speed spider giving room for the 11 speed chain to drop between. I recall, but am not definite, in thinking KMC 11 speed chains were every so slightly narrower which may further aggravate the issue.

If you have the new Red crank with hidden bolt then you're right that the catch pin won't line up with the crankarm. I'd place it opposite the crank arm so that at least the timing of your shift is correct with high and low load periods of the pedal stroke. Obviously the little ring has a mark that should be aligned with the catch pin as well.

Final thought. If you have the new Red crank with hidden bolt it is designed with thickness of the Red big ring mind. The big ring pushes against the flat area of the crankarm with a spacer between big and little rings. If the PW big ring is thinner than the Red ring then it will be pushed away from the frame (toward crankarm) at the hidden bolt area meaning it doesn't run true. Not sure how that will result in chain falling between rings but worth investigating.

bikedoc
Posts: 638
Joined: Thu Aug 16, 2007 3:16 pm

by bikedoc

I've seen a couple of cases where the smaller ring has not been made quite right causing this problem, both times praxis has swapped the ring and the problem was solved.

ihs0yz
Posts: 105
Joined: Thu Oct 16, 2014 6:33 am

by ihs0yz

Just to conclude the issue, it's a silly one too. My inner ring was facing the wrong way after all, I had the words facing out instead of towards the frame the way it should've been.
I could've sworn I mounted it that way because the package had instructions, I'm really not that dumb, promise :lol:

The LBS did say he was wondering why the steel pin wasn't behind the crank arm so he took it apart in the beginning, so that should be why... :wink:

Thanks by the way everyone for your time!

kode54
Posts: 3740
Joined: Tue May 23, 2006 9:39 pm

by kode54

mattr wrote:Or you haven't fitted the rings properly.


^ most likely this. make sure the chain rings are fitted in the correct direction. indentation for the chain ring bolt is obvious. if incorrectly fitted, the space in-between the chanrings are farther apart. flip it if need be.
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ihs0yz
Posts: 105
Joined: Thu Oct 16, 2014 6:33 am

by ihs0yz

I got the inner ring flipped around and it solved the problem indeed, silly mistake!

by Weenie


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