HOT: Active* forum members generally gain 5% discount at starbike.com store!
Weight Weenies
* FAQ    * Search    * Trending Topics
* Login   * Register
HOME Listings Articles FAQ Contact About




Post new topic Reply to topic  [ 3 posts ] 
Author Message
PostPosted: Thu Apr 05, 2012 1:36 am 
Offline

Joined: Wed Jun 08, 2011 1:41 am
Posts: 5
I need advice from a tech wizard. I wanted a bit stiffer big chainring than the one that came with my SRAM S950 compact crankset. Thinking that I only needed to specify 50T 110BCD I bought a Red big ring with that spec and was surprised to find that the spacing between small (34) and big ring is wider with the new Red big ring than it was between small ring and the original big ring. I didn't measure it but it had to be at least 3+ mm wider because I couldn't even come close to shifting onto the big ring with the front derailleur limit screw setting that worked perfectly with the original rings.

What I expected was that the gap between rings would be the same given that both the new and old big ring are 50T 110 BCD, and that a difference as big as I found would require a fairly large widening adjustment of the front derailleur travel which I would expect to affect the angle of chain crossover and probably create noise and wear problems.

Has anybody ever tried installing a Red big ring on a S900/950 compact crankset and found a similar difference in spacing between the two rings? Advice will be greatly appreciated.

thanks, Jeff

_________________
1993 Merckx MXL
2011 Cervelo R3
2012 Madone 6.9 SSL


Top
 Profile  
 
Posted: Thu Apr 05, 2012 1:36 am 


Top
  
 
PostPosted: Thu Apr 05, 2012 2:00 am 
Offline

Joined: Mon Aug 16, 2010 6:43 pm
Posts: 438
Location: Canada
That does not sound right... Are you sure the ring is installed correctly? You should take accurate measurements to confirm this "at least 3+mm variance"

I feel like you did something during installation to disrupt your setup.. How did you change your rings? Take the crankset off or leave it on bike? Move the derailleur at all? Etc...


Got some pics you could post of your setup?

_________________
Flickr
Tarmac SL3 Project Yellow
Follow on Instagram


Top
 Profile  
 
PostPosted: Thu Apr 05, 2012 3:34 am 
Offline

Joined: Wed Jun 08, 2011 1:41 am
Posts: 5
I'm kicking myself for not taking actual measurements of the gap between rings when I had the new Red chainring on the crankset. I thought of this only after I discovered I couldn't shift onto the new Red ring, removed it and put the old, original chainring back on the crankset. After reading your reply I did go measure the offset of the teeth of both chainrings from the back surface and found that the Red chainring appears to have a 1mm wider offset than the original ring. So much for my 3+mm estimate. ( I say "appears" because I didn't have a set of calipers and just eyeballed each on end with a metric rule)

But to answer a few questions: I installed the new Red ring onto the spider without removing the crankset from the bike. Simply lifted off the chain, removed the five bolts and swapped out the old ring, replacing it with the new ring while holding the small ring in place.

I did not make any front derailleur adjustments for the new ring; didn't think I would need to. And when I swapped the old, original big ring back onto the crankset and tightened the bolts I found that the front derailleur was again able to make perfect shifts just like before.

Anyway, now that it seems the gap is only 1mm wider with the new Red ring, I'm wondering if I shouldn't just put it back on, take confirming measurements of the gap between rings, and if it's really just 1mm, adjust the limit screw on the front derailleur to accommodate the wider offset and see what happens.

_________________
1993 Merckx MXL
2011 Cervelo R3
2012 Madone 6.9 SSL


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 3 posts ] 


Who is online

Users browsing this forum: Google [Bot], Selmer, SixThirteen and 30 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

   Similar Topics   Author   Replies   Views   Last post 
There are no new unread posts for this topic. Sram Red 110BCD bigger chainring options

in Road

Grimpeur

3

894

Thu Oct 10, 2013 10:06 pm

Grimpeur View the latest post

There are no new unread posts for this topic. 15 or 20 mm original top cap/cone for Colnago EPS - where?

in Road

klingej

0

127

Mon Feb 24, 2014 10:39 am

klingej View the latest post

There are no new unread posts for this topic. Swissstop v Campagnolo Original Pads

in Road

ultimobici

2

382

Sun May 18, 2014 4:25 pm

Geoff View the latest post

There are no new unread posts for this topic. 2014 Flite shape vs. original

in Road

ITTY

11

672

Mon Jun 30, 2014 3:16 pm

ultyguy View the latest post

This topic is locked, you cannot edit posts or make further replies. Chainring question

in Road

poppiholla

1

249

Fri Aug 01, 2014 10:49 pm

rijndael View the latest post


It is currently Thu Sep 18, 2014 12:45 pm

All times are UTC + 1 hour




Advertising   –  FAQ   –  Contact   –  Convert   –  About

© Weight Weenies 2000-2013
hosted by starbike.com


How to get rid of these ads? Just register!


Powered by phpBB