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  [ 7 posts ] 
Author Message
PostPosted: Mon Jul 30, 2012 2:57 pm 
Offline

Joined: Tue Jan 13, 2009 3:30 pm
Posts: 37
Location: Mountain View, CA
I have made the decision to switch from a standard crankset (53/39) to a compact (50/34). I am currently running all Dura Ace 7900. I just ordered a new FC-7950 crankset. What will be involved in making the switch? Is this just a matter of swapping out the cranks? Or will the 50T chainring require that I lower the front derailleur to maintain proper tolerances? Also, will I need to shorten the chain with this change? Thanks!


Top
 Profile  
 
Posted: Mon Jul 30, 2012 2:57 pm 


Top
  
 
PostPosted: Mon Jul 30, 2012 2:58 pm 
Offline
User avatar

Joined: Fri Feb 11, 2011 3:04 am
Posts: 2360
Location: Mississippi
Yes and yes. Lower derailleur and shorten chain.....

_________________
Cervelo R3

http://weightweenies.starbike.com/forum/viewtopic.php?f=10&t=125962


Top
 Profile  
 
PostPosted: Mon Jul 30, 2012 3:19 pm 
Offline
User avatar

Joined: Wed Jan 19, 2011 11:14 am
Posts: 1200
But.....
You if ou want it too shift well you need to set the cage to big ring gap towards the upper limit not the lower limit like you would with a std chain set.

Basically It needs a little more room to get the chain up nice and fast. Between 2-3mm works pretty good in my experience

_________________
project black


Top
 Profile  
 
PostPosted: Tue Jul 31, 2012 11:10 am 
Offline

Joined: Mon Oct 12, 2009 6:36 pm
Posts: 246
No need to shorten the chain. I switch between compact and regular crankset 2-3 times a year, never changed the chain length and never had any problems.


Top
 Profile  
 
PostPosted: Tue Jul 31, 2012 12:42 pm 
Offline
in the industry

Joined: Sat May 12, 2012 7:25 pm
Posts: 1329
Location: Glermsford, Suffolk U.K
I think the above will be true if your cassette is of narrow range. The wider the range of the cassette the more likely you will encounter chain length issues.

_________________
www.thecycleclinic.co.uk


Top
 Profile  
 
PostPosted: Tue Jul 31, 2012 3:18 pm 
Offline

Joined: Tue Jan 13, 2009 3:30 pm
Posts: 37
Location: Mountain View, CA
I'm running an 11-28 cassette. It would certainly be nice to be able to easily switch between compact and standard. I guess I'll just wait and see how things look as I do the install.


Top
 Profile  
 
PostPosted: Tue Jul 31, 2012 5:45 pm 
Offline

Joined: Thu Jun 09, 2011 4:10 pm
Posts: 280
there's two schools of thought for optimal chain length:

1) minimum length: You wrap big-big, and then add 2 lengths. This gets you the lightest weight. However, to switch gearing, you end up needing a new chain if you need more links, since piecing together links of a chain with different amounts of wear can cause issues.

2) maximum length: You go small-small, and thread it through the derailleurs, then subtract the least amount of lengths to get to a length the derailleur can handle. This sacrifices some weight, but allows the greatest amount of adjustability in gearing. It probably makes your chain last slightly longer since the wear is distributed across more links.

Personally, I tinker with my gearing a reasonable amount, so I go for maximum length at the expense of 10-15 grams.


Top
 Profile  
 
Posted: Tue Jul 31, 2012 5:45 pm 


Top
  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 7 posts ] 


Who is online

Users browsing this forum: Baidu [Spider], BdaGhisallo, Google [Bot], nathanong87, Ohnooo, SLCBrandon and 44 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. Colnago C59: Switching Headsets

in Road

SGcyclist

1

301

Wed Apr 23, 2014 2:40 am

willy View the latest post

There are no new unread posts for this topic. Dura-ace 9000: Problem switching to smallest cog-wheel

in Road

luminous

11

770

Wed Apr 02, 2014 3:33 am

afalts View the latest post

There are no new unread posts for this topic. Enve Compact Flex

[ Go to page: 1, 2 ]

in Road

KWalker

20

1998

Mon Jan 27, 2014 4:34 pm

Briscoelab View the latest post

There are no new unread posts for this topic. Alignment of FSA Compact Bars

in Road

Valbrona

5

731

Mon Nov 18, 2013 2:28 pm

Devon View the latest post

There are no new unread posts for this topic. Best Oversized Compact chainrings

in Road

prebsy

11

969

Sun Jan 19, 2014 2:25 pm

jmartpr View the latest post


It is currently Thu Sep 18, 2014 3:16 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