Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 05-30-03, 09:29 PM   #1
budbuster69
Member
Thread Starter
 
Join Date: May 2003
Location: Edmonton, Alberta, Canada
Bikes:
Posts: 48
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Rear Derailleurs (Long cage & Short)

whats the difference between the long cages of derailleurs and short cages?
budbuster69 is offline   Reply With Quote
Old 05-30-03, 10:18 PM   #2
NZLcyclist
MaNiC!
 
NZLcyclist's Avatar
 
Join Date: Feb 2003
Location: Hamilton, New Zealand
Bikes: 2004 Cervelo Soloist 105, 2005 Apollo Apex, 2006 SCOTT Speedster S30
Posts: 1,600
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
The longer the cage, the larger the sprocket you can put on the rear.

A 32T gear will need a longer cage to accommodate the extra chain length needed than a 25T.

Brendon
NZLcyclist is offline   Reply With Quote
Old 05-31-03, 07:08 AM   #3
Spoke Wrench
Senior Member
 
Join Date: Apr 2003
Location: St Louis, Missouri
Bikes:
Posts: 91
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Rear derailleurs have two separate, but related, range issues.

The first is largest cog capability. It is determined by the positioning of the upper pulley relative to the cassette cogs and has nothing to do with arm length. As you install progressively larger cassette cogs, eventually the upper pulley will rub against the largest ones. Mountain bike derailleurs have the capability to handle larger cogs than road bike derailleurs.

The second is chain slack take up. It takes more chain to wrap around the big/big sprocket combination than it does for the little/little combination. The rear derailleur has to account for that difference. Long arm rear derailleurs have the capacity to take up more chain slack than short arm derailleurs.

Shimano mountain bike derailleurs come in different arm lengths. They will all handle a 34 tooth rear cog, but some will wrap up more chain slack than others.
Spoke Wrench is offline   Reply With Quote
Old 05-31-03, 07:37 AM   #4
mike
Senior Member
 
mike's Avatar
 
Join Date: Jul 2000
Location: Snowy midwest
Bikes:
Posts: 5,392
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
An even more simple answer:

Long "cages" are usually used for bikes with triple front chainrings.

shorter "cages" are most often found on road bikes with only double chainrings.
mike is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 09:03 AM.