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


Go Back   > >

Recreational Cyclocross and Gravelbiking This has to be the most physically intense sport ever invented. It's high speed bicycle racing on a short off road course or riding the off pavement rides on gravel like :The Dirty Kanza". We also have a dedicated Racing forum for the Cyclocross Hard Core Racers.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 09-10-08, 11:43 AM   #1
adamt
Senior Member
Thread Starter
 
adamt's Avatar
 
Join Date: Aug 2008
Location: Portland, OR
Bikes:
Posts: 427
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
cyclocross rear derailleur

Sorry to be a pest all.

I have a question regarding rear derailleurs. I see some people going for mtn bike sets while others use road sets.

It would seem to me running an XT rear would be better than an Ultegra set up.

Is there a reason NOT to go with the mountain rear derailleur?

An XT long cage would seem to be a good set up for a 12-25, with a 44/34 up frant no?
adamt is offline   Reply With Quote
Old 09-10-08, 12:06 PM   #2
jollyGreenGiant
Senior Member
 
Join Date: May 2007
Location: Bradford Massachusetts
Bikes: C'Dale - R1000, XR7, Rize3, F600 and a couple others...
Posts: 62
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I would prefer a long cage RD in case I wanted to throw on a larger cassette for flexibility sake and nothing else. If you weren't going to use a larger cassette and knew that a road style RD was fine for your drivetrain, then shifting will typically be more accurate and faster with the short cage.

Also, I would think the XT is perhaps a little more robust than an equivalent road ( Ultegra ) one but that's probably just opinion as I've never had the best longevity with my XT RD's, then again they get abused more than my road Ultegra's!
jollyGreenGiant is offline   Reply With Quote
Old 09-10-08, 12:08 PM   #3
bluenote157
Senior Member
 
bluenote157's Avatar
 
Join Date: Apr 2006
Location: Orange County CA
Bikes: Surly CC, Raleigh Team Pro, Specialized Rockhopper with an xtracycle
Posts: 960
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
haha.. i raised a similar question the other day. A short cage can accomodate your 25T in the rear and your double set up. I think the purpose of a long cage is really to take up the slack from the combination of a bigger cog in the rear and jumping around from the smallest chainring to the biggest one..

I'm new to this CX thing so I might be full of crap.
bluenote157 is offline   Reply With Quote
Old 09-10-08, 12:18 PM   #4
adamt
Senior Member
Thread Starter
 
adamt's Avatar
 
Join Date: Aug 2008
Location: Portland, OR
Bikes:
Posts: 427
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
cool

so maybe a Shimano RD-M772 XT Rear Deraillier in the midcage would be a good bet.

will it accommodate a 12-27 if I needed it to?
adamt is offline   Reply With Quote
Old 09-10-08, 01:09 PM   #5
knobster
.
 
Join Date: May 2006
Location: Hillsboro, Oregon
Bikes: Specialized Roubaix Comp, Soma ES
Posts: 3,982
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
The short cage RD will support the 12-27. I've read where people have used 12-34 with a RD before. Just don't cross chain!
__________________
Demented internet tail wagging imbicile.
knobster is offline   Reply With Quote
Old 09-10-08, 01:12 PM   #6
scattered73
Justin
 
scattered73's Avatar
 
Join Date: Jan 2007
Location: Bayou City
Bikes: Soma Double Cross, KHS Urban Uno
Posts: 1,051
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I have used ultegra short cage rd with a 12-27 before no problems at all.
scattered73 is offline   Reply With Quote
Old 09-10-08, 01:27 PM   #7
flargle
Senior Member
 
Join Date: Jul 2007
Bikes:
Posts: 2,119
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Quote:
Originally Posted by adamt View Post
It would seem to me running an XT rear would be better than an Ultegra set up.
Why?
flargle is offline   Reply With Quote
Old 09-10-08, 01:42 PM   #8
adamt
Senior Member
Thread Starter
 
adamt's Avatar
 
Join Date: Aug 2008
Location: Portland, OR
Bikes:
Posts: 427
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Why?

I would just guess that the XT and other mountain stuff would be a bit more willing to take a beating.
adamt is offline   Reply With Quote
Old 09-10-08, 01:53 PM   #9
sfcrossrider
Senior Member
 
sfcrossrider's Avatar
 
Join Date: Mar 2006
Location: San Francisco
Bikes: Steelman eurocross, Surly CrossCheck, IRO Rob Roy...
Posts: 2,760
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
My Campy, Record rear works with an 11x30 setup.
sfcrossrider is offline   Reply With Quote
Old 09-11-08, 09:50 AM   #10
cachehiker
Soma Lover
 
Join Date: Dec 2004
Location: Logan, UT
Bikes: one bike for every day of the week
Posts: 765
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by adamt View Post
Is there a reason NOT to go with the mountain rear derailleur?
An Ultegra double RD is lighter and will shift a 12-25 or 12-27 cassette better than an XT mid cage. With a 44-34 crank you should be fine on all but the steepest climbs but you could also spin out above 30 mph. There would be enough chain wrap left over to consider a 46-34 or 48-34 crank though. I wouldn't use it with a mountain bike cassette.

Quote:
Originally Posted by adamt View Post
so maybe a Shimano RD-M772 XT Rear Deraillier in the midcage would be a good bet.

will it accommodate a 12-27 if I needed it to?
I use and prefer an XT mid cage myself. I run a 38-48 crank with 9 speed cassettes and it lets me commute through the summer with an 11-28, race cross in the fall with a 12-27, and ride the odd trail with an 11-32. However, it limits you to a 10-12 tooth difference in the front if you plan on running a mountain cassette.
cachehiker 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 11:05 PM.