Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

Switching from road rear derailleur to a mtb derailleur

Notices
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.

Switching from road rear derailleur to a mtb derailleur

Old 08-22-10, 01:24 PM
  #1  
jmeans53
Junior Member
Thread Starter
 
Join Date: Aug 2010
Location: Kansas
Posts: 6
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Switching from road rear derailleur to a mtb derailleur

I recently bought a cx bike and have broke my rear derailleur (Shimano Tiagra) on a pretty challenging trail ride. After doing some research, I thought it would be a good opportunity to upgrade and I also read some posts about switching to a MTB derailleur. I have a new Shimano RD-M772 XT Shadow. I guess I don't fully understand and am having issues b/c I can't shift to either gears 1 or 9 with this derailleur. Do I need to put a different cassette on? Currently I have a SRAM 9-speed, 11-26T. Is there any other modifications I need to make for this to work?

Crankset: FSA Vero Aluminum Forged crankarms, 50/39/30T Chainrings, 130BCD
Shifters: Shimano Sora 9-speed

I'm new to this cx thing (really I'm new to cycling in general) so I appreciate everyone's thoughts/help.
jmeans53 is offline  
Old 08-22-10, 02:04 PM
  #2  
dnuzzomueller
Banned.
 
Join Date: Apr 2010
Location: Somewhere
Posts: 1,041

Bikes: something

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
In general switching between any single manufacturers stuff is alright with a few exceptions.

In your case as long as the new derailleur is not labeled as being Dyna-Sys then you should see no problem going to a mountain derailleur. The one thing a mountain derailleur will give you that you could take advantage of IF you were to swap to swap to a different rear cassette is a larger range so if you wanted to you could get something like a 11-32 (hypothetically speaking, you still need to check the max range and gear capacity on your derailleur)

If I am wrong though about any of this someone is free to correct me (As I know someone will )
dnuzzomueller is offline  
Old 08-22-10, 02:27 PM
  #3  
fietsbob
Banned
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 43,599

Bikes: 8

Mentioned: 197 Post(s)
Tagged: 0 Thread(s)
Quoted: 7607 Post(s)
Liked 1,315 Times in 826 Posts
neither 1 nor 9? suggests the limit screws, Hi & Low, are too tight. and the travel is limited...
fietsbob is offline  
Old 08-22-10, 03:19 PM
  #4  
LarDasse74
Guest
 
Join Date: Jul 2008
Location: Grid Reference, SK
Posts: 3,768

Bikes: I never learned to ride a bike. It is my deepest shame.

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
The derailleur is compatible. I can't say why the deraileur is not working, but I have two suggestions for you -

1. Takethe bike to a shop and have them check the deraileur hanger alignment. If it is misaligned by only a tiny bit your shifting will be crap, and possibly cause your deailleur to get stuck in the spokes and torn off.

2. Go to parktoool.com and follw their step-by-step instructions on setting up a derailleur. If the hanger alignment is correct and the derailleur is compatiblle with the shifters and cogs (yours is 100% compatiblle, by the way) then setting up a derailleur is dead simple if you follow their instructions.
LarDasse74 is offline  
Old 08-22-10, 03:58 PM
  #5  
jmeans53
Junior Member
Thread Starter
 
Join Date: Aug 2010
Location: Kansas
Posts: 6
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Thanks for the replies...I'm glad to know that everything is compatible...now I just have to figure out what I've done wrong
jmeans53 is offline  
Old 08-22-10, 05:07 PM
  #6  
Bezalel
Senior Member
 
Join Date: Mar 2010
Location: City of Brotherly Love
Posts: 1,561

Bikes: Raleigh Companion, Nashbar Touring, Novara DiVano, Trek FX 7.1, Giant Upland

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 19 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I wouldn't reccoment using a Mountain Derailleur with a road cassette. In the lower gears the guide pulley will be further away from cogs and shifting won't be as smooth.
Bezalel is offline  
Old 08-22-10, 05:41 PM
  #7  
jmeans53
Junior Member
Thread Starter
 
Join Date: Aug 2010
Location: Kansas
Posts: 6
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
If I do decide to go with a mountain cassette what type should I use? I've read some poor reviews on the shimano m770 but I don't want to spend the $$ for the m970. Are there any alternatives? Does anyone have experience riding either of the two I mentioned?
jmeans53 is offline  
Old 08-22-10, 05:53 PM
  #8  
Shimagnolo
Senior Member
 
Shimagnolo's Avatar
 
Join Date: May 2008
Location: Zang's Spur, CO
Posts: 8,970
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 2455 Post(s)
Liked 2,197 Times in 1,132 Posts
Originally Posted by jmeans53 View Post
I guess I don't fully understand and am having issues b/c I can't shift to either gears 1 or
9 with this derailleur. Do I need to put a different cassette on? Currently I have a SRAM 9-speed, 11-26T.
You didn't adjust the Hi and Low limit screws.
In my recent experience, Shimano has been shipping RD's with both cranked in, so both need to be backed out when adjusting at installation.
(I just installed an M772 yesterday).
And due to the relatively small size of your large cog (compared to a mtn cassette) I am sure you will also need to adjust the B screw to bring the upper pulley 5-6mm away from the large cog in the lowest gear.
Shimagnolo is online now  
Old 08-22-10, 07:13 PM
  #9  
CCrew
Older than dirt
 
CCrew's Avatar
 
Join Date: May 2008
Location: Winchester, VA
Posts: 5,342

Bikes: Too darn many.. latest count is 11

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Originally Posted by Bezalel View Post
I wouldn't reccoment using a Mountain Derailleur with a road cassette. In the lower gears the guide pulley will be further away from cogs and shifting won't be as smooth.
It'll work just fine though.
CCrew is offline  
Old 08-22-10, 08:19 PM
  #10  
jmeans53
Junior Member
Thread Starter
 
Join Date: Aug 2010
Location: Kansas
Posts: 6
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Thanks for the help...I adjusted the limit screws and it's shifting great (so much better than the tiagra that was on there originally).
jmeans53 is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
trail_monkey
Bicycle Mechanics
0
09-09-18 01:03 PM
convrtdsuthernr
Mountain Biking
11
01-02-17 04:12 PM
anjhaankit
Bicycle Mechanics
23
01-01-16 07:09 PM
Troggie
Bicycle Mechanics
4
04-07-15 07:33 PM
ReVolts
Mountain Biking
0
02-17-10 01:38 PM

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


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.