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


Go Back   > >

Touring Have a dream to ride a bike across your state, across the country, or around the world? Self-contained or fully supported? Trade ideas, adventures, and more in our bicycle touring forum.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 09-03-10, 11:38 PM   #1
Six jours
Senior Member
Thread Starter
 
Join Date: Mar 2007
Bikes:
Posts: 6,401
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Dura-Ace 9 speed downtube shifters compatible with mountain bike rear derailleur?

For various irrational but otherwise perfectly valid reasons I'd like to use Dura-Ace 9 speed downtube indexing shift levers and a 32 or 34 tooth maximum cog. As far as I can tell those cogs require a "mountain bike" derailleur. The spec sheets for Shimano's mountain bike derailleurs usually say something like "Compatible with all mountain bike shifters" so I'm not convinced the DT shifters will work with the off-road derailleurs.

Anybody know the facts?
Six jours is offline   Reply With Quote
Old 09-04-10, 12:00 AM   #2
NeilGunton
Crazyguyonabike
 
Join Date: Nov 2003
Location: Albany, OR
Bikes: Co-Motion Divide
Posts: 684
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 29 Post(s)
It's funny you should bring this up now, because I just had this very discussion with Shimano a couple of days ago myself. Recounted on this thread over on crazyguyonabike:

http://www.crazyguyonabike.com/forum...read_id=185783

In a nutshell, I had 9-speed Dura Ace bar end shifters (i.e. "road" shifters) combined with the Shimano XTR RD-M971 rear derailleur (i.e. a "mountain" derailleur). I was getting problems with ghost shifting - if I dialed it in at one end, then it would start skipping on the other end. Shimano told me that this derailleur may experience this type of problem with these shifters. According to them, the only shifters that are officially compatible with their "mountain" derailleur are the MTB trigger shifters. On an earlier conversation with a different Shimano rep, my bike shop guy was told that it's specifically the 971 derailleur that's having the problem, and earlier versions of the XT didn't have the issue. This is second hand, though, and I didn't get any more details about exactly which models would or wouldn't work. The guy I actually spoke to didn't tell me this, he just said flat out that mountain derailleurs won't work well with road shifters, period.

In any case, this was all a bit of a revelation to me, since I thought that 9-speed was 9-speed, I didn't realize there might be issues with mixing road shifters with mountain derailleurs. But there you go, two separate phone calls to different Shimano tech reps said pretty much the same thing.

But the thing is, I know that plenty of bikes are sold with this combination, so many people (most perhaps) never see this problem manifest... but I did (of course, if there's a potential problem then I'll probably see it). So it's just something to be aware of.

Incidentally, my "solution" was just to get a bit creative and go over to SRAM Gripshift + SRAM X.9 derailleur on the rear. It seems to shift correctly in all combinations, at least in the bike shop on the stand. I hacked some MTB bar end extensions to fit onto my drop bars, see the linked thread for details. I'll be testing the setup properly tomorrow.

Neil
NeilGunton is offline   Reply With Quote
Old 09-04-10, 01:09 AM   #3
Deanster04
Senior Member
 
Deanster04's Avatar
 
Join Date: Dec 2005
Location: Boulder, Colorado
Bikes: Cinelli Supercoursa 69, Ritchey Breakaway Cross, Mondonico Diamond Extra 05, Coors Light Greg Lemond (built by Scapin) 88, Scapin MTB, Stumpjumper 83, Specialized Stumpjumper M4, Lemond Poprad 2001
Posts: 1,366
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I am using Dura Ace 9 spd bar ends with a mtb bike cassette 11-34 and the performance MTB derailluer without any problems...including a summer in the Alps: Austria, Julian, Dolomites, and sud triol. Another person on the ride used an SLX RD with the same cassette with no problems. There is a setup issue with the Barends where the last shift point 11 has a hitch that can be removed by someone who really knows the shifter can tune out. Once setup no shifting problems at all. I think the DT shifter has a positive stop and this problem may not occur. In any case It works for me.
Deanster04 is offline   Reply With Quote
Old 09-04-10, 07:24 AM   #4
BillyBob
Senior Member
 
Join Date: Jul 2004
Bikes:
Posts: 462
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Works for me on a trek 520. LX derailuer with dura ace down tube shifters.
BillyBob is offline   Reply With Quote
Old 09-04-10, 07:26 AM   #5
gorshkov
Senior Member
 
Join Date: Apr 2009
Location: Tulsa, OK
Bikes: Raleigh Sojourn, Trek X-Caliber, Trek Antelope
Posts: 282
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by BillyBob View Post
Works for me on a trek 520. LX derailuer with dura ace down tube shifters.
Worked for me twice: once with LX, and once with Deore.
gorshkov is offline   Reply With Quote
Old 09-04-10, 07:31 AM   #6
Bekologist
totally louche
 
Bekologist's Avatar
 
Join Date: Oct 2004
Location: A land that time forgot
Bikes: the ever shifting stable loaded with comfortable road bikes and city and winter bikes
Posts: 18,025
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
derailleurs are dumb, the indexing is all in the shifter.

I have seen bikes outfitted with STI and mountain rear derailleurs, and downtube and mountain derailleurs, and a whole heck of a lot of bikes with barends and mountain derailleurs.

Earlier this week I helped a woman set up her 10-speed STI bike with a new 10 speed 11-34 cassette and an SLX rear derailleur for lower gearing.

No problems!
Bekologist is offline   Reply With Quote
Old 09-04-10, 10:02 AM   #7
Six jours
Senior Member
Thread Starter
 
Join Date: Mar 2007
Bikes:
Posts: 6,401
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks all. Sounds like excepting a bit of bad luck this should work.
Six jours 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 07:53 AM.