DA 7800 Road Shifters with ? Mtn Rear Derailleur

Discuss light weight issues concerning mountain bikes & parts.

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Rick
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Joined: Sat Aug 29, 2009 4:30 pm

by Rick

I did search, but couldn't find a clearly definitive answer.
Which long cage rear derailleurs, for use with an 11-32 10-spd cassette, are compatible with DA 7800 and/or Ultegra 6600 series front road shifters for a road setup?
I think Shimano changed the cable-pull amount on their newer mtn derailleurs, right ?
I think the RD-M591 will work ?
any of the newer XT or XTR models ?

Thanks.

by Weenie


HillRPete
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Location: Pedal Square

by HillRPete

I'm running an Ultegra 6700 GS rear mech ("long cage") with an 11-34 cassette here. Shimano RDs typically handle a bit more than said in the spec, to account for subtle differences in frame/hanger measurements.

You can also use any Shimano 9 speed MTB RD with a 10 speed road shifter and 10 speed cassette, the cable pull is the same. Running Ultegra flatbar 10-speed shifters with 9sp SLX RD and XT cassette on one of my bikes, works a treat.

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Rick
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Joined: Sat Aug 29, 2009 4:30 pm

by Rick

Thanks. Please forgive my ignorance about mountain components.
If any 9-speed derailleur will work, then does that include the newer "Shadow" style, like the XT M772 ?

Is the "shadow" design a real improvement ?

HillRPete
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Location: Pedal Square

by HillRPete

Turns out I'm even running a "shadow" RD -- RD-M662 SGS to be precise. Works flawlessly, the cable pull got to be the same as for the regular models, otherwise you'd need "shadow" shifters as well.

TheRookie
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by TheRookie

Shadow is only the design of the mech, tucking in away from damage, it doesn't effect the shifters at all.
Impoverished weight weenie wanna-be!
Budget 26" HT build viewtopic.php?f=10&t=110956

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Rick
Posts: 2001
Joined: Sat Aug 29, 2009 4:30 pm

by Rick

OK....so I am actually going to try an XTR RD-M971 SGS
That's a long cage, conventional 9 speed.
I got a good deal on a new take-off on ebay.
They don't come with barrel adjusters any more, but IRD makes a barrel adjuster specifically for shimano's now-omitted part. So I will report back when I have tried it all together.

Megaclocker
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Joined: Wed Dec 17, 2008 5:39 pm

by Megaclocker

shimano road shifters will work on any non-dynasys rear derailleur.

andrewh8877
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Joined: Mon Sep 14, 2009 8:51 pm

by andrewh8877

I have a 10sp 105 shifter and that worked well with an XTR M972 Shadow rear mech,

by Weenie


maxxevv
Posts: 1949
Joined: Wed Feb 09, 2005 4:51 am

by maxxevv

10 speed Road shifters will work properly with 9-speed designated MTB Rear Derailleurs.

I have run 7800 shifters even with a 9 speed 'shadow' XT RD before ( that's quite a few years ago, so I can't recall the RD number though...). It shifts perfectly.

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