dwmckee

I am building a touring bike and hope to run a 9 speed 12-36 cassette on the rear with drop bars and STI shifters. Can I run an XTR rear derailleur with 9 speed STI shifters? (I know the XTR front derailleur is not compatible with STI shifters so I am planning to use an Ultegra front derailleur.)

Thanks for your help.

Don

surreal

Which XTR rear derailer? An older 9speed version would work nicely, but the 10speeds are s'posedly not compatible with 9 speed shifters/cassettes, due to slightly different pull ratios.

Shimagnolo

It isn't "slightly", the 10s mtn "Dyna-Sys" cable travel is about *twice* the travel of the 9s RD's for the same amount of RD movement.
I had one here for experimental purposes.

surreal

Touche. But,let's remember, 2cents is only slightly more than 1cent, even though it's twice as much. Some glasses are half-full; others are half-empty, etc.
It's a moot point; dyna-sys is the exact reason why i (finally) decided to boycott Shimano. I used to love 'em.

Kimmo

Don't imagine Dyna-Sys is merely planned obsolescence; Shimano should have changed their RD's actuation ratio when they came up with 8s.

It's long overdue - double the cable pull is a welcome improvement, and compatibility hassles are as nothing next to systems so finicky they only work properly when everything's in perfect condition.

surreal

It may not be "merely" planned obsolescence, but there is certainly a planned obsolescence facet to the situation. And, let's face it, those new chains are just a rip-off designed to fleece the customer.

I'm done. I'll keep my indexed stuff working as long as I can, then i'll move to friction forever.

cyccommute 

Yes, you can. It's not a problem. I have two road bikes using 9 speed XTR rear derailers with STI shifters. It's not an issue nor difficult to set up.

When they came up with 8 speed? Keeping a 9 speed derailer working perfectly isn't difficult at all and keeping a road rear derailer on a 10 speed system...which uses the same cable pull...working perfectly isn't difficult either even in severe mountain bike conditions. Neither systems are 'finicky' in my experience.

calamarichris

I just built up one of my Pelotons with this very same setup, thanks to the guidance of the kind souls in this very forum. Found an NOS pair of 7700 brifters and they work perfectly with the modern XTR cassette & RD. Only hitch is that I had to go with a 7700 front derailleur too, because the 9-speed chain is of course wider than the 7800, and rubbed lightly at the gearing extremities.

hamster

It's not double. I tried to hang a dynasys RD on a road bike a while back, it was travelling 7 or 8 rings (out of 10) over the range of the shifters.

It is a completely pointless change whose only purpose that I can see is to make things incompatible with each other.

demoncyclist

As already pointed out, DynaSys has a different pull ratio and will not work, but any earlier 9S or 8S Shimano mountain rear derailleur will work just fine with road STI levers.

dwmckee

What model rear derailleur did you use then? A new one or an older 9 speed?

Thanks,

Don

calamarichris

New one.

hamster

The one in the picture ^^^ looks exactly the same as the one I tried to put on mine, which was dyna-sys. If it is the correct picture, I have no idea why it's working for you.

gyozadude

Nashbar seems to have a big sale/closeout on first gen XTR dyna-sys RD. Was tempted to buy one but looking for compatibility and so I stopped myself even though the price was good. I found buying a long arm Microshift version was indeed more compatible and cheaper. That might be an option, unless having the "all Shimano" gruppo label on the bike is important.

dwmckee

I think that is the RD-M772 SGS. I guess I'll have to just plug it all together and wire it up then and see how it goes. Fingers crossed.

Thanks everyone! You guys rock as always!

Keep the rubber side down...