Zach_Stone

Will 10 speed Ultegre (6600) shifters work with a 9s XT derailleur? I know the 10s dynasys XT will not, but I was hoping the 9s might.

cycle_maven

Yes, but you have to route the cable differently on the rear derailleur. Here's how:
https://sheldonbrown.com/dura-ace.html#alternate

I like to put the extra click at the tightest cable position and keep it from happening by using the limit stop on the rear derailleur, but others say to put the extra click at the slack position. Either way is OK, but if you use the tight cable, be absolutely sure that you don't make that last hard overshift- you'll have to disconnect the cable to free it up, and you could break your shifter if you try to force the upshift.

ct-vt-trekker

The alternate cable routing only pertains to using a 9-sp cassette with 10-sp shifters, this is not what the OP asked.

Yes using a pre-dynasys XT rear derailleur will work fine with 10-sp Ultegra shifters. This is the standard setup for Tandems and touring bikes that need a long cage rear derailleur.

HillRider

The rear derailleur has no "clicks", extra or otherwise. Your advice works only if he is going to use a 9-speed cassette which wasn't mentioned. If the OP uses a 10-speed cassette, 10-speed shifters and a 9-speed XT rear derailleur, everything will function properly.

oldbobcat

Yes, they do work. This is the recommended solution for riders who need wide-range cassettes (10-sp, to match your shifters) to climb hills or carry loads.

You might need a longer chain (10-sp). It should allow you to use big-big, even though you might not plan on it. Someday you might go there by mistake and your chain better be long enough. Then set your limit screws and cable tension and away you go.

Kimmo

There's nothing in the OP to indicate whether 9 or 10 cogs are being used.

HillRider

True but the rear derailleur still doesn't click no matter what.

Kimmo

The only person here talking about clicks in a derailer is you, AFAICT.

@cycle_maven is referring to the decision of which 9/10 shifter clicks to use by either locking out the first or last click via cable adjustment, and mentions how the low limit (mostly) prevents the first click if you lock that out.

(Not the case if you go the other, safer* way)

* DT/stem/thumb shifters, barcons and Ergos with the big slot under the mouse ear don't give a crap, it only hurts ratcheting indexed shifters.

HillRider

You are right except cycle_maven addressed a 9-speed cassette possibility and that was never mentioned in the OP either. All he asked was can a 9-speed MTB rear derailleur be used with a 10-speed brifter. The simple answer is yes.

Zach_Stone

Thanks much! As the rest of the parts were 9s (chain, cassette, etc) I flogged the shifters off on a friend who wants 10s and indexing and went with retroshift levers and older 600 dt shifters as I don't really need indexing for now. May buy some 9s dura ace dts later.

HillRider

If you do decide to go to indexing shifters on those Retroshift levers in the future, consider getting the shifters (Microshift) that Retroshift sells in either 9 or 10-speed form. They are less expensive than Shimano dt shifters and much easier to shift. The Shimanos are quite stiff to move and a bit difficult to operate on the Retroshift levers. I have 10-speed Retroshifts on two bikes, one with the Microshift shifters and the second with Dura Ace SL-7900 shifters. The Microshifts are MUCH easier to use.

cycle_maven

I guess I made the assumption that the rest of the drivetrain was 9-speed. Turned out to be right, but the simple answer was "yes, the shifters work with that derailleur".