Will this work?, I vaguely remember hearing it won’t.

Assuming you mean an 11s xtr shifter then I can’t see why not.

Yep both 11sp.

Why wouldn’t it? Even Shimano have yet to build incompatibility within their own hierarchies (9/10/11 speed aside)!

Didn’t Shimano claim the XTR mech wouldn’t work with the 42T cassette? People have it working with SRAM cassettes though, so clearly it will work.

That’s what I thought but wanted to check.

I think it will work. A friend of mine has xtr DI2 shifter and rear mech working fine with a SRAM 11 speed cassette. Im thinking that new XT will be a good replacement for X1 when I trash the rear mech as its so much cheaper.

No problem with XTR M9000 rear mech on 11-42. The 11-42 is 1x specific, but not XT specific.

Even Shimano have yet to build incompatibility within their own hierarchies

OK – going off topic a bit, but let’s not mention the first Dura Ace and Ultegra Di2 (10 speed) groups, which had incompatible wiring.

I think the more heinous crime was that when they did 11 speed Di2 you could use the 10 speed Ultegra mechs/STIs, until they removed the reverse compatibility in a software update. Then stopped producing 10 speed Ultegra Di2, so it’s basically useless now if you break something.

But anyway, we digress.

they removed the reverse compatibility in a software update

Now I’m really feeling old.

OK, so what are the constraints/options around 11spd?
I’m about to press the button on a new bike which will come with X01 group. I’don’t fancy replacing the rear mech with the same every time I trash one, 11spd XT would make a lot more sense.
So, I think that means that pretty soon after I’ll end up with XT shifter and mech on an XD hub and SRAM cassette.
Would it make more sense to install XT cassette and std hub from day one?

Is there a market for X01 mech, shifter & cassette unused?

Is there a market for X01 mech, shifter & cassette unused?

Yes, I would think so.
Better now than waiting until everyone knows about XT 11sp.

Worth noting that the Sram GX mech is currently £73, so not toooo bad compared to the others.
Still easy to see XT coming in at half the price eventually though.

Have we figured out yet if Shimano 10 and 11 speed bits are interchangeable (i.e. can you run an 11 speed shifter with a 10 speed mech?) or is it the same situation as 10/9 speed?

It will work. I updated my running gear on Tuesday to the following:

XT 11-42 11sp Cassette
XT 11sp Mech
XTR 11sp Shifters

That was mated to my existing SLX cranks with Raceface 34t thick/thin chainring and 10 sp chain.

No issues – works brilliantly.

Awesome, cheers tubthumped! I just ordered an XTR shifter, new XT shifter is pretty ugly IMHO, I need ispec B for my Hope brakes and it’s not out for a while, and i can’t be doing with shift windows.