I fitted my XT 10 speed set up on Friday night for 10 More at Moray. Thought I'd do a "first impressions" write up that's not from a journalist. I figured that 60 miles pounding the stuff at warp speed 8 was a good enough basis for a wee review.
A bit of background-
1- XT shifter
2- SLX cassette
3- I'll be swapping to XTR when it comes out on the race bike
4- 1×10 with e13 XCX guide and 36T rear cassette/32T ring.
5- Ultegra road chain with Sram Powerlock.
Right, first things first- no, your old rear mech won't work with it unless you bodge it. The cable pull IS different (which sadly contradicts what Madison told me) but it's easy enough to work out a way around this. Fortunately I had all 10 gears available to me.
Shifting- the XT shifter is better than the 9speed one. It's impressively better, I'd not normally notice this sort of thing as I'm not the most anal with stuff like that. The shifting is lighter, easier to do through the range but also the click is more defined. It's the usual delicate Shimano shift, though, not a Sram clunk. Pick up on the trigger is quicker than of old too, but it's not XTR quick yet. I'd say it feels almost as good as 9speed XTR. Not quite there, but almost.
Range- 32/36-32/11 was fine. I'll be honest, the course at Moray didn't warrant ever going past about the 3rd gear at the back but a usual ride with steeper hills would be very much manageable. The SLX cassette is nicer than of old and very nicely made.
Anyway, 10 speed Shimano is good. Really really good. 1×10 is wonderful for me but I can see it being not for everyone.