mtb/road component compatibility for cyclocross
 

I have a cx bike currently built up with road hubs and 2010 Ultegra. I want to start running a 10 speed XT cassette for more gearing range (I already have an XT rear DR in my parts bin). My question is somewhat twofold. The first is if an XT 10 sp cassette will fit on a road freewheel, the second is whether the cog spacing is compatible with an Ultegra road shifter.
The frame is a cross check, and I have several XT hubs that I could perhaps lace to a road or a 29er rim if the XT cassette won't run on a road freewheel.
Any input is appreciated.

The 10-speed XT cassette should fit any Shimano 8/9/10-speed hub and be spaced the same as a road cassette. The XT rd will work with your Ultegra STI brifters.

Seems FDs mtb ones on road Brifters Shimano stuff is a bit of a mismatch people have mentioned

Bar end works with all.

Its for a cx racing bike, bar end shifters get in the way and my knees hit them. I have bar ends on my touring bike.

thanks, pretty much exactly what I was hoping for. I might just give it a try tonight if the LBS has a cassette in stock.