Learned Beardies

I get my repaired Salsa Casseroll back from Joe Cosgrove tomorrow and need to purchase a new derailleur as well.
Previously I had a short cage 10 speed ultegra rear mech to Indexed 10 speed down tube shifters.
I am thinking of using mtb gearing (32-12) and probably an XT rear dérailleur.
My question is, will this setup work with my down tube shifters?
Thanks for any responses.

Yes, no probs.

My understanding is if you want 10-speeds, Shimano road 10-speed has a different cable pull than Shimano MTB 10-speed Dyna-sys.

Shimano is releasing a new 105 and Tiagra RD-5701 and RD-4601 rear derailleur which can can handle up to 32T cassette, which might be an easy work-around:

Shimano Sora And Tourney 2013 ? First Look - BikeRadar

While the standard 6700 rear mech can only be used with up to 28-tooth sprockets, the new 6700-A can handle 30. It’ll work with close-ratio gearing too, down to 11-23t, and is available in SS (short cage) and GS (medium cage) versions, in silver or black.

The mid-range 105 and Tiagra groups also both get new wide-ratio rear derailleurs. The 5701 (black or silver) and 4601 (silver only) rear mechs can both be used with cassettes between 11-25t and 11-32t, and come in SS and GS variants.

Edit, like spirito says if you want 9-speed with the last limited off, this is no problem.

Thank you gentlemen.
Viva Le Beard!

9sp MTB mechs work fine with 10sp road levers.

oops … I stand corrected. Guess I gotta reads more product info’s !!

Yes, LWAB has it right. Use a 7 or 8 or 9sp MTB mech with your 7 or 8 or 9 or 10sp road (But not early 6/7sp DA or current DA) shifters and you are good to go.

No limiting out gears, no other faffery.