anybody know what the largest cassette size i can use with a medium cage 10 speed ultegra rear mech???

want to build up a cotic escapade as a 1×10, commuting, winter trainer, pootle about bike. 40tooth at the front and would like 11-34 at the back for the hills. i have some ultegra shifter/brake levers so need to stick with shimano road at the back (unless someone knows something clever?)
cheers

I believe it will handle 32T bit you can fit a 9-speed MTB mech, say an XT, and that will definitely handle 34T

the shifters are coming off a salsa fargo that i built up with 10speed ultegra shifters, 9 speed xt rear mech. could never get the shifting to be anything better than 8/10 despite constant adjustment and a new mech. always skipped on way down or just sat jumping between. finaly givn up and going over to sram (bank loan pending!!).

Eh? So are you going to SRAM, or do you want to use your Ultegra mech…?

Are u using a shadow mech or pre shadow I found pre shadow to work fine have old deore lx on the crosser and tx on the roadie

medium cage old 10 speed 28t
medium cage new 11 speed 30t

long cage old 10 speed 30/32t
long cage new 10 speed 32t

the difference between the long and medium cage apart from capacity is the top of the cage has a flat filed onto it to clear the 32t, so you can literally take a file to one (6700RD) to get it to fit 32t, medium cage won’t have the capacity though (if double chainring?)

I had a medium cage 105 working with an ultegra cassette with a 30. Seemed to run smooth – I used it offroad on a croix de fer.