A question for the techno-my racing roadies out there.

I’ve got a 2014 Specialized Roubaix to which I’ve added Ultegra Di2 10 speed. I’m currently running a 30 tooth sprocket but would like to increase this to a 32 tooth. I’m being told that this isn’t possible with my current setup and that the only option will be to change to Di2 11 speed and run a 11 32 cassette. This will mead not only a new block and chain but also new front and rear mechs!

Has anyone managed to run a 32 tooth sprocket with di2 10 speed?

To run a 32 cassette you would require a GS or medium cage rear mech. How interchangeable the 10 and 11sod stuff is I really don’t know. But knowing shimano it wouldn’t at all surprise me if to run 11spd you would need the entire set up, shifters, mechs, the whole nine yards. Otherwise scour the classifieds or eBay for a GS 10spd rear mech.

Has anyone managed to run a 32 tooth sprocket with di2 10 speed?

yes, i did it hacked onto a MTB with a 7090 Di2 Mech and a 11-32 XX 10 Speed Cassette,

also currently running a 9070 Di2 11 Speed mech with a 11-32 Ultra Cassette

works perfect, just screw in the b-tension screw a little bit more

I’m also running a 32T 10 speed cassette on Di2. Works fine for me, with 46/36 on the front.

You might need to watch the chain tension if you are on 52/34 though.

Cheapest way to find out is to buy the cassette, I don’t think that any text book will be able to say for sure.

just to counter the above, i run a 52/36 mid compact – no issues

can’t mix different speed front an back but you can mix shifters.

You could with the external battery but they fixed that..

Encouraging to see that others are running 32T on 10 speed Di2 with no real issues. it seems that the ability to do so can come down to the length of the mech hanger.

I’ll get a 32T block and try it out and report back.

Thanks all.

I fitted a Sram 12-32T cassette this evening together with a new chain. Bit of getting with the B screw and rejigging of the indexing and all’s good. Did a 27 mile ride with over 2,000ft of climbing and it didn’t miss a beat.

All set now for Sunday’s Rallen Leaves ride!