Di2 max cassette

Neilscc
Neilscc Posts: 5
edited April 2016 in Workshop
I have the Ultegra 11 speed Di2 with a standard rear mech. The cassette is 11-28 with a compact crank. I am planning two rides with significant climbing over 20% to 30% and feel the need for a bail out gear over the 28.
What are my options, I seem to remember the max could be 28 tho', has anyone managed bigger or a work around without buying a new mech?
Ta

Comments

  • meanredspider
    meanredspider Posts: 12,337
    On 10-sp I managed to get 30T and see no reason why that should be different for 11sp.

    Another solution which I employed on my day climbing The Alpe was to fit a 33 small ring up front. Dunno if it's available for 11-sp
    ROAD < Scott Foil HMX Di2, Volagi Liscio Di2, Jamis Renegade Elite Di2, Cube Reaction Race > ROUGH
  • 964cup
    964cup Posts: 1,362
    Depends on your hanger geometry. A 30 should be possible. Some claim to run a 32 but you will run out of capacity, so even if the mech will take the cassette, you won't be able to run cross-chained without either having the chain too tight, or too loose. Better to fit a GS mech, which will take a 32 with ease.

    The 33T small ring is also a plan - Wiggle do a TA Specialites ring that will fit most standard 5-bolt 110bcd cranks.
  • Neilscc
    Neilscc Posts: 5
    Cheers, never really thought of changing the front, might have a look for a 30 on the rear too, I think a 32 might be pushing it
  • Neilscc
    Neilscc Posts: 5
    As the rear mech is limited by its capacity, the difference between biggest ratio and smallest ratio, could I change the front small cog to a 36 and the cassette to a 11/32? This would extend down my gear inch from 32 to 30 without the need for an expensive new Di rear mech. The cost would be under £50 all in whereas the rear mech is 115 on its own?