Di2 10 Speed

[Lovey1]

i am looking to replace my 6770 10 Speed Ultegra rear mech. as i am having some battery drain issues. Replacements are impossible to get hold of so need to buy an 11 speed. Can anybody confirm that i can reprogram an 11 speed to 10 speed. Thanks

Edited by Lovey1 on Monday 8th March 15:36

[SoliD]

I'm 90% certain yes, it's just an up down paddle and has the standard 2 cables inside. it's only the early dura-ace stuff that doesn't work with anything else. I don't even think it'll need reprogramming, should just be plug and play as the derailleur controls itself as far as I'm aware and would need to be changed to 10sp not the other way around.

[esuuv]

You can't "covert" 11 speed to 10 - the rear derailleur is governing so an 11 speed will give you just that - you would need a new cassette (possibly hub) and chain - you would get more ratios though. You would have to change the front derailleur too as since about 2016 the firmware has stopped you mixing and matching between 10 and 11 speed. This is most of the reason 10 speed mechs have become so rare.

There's a compatibility chart on the Shimano website