For what it is worth I am using a FC9000 11speed crank on a otherwise 10speed 6700 system including the 10sp chain with 0 issues. Common sense would tell me that if my setup works then a 10sp crank should be fine with a 11sp chain.
From what I've learned over the last few years, there's a lot of room relatively with front chain rings. I wouldn't try and run a 10/11 spd chain on a 7 spd front chainring but I think you can safely move around between 10 & 11. I even know a mechanic who swears by running Campy 11 spd chains on 10 spd Shimano drive trains.
Augh, I had things the other way around in my mind. 11 speed hub is backwards compatible with 10 speed cassette with said spacers.
Yup! Was talking to some Shimano techs and they said "We've learned our lessons about making things non-backwards compatible." Currently running 11spd C24's as well as 11 spd R45's and they both run flawlessly with the spacers.
i am think to get the 6800 upgrade set from here: http://www.excelsports.com/main.asp?...ajor=1&minor=5
But they dont come with the crankset, did any one know if my 10 speed crank will work with this 11 speed set.
And already order my new wheelset with 11 speed hub.