That's more reassuring info. I'm sure no one at shimano wants this as widely known since it may cannibalize the newer 9070.
I would be willing to try it but my existing hub is 10 sp.
Are the 7900 cranks 11 sp chain compatible? I'm particularly curious about chainring teeth thickness.
If the 9070 RD is a can bus network the 9070FD may work as well.
Incorrect. My Shimano rep says change the RD and Cassette and you're good to go.10spd and 11spd will be determined by the shifters, not the deraillieurs. So if you have 6770 and you add the 9070 rear brifters, you system should automatically become 11spd.
And the same can be said if you want to use your 10spd wheels on 9070. You must have 6770 brifters for it to work.
It was irresponsible for your tech to say that, when it is not possible. The throw of the 6070 is not enough and there is no program to support it regardless (and I'm not one for hacking it to have little support and sketchy functionality, all for one more cog).Why the rd? It was suggested to me by Shimano techs that 6070 will do 11. They said travel was the issue, but 10speed der has plenty of extra movement to cover extra cog. Shifters and derailleurs are "dumb" and have no mechanical limit at 10. I'm led to believe that cassette(wheel), chain & reprogram are all that's needed! Maybe a 9070 main junction box as its the one "smart" piece...? But current e-tube hardware makes no distinction, so I think not.