IrrelevantD wrote:So this kinda goes back to what others have said, but what does Di2 see you're rings as? We know that 53/42 rings work on the 7970, I can attest to 50/36 working on 6870. But as others have said, if you're running (or have Di2 configured as) 52/36, 50/34, etc, you probably won't be able to.
Do you have the Ant+/Bluetooth transmitter or the PC interface so you can go in and change the settings?
6870 allows full cross chaining on 52/36.
Don't know for sure about 8070, but I heard that it defaults to no cross chaining, but one can configure it (via Etube) to allow full cross chaining.
It's interesting that SRAM has a very different view on cross chaining than Shimano:
"At SRAM we love big-big. Amongst mechanics on the NORBA and Mountain Bike World Cup circuit (many years ago!), we called big-big the 'pro gearâ€™, because professionals would ride it all the time, no matter what their mechanics told them. The same applies to pro road racers. They'll stay on the big ring as long as possible [...] So we would encourage your readers to ride big-big if they like, as long as they donâ€™t experience chain rasp on the front derailleur cage."
http://road.cc/content/feature/213468-c ... ly-all-bad