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Inspired by the recent disc brake release really. However, I was reading that they're an 11 speed shifter.
What makes them 11 speed? Surely, it's just an up and down button with nothing in there that makes it 11 speed?
Where's the "brain" in electronic shifting? The bit that says how much for each button press and when to stop?
Have people started "hacking" these yet? Surely a bit of software tinkering could make it 9 speed or any speed you want.
Or am I mad?
Just lie down Onzadog,the nurse will be along with your injection shortly.
They are 10 speed compatible as well (with a firm wear change).
What about the front mech? Double only?
My next road bike will have Di2 just 'cos I hate derailleurs and their sporadic rubbing/out of sync bullshit that much.
I'd be happy to stay mechanical but with hydro discs, that means sram over Shimano.
I imagine you could hack the firmware to make them compatible, aren't the 11 speed ones ok on 10? I've a feeling I've read that...
speeds on Di2 stuff is set by the rear mech, so if you want 10 speed you would use the old Ultegra mech and matching front mech (apparently the fancy auto trim feature only works if it matches rear mech).
at least thats what was said on another forum.
The new 11 speed shifters will work with older 10 speed rear mech. The shifters are sending an up or down signal to the mech. The shifter has no knowledge of the position of the rear mech. The rear mech manages the autotrim for the front mech and I'd be very surprised if you needed to match the F&R mechs but I couldn't say 100%.
I'd be very surprised if you needed to match the F&R mechs but I couldn't say 100%.
The blurb on road.cc says you do, no concrete evidence tho, it sounded a bit like regurgitated sales blurb.
The shifter has no knowledge of the position of the rear mech.
I'm not entirely sure that's true. I think once the shifter places a shift command out on the bus, the mech will respond with what sprocket position it's at. Whether the shifter makes any use of this data is a different matter though.
I'm not entirely sure that's true. I think once the shifter places a shift command out on the bus, the mech will respond with what sprocket position it's at. Whether the shifter makes any use of this data is a different matter though.
Interesting, the thing is, I'm not convinced that the rear mech even knows what gear it's in! If you use the micro adjust to shift the chain to a larger sprocket (without actually shifting the mech using the button), I think you can still run through all the gears until the mech hits the limiters. This would lead me to believe the shifter just shifts either up or down until it hits the stops. I messed around with this a while ago and can't say for sure this was the case but I might try it tomorrow.
Actually, thinking more on this, I suspect the rear mech must know roughly where it is in order to work the auto trim......
I just had an email from my Shimano guy in Japan....
For the OP, the new Ultegra shifter with hydraulic cylinder (ST-R785) is compatible with ALL e-tube drivetrains, so Dura Ace 9070, Ultegra 6870 and 6770, as well as Alfine Di2. 10 speed or 11 speed. You *may* need to upgrade the firmware to make all this work.
[i]My next road bike will have Di2 just 'cos I hate derailleurs[/i]
Er, no derailleurs with Di2 then?
Well done on the dumbest selective quoting ever.
Actually, thinking more on this, I suspect the rear mech must know roughly where it is in order to work the auto trim......
As it happens I've got the electronic guts of an ultegra rear mech sat in front of me 🙂 I bought a 2nd hand one off ebay so as to find out what's in it.
Looks like there's one method of establishing position - a potentiometer on the output shaft, and another method for establishing the rate of movement and possibly fine scale movement - an optical shaft encoder near the motor.