As I know, Shimano Di2 R671 TT shifter can be used with both 9070 series and 6770 series.

However, my friend told me that the firmware of the rear mech, front mech and the other Di2 device should be in the same version. Otherwise, it can not be operated.

Therefore, I would like to ask wether the firmware version of R671 TT shifter is old version or latest version. If it is the old version, it will match my own 6770 rear mech and front mech in my road bike perfectly (will be put on the new TT bike). If it is the new version, I need to find a way to update my Di2 groupset....

Thanks a lot.

I can't see why. The button just tells the RD or FD to shift, if it is already at its inner or outer limit it simply does not shift.

SW-R671 can be used with either 6770 or 9070.

The shifter itself does not house the firmware; the battery mount and derailleurs do.

What your friend was referring to is the fact that to use 9070 FD and RD with 6770 drop-bar shifters, you would need to update your bike's firmware to the latest version which includes the programmable multi-shift function for the 6770 or 9070 RD.

Also, unless you plan on plugging the SWR671s into your 6770 shifters, you'll need to get the new junction box SMEW90A/B for a true TT setup.

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Turn down the suck knob.

Ok, thanks

That's means if I want to put my road bike 6770 Group with internal cable junction box to TT bike, I just need to buy a pair of R671 shifter and the time trial junction box, isn't it?

However, can the group operate without 11 speeds Di2 brake lever? (the brake lever is very expensive...)thanks

And next to impossible to get hold of.

I have recently done as you wish to, R671 shifters with Ui2 6770 mechs.

a) you don't ned the combo brake levers, I have the 3 port junction box and the TT shifters only
b) you do need to firmware update. The entire group was brand new to me in Jan 13 (although I do not know the manufacturing date of fr & rr mechs) I plugged it all together and it did not work, (fortunately I had ordered the upgrade box so that I could reprogramme shift buttons etc.), I then plugged in the components to upgrade firmware and only when everything had been updated did it all work together, i.e. fr & rr mechs, and shifters all needed the latest firmware. Battery got a boost at the same time and reprogrammed to fastest shift possible.

S

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Firefly FF050
Felt B2Pro
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Thanks

However, I would like to know more but the Di2 brake lever and the junction box.

You are using 3 pot junction box and without Di2 brake lever. If I will buy a pair of Di2 brake lever in the future, but now I temporary will use normal brake lever with Di2 TT shifter, which junction box I should buy now?

i recently installed the r671 tt shifters using the RD,FD, rear junction box from an older road U Di2 group and it worked without problem.
I even used the front junction A from the older 2012 road group. All i did was buy an additional internal rear junction B. so the front junction A plugs into the internal junction B at the STEM (to substitute the newer 3 or 5 hole junction A), then plug the R671 into the internal junction B at the STEM.
Hope this is clear. So the whole system has TWO junction B and 1 junction A to work, instead of 1 junction B and 1 new 3or5 hole junction A.