DI2 help

[oliver1850]

I have no experience with the stuff and am in the dark. Had to drive 15 miles and pick up a pair of German tourists today, one who had snagged a stick and destroyed his rear derailleur. It's Ultegra and I assumed it was 11 speed but stupidly did not check the model number of the RD. After checking I find that Shimano has 12 speed Ultegra which I didn't know existed, would have checked the model number if I had known. He needs a GS cage because he has a 34 large cog. Are 11/12 RDs functionally equivalent? We are going to be looking for whatever works and is locally available.

[zmalwo]

GS cage and 34t - sounds like he's got a R8050 GS cage rear derailleur. they aren't that expensive on eBay I think.

[TerryDi2]

Yeah... probably RD-R8050-GS.

If so, all of these are compatible:

• RD-6870-GS (SS would work too... but that's that small cage)
• RD-9070 (small cage)
• RD-R8050-GS (and SS, but that's the small cage)
• RD-R9150 (small cage)
• RD-RX815 (GRX, but compatible)

Note that the 'M' family will not work (M8050, M9050), and 6770 and 7970 also won't work.

Also... R8150 and R9250 are 12-speed Di2, which is not compatible with 11-speed Di2

[rice rocket]

oops Terry (aka Di2 Master) beat me to it.

No 11 and 12 speed components can work with each other, other than some satellite shifters, while all 10 and 11 speed should work with each other provided you adapt for the change in wire diameter if necessary.

Shimano keeps a comprehensive list:

[oliver1850]

Thanks for the replies. Turns out that he had a 6870, so at least there are some other 11 speed options.

[oliver1850]

I was somewhat surprised to find two 8050 GS RDs in stock at shops within 50 miles. Received great same day service from former Jelly Belly pro rider Bryce Mead at his shop in Sterling IL. The German tourists are set to head out tomorrow for Quad Cities, Omaha, and ultimately San Francisco.

Thanks again for giving me some insight into my first exposure to electronic shifting.

[robt57]

Originally Posted by oliver1850

I was somewhat surprised to find two 8050 GS RDs in stock at shops within 50 miles.

Well, when the RD does not shift to the smaller cogs when in the small front chainring with the RD-8050.. that is normal and not something wrong so you know.

It is possible also if the 6870 pieces have not had firmware updated for a lot of versions the 8050 may not play happy or at all possibly.

The battery firmware if old and the 8050 together... You did not say external battery or not...

running the eTube software if early external battery is different than with the A junction with the charger port in it etc.

[oliver1850]

Originally Posted by robt57

Well, when the RD does not shift to the smaller cogs when in the small front chainring with the RD-8050.. that is normal and not something wrong so you know.

It is possible also if the 6870 pieces have not had firmware updated for a lot of versions the 8050 may not play happy or at all possibly.

The battery firmware if old and the 8050 together... You did not say external battery or not...

running the eTube software if early external battery is different than with the A junction with the charger port in it etc.

When I called to check their stock Mead's said that it would need an update. That was why I hauled the bike 35 miles to the shop instead of attempting to set it up myself. Given this experience I am glad that I have stuck with cable operated drivetrains for my own bikes, and certainly wouldn't recommend electronic systems or modern carbon frames for touring.

[robt57]

Originally Posted by oliver1850

When I called to check their stock Mead's said that it would need an update. That was why I hauled the bike 35 miles to the shop instead of attempting to set it up myself. Given this experience I am glad that I have stuck with cable operated drivetrains for my own bikes, and certainly wouldn't recommend electronic systems or modern carbon frames for touring.

Honestly, is it really different than not knowing a campy cable end is smaller and using a Shimano cable on an ergo shifter. Minute example of course. But when that get done, it was because someone did not know the tech, right?

BTW, I have 2 old lap tops off the net I use for stopping e-tube from updating [each has an early and earlier version] for some mixes of early and mid age di2 stuff.

[Keith A]

Originally Posted by robt57

Honestly, is it really different than not knowing a campy cable end is smaller and using a Shimano cable on an ergo shifter. Minute example of course. But when that get done, it was because someone did not know the tech, right?

BTW, I have 2 old lap tops off the net I use for stopping e-tube from updating [each has an early and earlier version] for some mixes of early and mid age di2 stuff.

I’m a Di2 novice and am curious why an older version of their software is better?