Rumors have been consistent that the group will be semi-wireless, with both derailleurs wired to the same battery and wireless shifters. Of course we won't know for sure until the official announcement but I think semi is pretty likely.

This history innt entirely accurate. All 6770 10 speed Di2 components still work with successive generations of Di2 components. The only cross compatibility killed was mixing 10 and 11 speed front and rear derailleurs. Shimano claimed it was accidental in the firmware update and I can see that being true. They just said they wouldn’t reverse it because the trim function for each series was optimized. Shimano is always so conservative on performance specs that this shouldn’t be surprising.

So with the exception of the first gen DA Di2 Shimano has been very good about supporting older Di2 compatibility. The limitations on these newer components are going to be:

1.that they’ve always relied on the rear derailleurs setting the number of shift positions. I’d be pleasantly surprised if Shimano changes this approach and allowed firmware updates to change older RDs to support additional cogs.

2. The wireless shifting capability is apparently supported with transmitters in the shifters and a receiver in the RD. Seems like this setup won’t allow older Gen Di2 to support wireless shifting. Hopefully the all-wired options allow for swapping derailleurs to allow 12 speed cassette use.

There is a 300 page thread on WW and some of the later ones have a lot of patent drawings and pictures. They suggest:
1. DA cassette to be microspline only.
2. Ultegra to be HG with an adapter for microspline
3. All cassettes start at 11t
4. Junction box is inside the shift levers
5. Semi wireless with internal battery and derailleur connected by wires. Eliminates wires from the front of the bike to the back.
6. Hood is slightly larger, presumably due to larger fluid reservoir to improve piston retraction

I'm happy to see it will remain slim and sleek. Likely DA will maintain the ~150-250g advantage and aero advantages over AXS.

Btw, "semi wireless" is a stupid term here, given that even AXS has some wires for levers and junction. But I get we're going to run with that.

for tri, yes. road and gravel, no wires, unless you have secondary shifters on the road bars.

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Dan Empfield
aka Slowman

Wireless shifters: https://www.cyclingnews.com/...ess-patents-suggest/

Well I am afraid there are bigger drivetrain losses than aero gains, otherwise the Wattshop guys and UK TT crowd would on little rings, rather than the massive dinner plates they are currently riding.,

Shut it!

Does anyone know if this will work with my 9100 crank set? 12 speed means thinner chain, no? I'm looking forward to the TT version of this.

The width difference between a 10 and 11 spd chain is 0.5mm while the difference between a Shimanos 11 and 12 spd MTB chains is 0.2mm.

In my experience the tolerances on chains and chain rings didn’t cause an issue using ‘10 spd’ cranks with an 11 spd chain. A chain has to do a lot of bending to allow for the full range of I gears so you want the chain rings to be narrower than the chain. I expect the same is true of 11 to 12 speed given the small difference in chain width.

What I have no idea about is whether Shimano will have updated the ramp profile on the rings to improve shifting for the smaller chain. All the spy shots seem to include preproduction cranks making it hard to know if major changes are intended for the cranks.

I suspect something is a foot with power meters given what Shimano just did to Pioneer. I wouldn’t be surprised to see a substantial altered crank for 12 spd which better integrates an accurate power meter. Shimano doesn’t want that in the public eye yet though and has given riders alternatives for testing.

What’s the purpose of Microspline other than to accommodate a 10t cog?

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"They're made of latex, not nitroglycerin"

Microspline cassettes will cause people to buy new wheels.

Am I the only one that doesn't care about it being wireless? Please, give me wires. The few grams are not going to kill anyone, you get better battery life, and they just work.

And will we see 12 sp mechanical?

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***

This is the best thing ever cleaning up the front end getting from bars into the frame with no junctions or cables.

Many people seem to be running (and preferring) Shimano's 12sp chain on R9100. Reported to lasts longer (I think according to frictionfacts) and is much quieter (first hand reports in forums). So unless shimano comes out with a road specific chain that is different, it should work just fine.

Except you still have brake cables/hoses.

Yes I'm aware of that.

What garry p said...

Probably not the only one. But you have to admit that the front half of Di2 as it currently exists is a bit of a fluster cluck of wires, junctions, and modules. It may very well still be for tri bikes, especially if you want shifters at both hands positions. But for a standard road bike, a wireless front end would be eminently easier for installers, be they home mechanics retrofitting, or oems building bikes in volume.

SRAM eTap road shifters supposedly get 2 years or so out of a CR2032 disposable battery. A spare costs ~$1.00, weighs ~3 grams, and takes up roughly the same space in your flat kit as a quarter coin. That’s a very small compromise for the ease of install and servicing.

It’s the derailleur batteries with eTap that require a bigger compromise from the end user compared to Di2. Managing the charge level of two batteries with much less capacity can be more of a chore. Using eTap-like wireless brifters and a bigger battery like Di2 has for the derailleurs seems like using the best of both systems. Yes, you still have to run some internal wires in the frame. Depending how they do it, it could still be quite simple; no more complicated than cabling a mechanical shift bike with internal routing.

Check out videos 1 and 4 of the FSA K-Force WE installation tutorial. This is a hybrid system with wireless brifters and a common battery for the derailleurs.

https://www.fullspeedahead.com/...eld_type_value=video

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"They're made of latex, not nitroglycerin"

I am happy with semi-wireless as long as the shift speed stays the same, I have sram force on my gravel rig and ult di2 on my road bike and the difference in shift speed is small but obvious between the two.

I have Sram red etap on my road bike, Shimano Dura Ace DI2 on my tri bike, GRX DI2 on my gravel and I prefer the Sram rear myself. Sram front derailleurs have always been a POS in compared to Shimano since forever.

Someone on weight weenies posted a picture of the new Di2 wires, they use a different connector. More evidence of significant changes group to group and lack of interchangeability. While in theory the old system should be able to be programmed for a different cog I personally think the likelihood that Shimano will do that is low. Maybe someone will be able to hack the shifters or there will be an adapter for the new wiring but I'd be very surprised if cross-generation compatibility is officially approved and the only things you can carry over without a hack are crank arms and brake calipers.

On the other hand, rumors are that you will be able to use existing freehubs and wheels, that 12 speed Ultegra cassettes will use existing freehubs and only 12 speed D/A cassettes will need a microspline freehub. At least, that's the rumor...

I really hope that this time give us a 16-tooth ring in an 11-28 cassette.

When they went from 10 to 11 speed, I figured they'd finally would correct the one annoyance of a 10-speed 11-27: the lack of that 16 tooth ring. I cannot tell you how many times I've found myself shifting up and down looking for the right gear because it jumps from 15 to 17.

I figured, with 11-speed, they'd just add a 16-tooth ring in there, right? Nope. They changed it to 11-28 and still left out the 16. Grrr...

1000 times, yes!

1,001 times, yes!

Apparently you didn't read a few posts past that I'm the dame thread. No need to hack. There is an adapter made by Shimano that convert new connector to old. Already has a part number listed. It suggests planned interchangeability.

So this suggests that you’ll need new front and rear mechs instead of making them 12 speed with a firmware update. This also implies that you’ll be able to use the existing brake levers with the new calipers. Now I wonder how much of an update the calipers and rotors got. As the leak didn’t show the calipers at all and they appear to be using the xtr rotors