TiHabanero

Shimano got a few things right with their new 12 speed wireless. Increasing pad rotor clearance was a no brainer and I am happy to see it. Hope the other guys follow suite.
Going wireless, well almost wireless is another no brainer, and cleans up the hbar and install.
Keeping with more traditional chain ring options makes sense for the racing and I am happy to see it.
Avoiding the 10 tooth sprocket on the rear. Makes sense to me.

However the groupset is an almost winner from where I sit. Sticking to the centralized battery makes no sense. Copy SRAM, please! Don't copy their shift button choice, but the independent batteries make total sense and clean up the bike so nicely. No holes in frame required. No stringing wires thru chain stays and up the seat tube required. Installation is easy peasy. KISS.

Suppose we have to wait for another product cycle for Shimano to catch up. Kind of a let down.

Bald Paul

Supposedly, the wired connection between the battery, front derailleur, and rear derailleur make the shifts faster. Now, a few hundredths of a second may not make much difference to most of us, but if you're racing, it may.
The battery and derailleur wires aren't really the big issue with Di2, IMHO. It was wiring the handlebars, and bars to frame entry that was a pain.
Come to think of it, I wonder where the charge port for the Di2 battery will go? I use the bar end plug, but with no internal wiring from the bars to the battery.... hmm.

Oh, well, it's going to be awhile before I'd even consider 'upgrading'. "Awhile" being defined as when I hit the lottery. My current bike was paid for from settlement money resulting from getting hit by a car. I don't want to do that again, no matter how good the new system looks!

Koyote

Actually, removing the wires from the front end is kind of a non-issue. If you use the bar-end junction box, you have only one wire coming out from under the handlebar tap. If you wrap that single wire around a brake cable, it was practically invisible already. Sure, it was a little extra work in the setup, but that’s a one time thing.

While I agree that fewer ports and fewer wires is a good thing, I also like the single battery approach – – not much to keep track of, not much to forget.

chaadster

I dunno…that front shifting speed and accuracy looks unbelievable, and they say the big battery gives them the power to make it happen, so it may be a worthwhile trade-off. Arguably, if you don’t need ultimate shifting performance, you don’t need Dura Ace. But yeah, SRAM’s full wireless is the ideal made real in terms of installation ease, and personally, I find the performance of Force AXS satisfactory for my needs. I’d like DA performance levels, but the cost is prohibitive for me.

Now when Campy go full wireless, that’s what I’ll be in for!

Rogerogeroge

The charging port as well as the indicator light are in the rear derailleur.

spelger

from what i have read with this new RD you can shift under load with no hesitation in performance. that may have been a contributing factor in the design choice.

icemilkcoffee 

Can anyone explain why this would be the case? I mean, radio signal travels at the speed of light. I don't think you can get much faster than that.

Koyote

You know that line from the movie Spinal Tap? "This one goes to eleven."

Well, the new D/A goes to twelve.

unterhausen

I imagine they could use a bigger battery with more instantaneous current delivery. So more torque, and thus faster shifts

This system meets my need for a travel bike that splits at the top tube and down tube. But I'm not rich enough for it.

mstateglfr 

sram's wireless derailleurs are the fugliest derailleurs of all time. Ever.

Shimano doesnt need to catch up on this- in a deep dive interview, they flat out said they chose this route.

Racing Dan

Not having a battery on the derailleurs makes them lighter and much less bulky, and, judging by the previous generation, much cheaper too. Its only a few wires and its a one time deal and no maintenance like with mech cables. To me, all wireless feel like having batteries in the car tail light, cos you couldn't be bothered running a wire .. ;-) Imo, in device batteries are best suited for removable objects like the computer or lights that are only used occasionally.

TiHabanero

I work in a shop and the elimination of a wired system, in terms of the time it takes to build a bike or replace some components, is significant, and makes complete wireless something all the makers need to pursue.
I have also ridden both systems in 11 speed platforms and they both work exceptionally well and without hesitation. Both 11 speed systems shift under load without issue. The Hyperglide + may make it easier for the der to move the chain under load, but I have not seen a real need for it, yet.
I think it is safe to say that none of us on this forum makes a living racing a bicycle, therefore it is safe to say that debating .01 second difference in shift time is fruitless, and likely not an issue for the pros either, but makes a sound good benefit selling feature. Come to think of it, mechanical shifting works really really well. Do we need to go electronic at all?
Yes, we do when Campagnolo goes full on wireless!

Racing Dan

I think they should give an option for a dynamo. Say, in the the tension pulley. I calculated the average power consumption for the previous generation DI2 to be less than 0.1W. Way below significant for the average weekend warrior

Racing Dan

Honestly, the new wiring DI2 with wireless shifters, is bound to be much simpler than before and much simpler than mechanical. At worst its one battery, one junction box and the derailleurs. Id take that any day over the silly expensive and bulky SRAM DRs

Litespud

the charge port is in the RD itself. The RD is the heart of the system - the receiver for the wireless signal and the conduit of signaling to the FD (ie it’s the junction box), contains the system status LEDs. and the access to the battery. I suspect that replacing the RD after a prang will be a pricy proposition.

Litespud

it’s not the speed of the signal, it’s the extra grunt that the big battery can provide to the derailleurs.

unterhausen

The first Di2 system was for comfort bikes, and it did come with a rear hub dyno because they didn't trust a comfort bike user to charge a battery.
You will find the hubs on ebay sometimes.
But it was a fairly substantial dyno.

mschwett 

i've had my eye on an aethos for some time, and the new DA was the excuse i needed to finally pull the trigger and order one. unfortunately it'll be next year before i'm riding it lol.

GlennR

How many here race? Of those how many are sprinters? I don't think you do a lot of shifting if you're strong enough... unless the course is a real roller coaster.

If you didn't raise your hand the speed of shifting is insignificant.

If you like Shimano, you don't need to justify it. I've ridden both and I like Sram.

I'm sure the new Shimano 12 speed will be a big seller with many people upgrading for the sake of upgrading.

Racing Dan

Im betting that dynamo was for light as well? The battery in the current DI2 road line up is 3.7 Wh. Assuming it will work for 1000 km, as promised, and you go at an average of 30 km/h it can last about 33 hours. 3.7/33 gives an average of 0.11W. That could easily be covered with a tiny little dynamo, in, as suggested before, the tension pulley.

TiHabanero

It is well known in the circle of wrenches and sales people in our shops that I never recommend SRAM products to anyone, well almost never. The only item SRAM makes that I truly believe is well engineered is their wireless drive train components. They really are top notch and well thought out and well manufactured. Wireless shifting is the only product SRAM offers that I recommend over Shimano.
Not sure why Shimano is so married to a wired battery. Makes no sense other than it costs less, which makes no sense considering the cost of electronic shifting to begin with.
As far as shifting under load, once again both 11 speed systems seem to do it without a problem. Shimano claiming a single battery helps with this is blowing smoke up someone's rear end to justify why they do it. It ain't the truth.

DaveSSS 

Show me where the shimano derailleurs are sold for less than sram, at the same level. There is no third level shimano 12 electronic. The total battery weight is the same 50 grams. I like carrying a spare, so I'll never have a dead bike that needs charging. No wires is hard to beat.

Racing Dan

You can make up any number of reasons as to why components are or are not comparable or at "the same level", but a Force AXS read DR is about
2x the price of a ultegra R8050 DI2.

DaveSSS 

A sram red axs RD retails for $724. Shimano DA 12 retails for $815. Force costs $350 and rival axs is only $255. What an 11 speed shimano RD costs is irrelevant.

https://cyclingtips.com/2021/08/new-shimano-dura-ace-di2-r9200-and-ultegra-di2-r8100-everything-to-know/