The all-new Di2 components of the new Shimano Dura-Ace R9100 series have been making their way out to pro peloton in fits and spurts over the last few weeks. We’ve seen it pop up in a few different configurations at the  Tour Down Under, and also spotted it on some bikes while European teams have spent the last couple of weeks training in Spain. We had a chance to dig out some components from the spare parts bin in the bowels of Shimano’s service course in Calpe this week and have the real world weights for the electronic Di2 bits to complement the mechanical weights we got at US CX Nats

Now that there are essentially four Dura-Ace groups within the new R9100 series, it’ll take a decent spreadsheet and a bit of adding pieces together to get all of the different possible weight combinations. Here we are going to focus on the Di2 components, so we’ll see what is different than the mechanic items we looked at a week ago. For a comprehensive look at each combination, have a look at our previous coverage, for example when pricing was announced.

The heart of the Di2 drivetrain is the derailleurs. The R9150 rear weighs in at 197g & the front at 101g. That’s an extra 38g & 31g heavier than their mechanical counterparts with the addition of the servo motors.

The matching R9150 shift/brake levers to operate the 160g traditional rim brakes weigh in at 113g a piece. Their construction is identical with the same (mirror-image) internals so no weight differences to be expected from one side Di2 lever to the other.

While the derailleurs add up to and extra 69g over their mechanical counterparts, the pair of Di2 levers save you 144g making even the weight of the 51g internal battery and the few extra grams for the new inline D-Fly wireless unit & internal junction box pretty close to even.

Jumping over to the R9170 components to add in disc brakes, each of the hydraulic Di2 shift/brake levers weighed 158g, adding 45g over the rim brake version. But the new Dura-Ace flat mount disc caliper is just 138g, 22g lighter than the rim brake, not figuring in cable housing/wire or hydraulic oil.

Then you’ll have to factor in the weights for the rotors (not pictured). Weights for new RT900 rotors we’ve seen have been pretty much on par with the previous generation XTR Freeza rotors at 90g for the 140mm version and 14og for the 160mm rotors.

We already got a look at a 629g complete crankset with a semi-compact set of rings installed, but this 142g set of standard road 53/39 rings (without the 4 alloy bolts) can give us an idea of those bare crank arms weighing about 490g.

The other bits left out here – the 213g 11-30 cassette, 64g bottom bracket, and the wiring harness itself will add up to your complete Dura-Ace R9100 series build.

Hop back to the full tech story from our launch coverage of the group back in the summer, full pricing details, close up looks at the power meter crankset and new wheels. Stay tuned for our first ride impressions of the new Di2 version with rim and disc brakes, plus the power meter in the next couple of weeks! &


  1. will on

    Or even better, a Shimano 1x road group, especially at 105 pricepoint. I know you can make it happen with Wolftooth adapters, but let’s get with it Shimano!

    • lop on

      1x road is a gimmick that isn’t going to catch on, but Shimano is burying their head in the sand pretending that the gravel, cyclocross and touring markets don’t want things lke “road”-compatible clutch-type derailleurs and sub-compact cranks. I have no idea when they are going to wake up to this.

    • glenny oc on

      I’ve used the di2 disc and mechanical non group models and the shifting is flawless but I don’t see weight savings just a slight benefit to adjustability.

  2. .: r|b :. on

    The fact that half a year after the announcement the new Di2 parts are only trickling out to the point that even the pros can’t have the full groupset is laughable.

    Just received the new L/R bar top climbing shifters and to be honest they’re no better than my DYI splice job I did with the sprint shifters from the 9050 gen. Theres a plate for it to sit with the curve of the bar better but it’s still designed to use 4 zip ties to secure to bar. C’mon Shimano, Really?

  3. glenny oc on

    Just looking at the caliper weights it looks to me that the weight is a couple of grsms less than my br765 and 805 non group set. I expect more tbh Shimano at these prices. Where are the exotic materials? Pro will be expecting composite and titanium and it’s all available.


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