SRAM Force AXS vs Shimano Ultegra Di2

Are there any users here who have first hand experience with both Shimano Ultegra Di2 R8150 and SRAM Force eTap AXS (both 12 speed, latest version)?

I am contemplating getting the new Canyon Aeroad CF SLX 8, and these bikes come in two builds that are identical in all aspects except the groupsets, aesthetics (which the Shimano version wins), powermeter (the Shimano build has 4iiii while SRAM has their own Quarq), and the price (the SRAM version is marginally cheaper).

The Shimano version is reportedly 300 grams lighter, but the 300 grams will according to BestBikeSplit save me perhaps 10-20 seconds up the Alpe d’Huez, 10 seconds on a 90 km undulating course I often ride or 2 minutes across the Tour des Stations (240 km with 9,000 ascent metres). In other words, the weight savings/gain is at best marginal, and the price difference is also negligible.

So that leaves me with a question that may be of interest to many other readers: Given that you have experience with the groupsets, which one would you go for and why? Any and all relevant arguments are much appreciated!

Get the red bike.



I’ve had the same debate on the exact same bikes. I’ve come up with 2 answers.

Team Shimano since it appears that replacement parts or making any changes to the groupset is more cost effective all else being equal (no idea if this is actually true).

But my real answer is … which ever bike becomes bike of week first and becomes 10% off.


Sram is 2watts slower due to chain. Sram power meter is better then shimano in everyway.

I am not sure if quarq sells a dzero for 12s

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Some people like the hoods better from one brand. But it‘s a personal thing and depends on anatomy (try it if you can).

I have Sram Rival and had Ultegra di2 (borrowed bike) and couldn‘t care less about the differences.

If you have a front shifter with Sram and one battery is dead, you can switch them. :man_shrugging:

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I ride both, Shimano is far superior in every way - shift quality, shift speed, shifting under load, battery life, hood shape, you name it.


I’m almost certain that 12spd shimano uses the same mounting points as 11spd so dzero should work for 12spd also. It may not match up aesthetically as well though.


I work in a bike shop, and while I haven’t ridden the Canyons, I’ve ridden a lot of groupsets in the last few weeks…

In terms of non-biased facts, the Shimano is more efficient than the SRAM, mostly due to the SRAM flat top chain and the 10t cog. So, if you’re concerned with gaining every small advantage, that may be good to consider. However, the Shimano powermeter is a joke, and everyone knows it. I would not trust anything that thing spits out, it’s accurate about as often as a broken wristwatch.

In my personal opinion, I’d go with Shimano and get a third party PM if you have the cash. The Shimano shifts faster and “better” (again, personal opinion), and I just enjoy the “feel” more. I’ve had both SRAM RED and Shimano Dura Ace on my bikes, and I’ll always choose Shimano from now on.

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OP said the Shimano build had a 4iii power meter. There are no major issues with those. If you have a Garmin bike computer, Shimano Di2 allows you to control the screens from buttons on the hoods. As others have mentioned, testing has shown Shimano chains to be more efficient probably saving you more time than the weight savings.

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Correct. Courtesy of powermetercity:

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Overall, I think my post in this thread is still up to date and covers pretty much all points.


  • Both are great groupsets.
  • Do not waste money on a Shimano power meter.(*)
  • Ergonomics (hood shape, buttons, etc.) >> features. Subjectively SRAM wins by a kilometer, even though I came from Shimano mechanical, I kept on mis shifting even after two weeks on a Di2 loaner. 0 mis shifts with SRAM. And I vastly prefer the hood shape.
  • SRAM has more and more flexible gearing options.
  • The 10-tooth cog (lower efficiency, blablabla) does not matter in practice, especially for us amateurs. It is fine.
  • Other features such as shift speeds or “shift quality” do not matter in practice.

(*) Even if you go for a Shimano groupset, get a Quarq Red-level crank, a Quarq power meter that mounts Shimano chainrings and use that. Rotor cranks are a great alternative. Or use Assioma pedals.

Edit: @Power13 has me beat, yes, get the red bike. Red bikes are the second fastest, they are only beaten by yellow bikes. :grin:

I don’t think that’s universally correct, pricing depends on where you live. I live in Shimano land (aka Japan), so we actually pay more for Shimano gear than if I were to order it off of bike24 or so. One factor to consider is that SRAM gear is less common, so you might not be able to walk into a LBS and pick up a pair of brake pads for your brakes. But if you order online, pricing and availability are comparable in many markets.


sure but a Red crank with power meter gives you no options on the crank. And then there is this:

In a perfect world I’d have stuck with Shimano, it does feel like it shifts faster and although practically it doesn’t matter, sometimes the shifts are slightly delayed and thats annoying.

I don’t think your sentence makes logical sense. (Maybe you hit reply too soon, happens to everyone.)

What do you mean? Did you mean that going for Red cranks gives you no options on chainrings? The Red, old Force and Quarq D1/D2 cranks are compatible with Quarq’s DFour power meter, which mounts Shimano chainrings. Officially, it is compatible with 11-speed chainrings, but as @mhandwerk pointed out, they seem to be compatible with 12-speed chainrings, too.

I mentioned efficiency (“the 10-tooth cog”) and shift speeds. Like I wrote, I think neither matter in practice.

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They’re both excellent groupsets. I think that red and purple looks awful, but I have 2 black bikes and a matte orange bike, so what the heck do I know anyway!?

Pros for shimano - like the shifter shape better, so much easier to bleed brakes. I like the brake feel better.
Con for shimano - I find it hard to feel the 2 different buttons when wearing thick winter gloves, so I have my di2 shifters setup sram style, with the right hand moving both FD and RD outboard, left inboard

Pros for sram - shifting is much more intuitive to me. In house power meter still regarded as one of the best
Con - brake bleeds are a pain in the ass, small chainrings are weird to me, even if it’s technically a bigger gear with the 10 tooth

I swap wheels between my road and cx bike and had the road di2 first, so I went shimano on the cx bike with same size rotors to make the swap effortless.

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Some purples work, but I agree, this one ain’t it. I really like the purple the CAAD12 special edition came in.

And orange is a great color. I’m over black, there is too much black in the world. What’s the point of getting the equivalent of a sports car and pick a subdued color? :slight_smile:

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I personally prefer SRAM hoods and shifters. I find it much more intuitive. Every time I go from my SRAM bike to my Shimano one, I screw up a few Shimano shifts. It never happens the other way around. I must have the only one, but my Shimano front derailleur drops chains. Shimano does last longer, but SRAM is easier to charge, and in an emergency you can swap the batteries. Shimano brakes are better. Shimano replacement parts are far easier to get your hands on. Not a fan of the red and purple combo.


ok, highly limited and expensive options.

Want to swap from 46/33 to 50/37 or 48/35? Pull out the credit card its going to be expensive.

And what happened to the pro options (asking for a friend)? Biggest you can buy is either the Aero 1x TT option, or 50/37.

Some things I like about the SRAM Red AXS crank, but with integrated PM it aint cheap and aint very flexible.

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The compatibility chart you posted only pertains to SRAM groupsets, not Shimano.

Quark’s D1 crank is a relabeled Red crank. The D2 is a relabeled last-gen Force crank. Both are compatible with the DZero and DFour power meters. The two only differ by their chainring mounting options. The DZero is for SRAM chainrings and the DFour for Shimano 11-speed chainrings. But they also seem to be compatible with 12-speed chainrings. So I could mount the power meter and chainring combo that @mhandwerk posted directly to my Force cranks in lieu of my DZero power meter and 1x chainring.

You don’t need to go with SRAM 2x power meter chainrings. Not sure they anre even compatible with Shimano’s 12-speed groupsets.

I run SRAM with a HG chain. All the watts!

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Either I’m missing something, or you stopped talking about the 2x Red AXS crank with integrated PM and 8-bolt interface in my original post.

This is my crank, and retail pricing for chainrings ‘swaps’

Expensive and not flexible.