Shimano Dura-Ace versus SRAM Red is a groupset head-to-head that’s been ongoing for over 15 years.
Now we've had plenty of time to experience the charms of the latest incarnations – 12-speed Shimano Dura-Ace Di2 and SRAM Red AXS – we’re ready to see how these flagship contenders match up.
SRAM launched Red to great fanfare in 2007, when it was crowned as the lightest mechanical groupset on the market.
Shimano came back with the beautiful but flawed 10-speed Dura-Ace 7900. SRAM then revamped Red, but Shimano took the lead with the launch of the Di2 7970 groupset – bringing electronic shifting for the first time.
In 2013, SRAM was first to go 11-speed with Red 22, then Shimano responded, revamping its Di2 system at the same time.
It took SRAM until 2015 to respond with eTap, which brought wireless electronic shifting, and both brands added hydraulic disc brake options soon after.
Shimano’s current 12-speed Dura-Ace Di2 (released in late 2022 and known as R9200) brought the improved ergonomics and brake feel from GRX Di2, while making the groupset semi-wireless and improving shift speeds.
As things stood, it had the advantage over SRAM, with a wireless front end well suited to modern integrated framesets, superior braking and better shifting.
SRAM has responded with the latest generation of Red AXS – lighter than ever, with improved ergonomics and braking, and added functionality you could say has been lifted from Shimano’s playbook.
Which one comes out on top in this long-running saga? Let’s find out.
Setup: wireless vs semi-wireless
Both Dura-Ace Di2 and Red AXS are easy to install and set up, especially compared to wired or mechanical systems on modern integrated frame designs.
Thanks to its semi-wireless design, Shimano’s system only requires the installation of wires to connect the front and rear derailleurs to a central battery, located in the seatpost or down tube.
Looping the wire around the bottom bracket can be tricky, and specifying the correct wire lengths (the SD300 wire is available in lengths between 150 and 1,600mm) to connect to each derailleur is an extra step in the process.
The levers pair to the rear derailleur (in which the brains of the system are held), though. In turn, these control the derailleurs. They are powered by coin cell batteries.
With Red AXS, in contrast, it’s simply a case of bolting both derailleurs in place, charging and clipping on the external batteries, then pairing them to the shifters and setting up via the AXS app.
Of course, both derailleurs for each groupset require aligning properly for installation.
In the past, the Red AXS front derailleur setup was somewhat tricky to get spot-on, but this has been much improved thanks to a new setup guide tool.
This clicks into the crankset, once installed, and gives a guide for the gap between the derailleur cage and chainring, holding the derailleur in place while you torque the bolt tight.
Both groupsets make good use of their respective apps (more on this in a moment) in allocating functionality, updates and adjustments.
When I pitted the latest-generation Shimano Ultegra Di2 R8100 against SRAM Force AXS, I remarked on a few things that still apply here.
The Shimano derailleurs, powered by one central battery, arguably look a little sleeker than SRAM’s enduring modular battery design, but I think this is more than cancelled out by the convenience of being able to switch AXS batteries easily.
It’s hard to directly compare battery-life times – Shimano’s central battery is said to last for around 1,000km, while SRAM says each AXS battery has enough juice for 60 hours of riding.
In reality, neither should prove a problem for even intensive users, with recharging these days a simple case of bike maintenance hygiene.
Overall, it’s fair to say that neither groupset should offer much of a challenge to a seasoned home mechanic, although SRAM’s fully wireless AXS system is the simplest of the two.
Winner: SRAM Red AXS
Connectivity and app
Shimano’s E-Tube app has evolved to be far superior to its early versions, with a much better user interface.
Now that Dura-Ace Di2 has Bluetooth (and ANT+) connectivity built into its rear derailleur, it’s easy to access the system and make changes through the app (previously, you needed the EW-WU111 D-fly unit to enable this connection, which wasn’t often supplied as standard).
Setting up the shifters and adding components (such as satellite shifters or a power meter) is simple to do, as is tweaking the indexing.
You can also turn on synchro or semi-synchro shifting modes. Here, the system takes care of front-derailleur shifting duties for you as you move through the block, or compensates the rear derailleur’s gear selection to the next effective ratio when you shift the front derailleur, respectively.
SRAM’s AXS app, however, still rules the roost here.
The user interface is cleaner, and alongside all the maintenance and setup functionality, you can also create multiple bike profiles within the AXS app (should you have more than one AXS-driven bike).
The AXS app also records a depth of information, which helps set it apart, including GPS, heart-rate and power data (which can be exported automatically to Strava), and metrics on shifting and time spent in each gear.
This now also links to the Hammerhead Karoo bike computer (which is bundled with the aftermarket groupset) creating a neat ecosystem – the bike profiles can be used as ride profiles.
The Karoo can also be used to alter the settings of the AXS system – blip-button functionality, the new bonus buttons on the shifters and shift protocols can all be adjusted from the head unit.
Winner: SRAM Red AXS
Shifting performance
Dura-Ace Di2 R9200 has been the king of shifting performance for some time now.
The combination of the smooth glide of the chain across the cassette at the rear and the fast, forceful shove of the front derailleur impressed the most, and SRAM’s previous Red eTap AXS drivetrain was left a little behind – even compared to Force AXS.
While still fast, Red eTap AXS’s front-derailleur shifting felt as though the chain was being gently coaxed between chainrings, which resulted in a comparatively hesitant sensation.
The new Red AXS front derailleur now feels as if it has the same urgency as its Dura-Ace Di2 counterpart. This is perhaps because the latest narrower cage pushes the chain sooner, and if you use the bonus button on the new lever hoods to actuate front shifts, it feels just as quick to move the chain in either direction.
The default shift logic of pressing both shifter buttons at the same time remains, if you prefer that – the bonus buttons are in a different location on the inside of the hoods, of course, so their positioning is only really suited to shifting from the hoods.
Shimano’s quiet and fast rear-derailleur action is at its best on Dura-Ace Di2 R9200, although Red AXS gets close to the same standard, especially when the chain is moving down the cassette.
Going the other way, the Red AXS shift speed is also impressive. By my reckoning, you can feel a little more feedback as the chain settles on each of the cassette's sprockets compared to Dura-Ace, but there’s little to choose between them.
Red AXS continues using a 10-tooth smallest sprocket. This gives a slightly rougher sensation through the pedals than Shimano’s smallest 11-tooth sprocket – but it’s a lot closer than ever before, while not many are likely to spend much time in this gear.
At launch, SRAM says it aimed to tackle this by adopting a larger lower pulley wheel on the rear derailleur, which reduces drivetrain friction slightly. In the absence of any other evidence, this seems a success.
As good as SRAM Red AXS shifting has become, though, Dura-Ace Di2 still has a slight edge overall.
Winner: Shimano Dura-Ace Di2 R9200
Gearing options and customisation
Shimano’s 4-bolt, 110 BCD (bolt circle diameter) design on its cranksets means plenty of scope for customisation using aftermarket chainrings.
Dura-Ace cranksets are available in 50/34, 52/36 and 54/40-tooth versions, and there’s a dual-sided power meter option. You can also opt for 160mm to 177.5mm crank lengths, in 2.5mm increments.
The 12-speed cassette (CS-R9200) comes in two options – 11-30 and 11-34 tooth. At launch, an 11-28t cassette was also mooted, but this has yet to appear.
SRAM’s options on Red AXS are far wider.
There are six 2x crankset options – 50/37, 48/35 and 46/33T come as OE equipment on complete bikes, and there are three more available aftermarket (larger, 52/39, 54/41 and 56/43T options, ostensibly for the strongest riders).
Unlike Dura-Ace Di2, Red AXS can also be had in a 1x specification, with five single-chainring options (42-50 tooth, in 2-tooth increments).
All are available with integrated spider-based power meters, with crank lengths ranging from 160mm to 175mm in 2.5mm increments, only falling short of Shimano’s longest 177.5mm crank option.
It’s worth remembering that SRAM’s chainring design is integrated – with the chainrings machined from one piece, replacing one requires both to be switched out. If you have a power meter version, this too must be replaced – at even greater expense.
While SRAM claims this aids crankset stiffness, the difference between Red AXS and Dura-Ace R9200 is negligible in reality.
At the back, Red AXS cassettes are available in 10-28, 10-30, 10-33 and 10-36t options – twice as many as Dura-Ace.
Though SRAM clearly has a broader range of options than Shimano here, some will prefer the slightly better mechanical efficiency of an 11-tooth sprocket offered by the Japanese brand.
Both systems support the use of satellite shifters. Shimano’s are wired plug-in units that run off the shifter batteries, whereas SRAM uses a wireless ‘blip’. These have sealed batteries, but SRAM quotes a 10-year lifespan, so it should be a while before these need to be replaced.
Red AXS can accommodate up to six in one setup (compared to Shimano’s two), but this is arguably overkill, even for time trialists.
Although many will opt for a full groupset when upgrading, it’s worth noting that SRAM Red AXS is also backward-compatible with all 12-speed AXS groupsets. This opens up a more economical pathway to upgrading – a component at a time, rather than a wholesale switch.
The majority of Shimano’s latest 12-speed Di2 parts are cross-compatible too, however backwards compatibility with its previous-generation, 11-speed groupsets is pretty much non-existent (chainrings are the only exception, but Shimano doesn’t recommend it).
While the integrated nature of the Red AXS chainrings and small 10t cassette sprocket might put some riders off, the wide-ranging options offered elevate SRAM Red AXS to a narrow, qualified win.
Winner: SRAM Red AXS
Braking
Shimano’s Servo Wave tech, brought in on the current generation of Dura-Ace, certainly gave it the upper hand over SRAM’s previous Red eTap AXS when it came to braking.
The ergonomic shape of the Dura-Ace lever, combined with the non-linear relationship between lever and caliper travel, means less force is needed to apply the brakes.
In practice, this results in the ability to scrub speed more effectively, while the feeling through the lever is excellent, and has been a standard-setter (along with Ultegra Di2 R8100, which shares the same tech).
The spacing on the calipers is also greater (Shimano claims it's 10 per cent wider than on Dura-Ace Di2 R9170), and I’ve found this all but eliminates irritating rotor scrape in adverse conditions.
The latest-generation RT-CL900 rotors have an improved braking surface and are less prone to warping, further improving the experience.
It’s here where the old SRAM Red eTap AXS noticeably lagged behind Dura-Ace Di2 R9200 – while you had all the power you’d ever need, the modulation and all-important feel through the lever felt less refined and more ‘on-off’. For new Red AXS, though, it’s a different story.
The brake-lever design is very different, with a horizontal piston arrangement that has enabled SRAM to repackage the innards and raise the pivot of the lever much higher.
The hoods are slimmed down to near-enough Dura-Ace size, and there’s a shaped depression in the top third of the lever designed to offer a spot for fingertips to rest on when resting on the hoods.
The lever has also been reprofiled, now gently kinking outwards, which helps make it easier to grasp from the drops.
SRAM claims the effort to actuate the lever is reduced by 33 per cent in the drops and 80 per cent less from the hoods (on launch, it claimed 20 per cent, but has since amended that figure).
It’s fair to say the old Red eTap AXS design, mainly due to the low pivot point, didn’t allow much lever movement from the hoods at all – but that’s all changed here. Single-finger braking from the hoods is possible, although how many people will prefer this over using two or more fingers is up for debate.
At the caliper end, the machined two-piece body sees the compressing piston moved more outboard (relative to the previous groupset), which is claimed to better centralise the pressure of the pads on the rotor.
In use, Red AXS braking feels just as good as Dura-Ace Di2 R9200, exhibiting a similar silkiness from the drops.
From the hoods, I think the Red AXS ergonomics have the beating of its rival, although ergonomics aren’t one-size-fits-all, of course – you may simply prefer how Dura-Ace levers are shaped.
Like Dura-Ace, it takes very little effort to induce accurate braking and subtle speed reductions, and the feeling through the lever is a broad match.
The SRAM Red AXS brakes offer four-point contact adjustment, whereby the calipers can be adjusted to close the pads earlier (or later) on the rotors. Reach adjustment (how far the lever rests away from the bar) is also on offer.
Dura-Ace, meanwhile, offers both reach and free-stroke adjustment – the latter is similar to contact-point adjustment, although rather than moving the pad, this adjusts how much the lever moves before the brake calipers move in response.
In reality, both now have plenty of scope for adjustment to suit most (if not all) hand shapes and sizes, and braking preferences.
While the latest Red AXS rotors have seen a small tweak to the alloy carrier to save a few grams, the brake track itself has remained the same – as has the pad material.
I haven't heard any brake squealing – a known issue with the previous Red eTap AXS brakes when wet – so far, although further testing with more poor-weather rides will help to certify this.
It’s worth noting that Shimano continues to use mineral oil for its road bike groupset brake fluid, while SRAM uses DOT fluid for Red AXS.
Winner: Draw
Weight
A groupset’s weight will, of course, depend on the specification you choose. Smaller cranksets (or 1x systems, with no front derailleur or second chainring) and cassettes will, naturally, be lighter, while Shimano and SRAM don’t make like-for-like matches. We compared weights earlier in the year when unboxing the latest Red AXS.
That said, both are impressively lightweight, as you’d expect of a professional-level groupset.
Dura-Ace Di2 R9200, with a 52/36T, power-meter equipped crankset and 11-34t cassette, weighed in at 2,579g. That’s 76g heavier than the claimed total weight at launch (which was for a non power-meter 52/36T crankset and an 11-30t cassette).
Our SRAM Red AXS groupset weighs in lighter, at 2,548g, accounting for a 46/33T power-meter equipped crankset and 10-33t cassette. That’s 52g more than SRAM’s claimed weight for Red AXS in its lightest 2x configuration with a 46/35T crankset and 10-28t cassette.
On paper, SRAM wins this one by 31g, with our groupsets put side by side, which is about the same weight as a slice of bread.
I can’t think of an occasion where this should be the deciding factor when choosing between the two. Even hill climbers will probably opt for even lighter, more specialist setups than offered by Shimano or SRAM here.
Winner: Technically, SRAM Red AXS – but a draw is the fairest conclusion
Aesthetics
Beauty is in the eye of the beholder, and while Dura-Ace has a clean aesthetic with its glossy black finish across all of its components, it could be described as boring.
My colleague Simon von Bromley, in his review of Dura-Ace Di2 R9200, said as much, and pointed out that a flagship groupset should stand out and look premium – like Dura-Ace 7900, which I (and many others) felt was a stunning-looking groupset.
The glossy finish on the latest chainset can be dulled by the rub of a shoe (especially a winter overshoe or boot) and I’ve found some of the sharper edges on the rear derailleur body can be prone to chipping and scuffing too.
In contrast, Red AXS has a bit of ‘bling’ about it (just like its predecessor, it’s fair to say).
The crankset’s silver accents are a clear statement and have been sharpened a little this time out.
The chrome logos are more subtle, although not as subtle as the Force AXS graphics, even with their rainbow reflectivity, but I think they unify well with the machined outer chainring.
The chrome-like finish of the chain is neat too (you can have a rainbow oil-slick colour for this and the cassette, if you so choose), as are the carbon crank arms and levers.
The calipers’ ‘skeletal’ brake bodies are also a marked improvement on the previous, chunky-looking silver calipers.
The one oversight might be the matt-textured front derailleur, which looks at odds with the sharp looks elsewhere.
I can understand the point of view that Shimano’s centralised battery design means its derailleurs are more svelte than its SRAM Red AXS rivals when the AXS battery units are installed.
If that’s a deal-breaker for you, Shimano will likely win the argument here. However, the Red AXS groupset, overall, remains far more striking – and how many of us lust after a top-end groupset that you could easily miss in a crowd?
Winner: SRAM Red AXS
Price
It looks like a surefire win for Dura-Ace Di2 R9200 when comparing UK prices, although the reverse is true for US-based riders.
Our complete Dura-Ace groupset is priced at £4,243.89 / $5,045.87, whereas our Red AXS setup comes to £4,590 / $4,590.
Things are also skewed slightly by the fact that SRAM’s price includes the latest Hammerhead Karoo bike computer. If you aren’t wedded to another bike computer brand, this adds tangible value.
Of course, real-world prices of groupsets vary wildly, so it’s worth seeing how much retailers end up selling them for.
On complete bikes, Shimano draws ahead. For example, a Specialized S-Works Tarmac is £12,000 / $14,000 with Dura-Ace Di2 (and a 4iiii Precision Pro dual-sided power meter, rather than Shimano’s own R9200-P crankset). Meanwhile, the limited-edition S-Works Tarmac Red AXS bike is £12,500 / $15,000 (including the power meter crankset, Hammerhead Karoo computer and a K-Edge cockpit mount for it).
The standard Red AXS bike previously was priced the same at £12,000 / $14,000.
Factor’s Ostro VAM with Dura-Ace Di2 R9200 is $11,149; the same bike with Red AXS and a power meter is $11,499.
Wilier’s Filante SLR is €12,500 with Red AXS and the power meter included; the Dura-Ace Di2 R9200 model costs €11,300 without a power meter.
Winner: Shimano Dura-Ace Di2 R9200
The winner: SRAM Red AXS
From our eight categories, we have a new victor: SRAM Red AXS wins 5-3.
That said, it’s incredibly close between the two groupsets, and a specific preference here or there could easily swing it back to Dura-Ace for you.
I fully expect Shimano to come back fighting, though, because those 13-speed, wireless patents seem to suggest the Japanese brand doesn’t intend on standing still.
However, as things are, Red AXS looks to be a deserving – if marginal – winner.
