We put the new Shimano Dura-Ace R9100 electronic groupset head to head with SRAM Red eTap

With the launch of Dura-Ace R9100, Shimano has launched a new salvo in the battle of top-end electronic groupsets against SRAM eTap and Campagnolo EPS.

If you’re buying a new bike with electronic shifting in the next year, the likelihood is that it will be fitted with with either SRAM eTap or Shimano Di2, so we’ve put them head to head to see how they compare.

Ease of setup

Compared to mechanical groupsets, SRAM eTap and Di2 are both easy to set up. Although both still have high and low limit screws on the derailleurs, all of the rest of the set up is done using buttons on the derailleurs and the shifters, which makes micro-adjusting the shifting a particular doddle.

SRAM eTap is the easier of the two systems to set up initially, and should be well within the capabilities of anyone with a decent set of Allen keys and the ability to read an instruction manual.

Watch: how to install SRAM Red eTap

Our step-by-step installation guide will give you a full run-through of how to fit SRAM Red eTap, but it really is as simple as bolting on the derailleurs and lining up the gears using the function buttons on the shifters and the limit screws on the derailleurs.

Shimano Di2 has a slightly more complicated setup process. Bolting on and adjusting the derailleurs is done through a broadly similar process, however you also have to deal with the routing of the cables to connect the derailleurs, shifters, battery and junction box.

Although, setting up exactly how you want your Di2 to shift has gotten a whole lot easier with the introduction of the updated eTube app, which now works across phones and tablets.

It’s intuitive and you can easily pour hours into the setup getting the most out of your electronic gears.

It’s from here you can set up Synchro-shift, programme, the speed of shifts and change which shifters shift what. It can even let you transfer over your shifting setup to your other Di2 equipped bike, because obviously everyone has two…

Comparatively, SRAM’s eTap system is far more of a setup and go deal. Granted, a lot of riders out there will value it for just that, but it’s worth recognising the systems are very different, with Shimano striding ahead in terms of customisation.

Battery Life

If there’s one area where Di2 wins outright, it’s on battery life. The latest iteration of Shimano Dura-Ace Di2 should be good for 2000km on a full charge, which might be only two weeks riding if you’re making your way around France in July, but should be a good couple of months for the rest of us.

>>> Six things no one ever told you about Di2

Power for Di2 is provided by a single central battery which is usually located inside the frame. This is then recharged through a plug in the junction box, with charging only taking a few hours. The junction box also includes a light which gives an indication of the battery life when you hold down a shifter button for a couple of seconds.

Watch: buyer’s guide to road bike groupsets

SRAM eTap is powered in a different way, with the derailleurs having separate rechargeable batteries, while the shifters each have a CR2032 coin cell battery. Battery life is then indicated by a light on each component, which changes colour depending on how much juice you’ve got left.

>>> How to set up your brakes (video)

Although the SRAM shifters will last up to two years on a single battery, the derailleurs have a stated battery life of 60 hours or 1,000km, so roughly half that of Shimano Di2.

SRAM RED eTAP rear derailleur battery

The SRAM batteries can be removed from the derailleurs for charging

However, when the batteries do need charging, the process is nice and easy, with SRAM Red eTap coming with a charging dock which simply needs to be plugged into the mains, into which you put a removable battery from the derailleur which will be fully charged in an hour.


Dura-Ace R9100 comes with redesigned front and rear mechs with the latter now able to handle cassettes of up to 30 teeth. It’s telling that when Shimano explained to us why they do not see the need to update Dura-Ace to wireless shifting, they said that the feedback from the pros was that the shifting on Shimano Dura-Ace Di2 was so good that there was simply no point messing with it.

The new Shadow rear derailleur architecture, which is transferred over from Shimano’s MTB groupsets, ups the game still further on shifting quality, with the mech body positioned directly below the cassette rather than to its right for more precise shifting.

Where the new Di2, and indeed all electronic shifting systems (including eTap), stand out is with the front derailleur shifting. Having an electronic motor in the front derailleur gives a hell of a lot more power than you get with mechanical systems, which is a particularly good thing if you have small hands and struggle to properly reach the shifting levers.

Watch: SRAM Red eTap review

While mechanical systems can require a decent amount of force to be applied to the lever, particularly when shifting from the small ring to the big ring, with an electronic system you just need to give a quick press of a button applied with no more force than if you were shifting from the 12 to the 11 with the rear derailleur.

So if Di2 and eTap can’t be separated at the front, it’s at the rear derailleur where Di2 really sets itself apart.

>>> How to change your chain (video)

As you’d expect, the shifting is crisp and precise, but also seriously fast, so you can always be confident that you’ll quickly be able to find the right gear when it’s needed to respond to an unexpected attack.

Dura-Ace front and rear mechs are redesigned

Dura-Ace front and rear mechs are redesigned

Unfortunately, SRAM Red eTap can’t quite match Di2 at the rear derailleur. The shifts are just as accurate, but just a little bit on the sluggish side. Ok, to call them slow would be pushing it, as they’re still completed within half a second or so, but if it’s race performance that you’re after then you might hope for a little more.

>>> Are you using your bike’s gears efficiently?

SRAM has acknowledged this slow shift speed, saying that the decision was made to slow down the shifting speed in an effort to prolong battery life, but perhaps it could offer a firmware update to enable faster shifting for racers who would be prepared to sacrifice decent battery life.


New Di2 levers come in road and TT versions as well as satellite shifters

However SRAM eTap does claw back some ground with its intuitive shifting system. While the hand movements used to shift on Di2 are the same as with mechanical Shimano systems, SRAM has taken a completely new approach with eTap, using the right lever to shift up at the back, the left lever to shift down, and both together to change the front derailleur.

This can take a bit of getting used to, but is dead easy to use once you get the hang of it, even when wearing bulky winter gloves. The SRAM eTap shifters also give a bit more of a click when you’re shifting, meaning that you can always be sure that the button has been pressed and the signal has got through.

Dura-Ace R9100 now allows you to set up the shifters to work in a Synchronised Shifting mode.

A single shifter can be used to control up and down shifting, with the system determining when a gear change requires a shift of the chainrings as well as the cassette sprockets. There’s also a semi-synchronised mode in which the rear mech is automatically trimmed in response to the rider shifting chainrings, so that there’s not a large change in ratios.

This all goes some way to closing the gap with SRAM’s system.

>>> How to change your cassette (video)



shimano dura-ace r9100 groupset shifters

Shimano hits a homerun here with the updated R9150 Di2 system. The hoods have received a serious shrinking across all systems, including hydraulic – which previously was the biggest due to having to incorporate the master cylinder.

In comparison, the design of SRAM eTap HRD, SRAM’s flagship disc brake and electronic groupset, has been left behind a bit, with the hoods still coming in chunkier than the Shimano R9170 options.

Shimano has also caught up in terms of lever feel. Previously, it was a lot easier to miss shift, because the shifters were so closer together. Now though, Shimano has introduced a far more resonant click and chamfered lever edge to help differentiate the two.


With all of the non-electronic parts (i.e. the chainset, cassette, chain, brake calipers, and bottom bracket) being taken from SRAM Red, the world’s lightest groupset, it’s no surprise that SRAM Red eTap is more than 150g lighter than Shimano Dura-Ace Di2. In fact it’s the first electronic groupset to duck in below the 2kg barrier.

Watch: which climbs faster – a lightweight bike or an aero bike

However if you add up just the comparable electronic parts, then SRAM Red eTap totals 658g while Shimano Dura-Ace Di2 comes in 36g lighter. But on top of that you of course need cables and cable housing (and frame ports) for Dura-Ace but not for eTap.

SRAM Red eTap Shimano Dura-Ace Di2
Rear Derailleur 235g 204g
Front Derailleur 162g 104g
Shifters (pair) 261g 230g
Battery N/A 84g
Chainset 557g 609 – 621g (dependent on rings)
Cassette 151g 163g
Chain 246g 248g
Brake Calipers 240g 294g
Bottom Bracket 53g 67g
Total 1,905g 2,003g


Traditionally, Shimano Dura-Ace Di2 has been undercut by SRAM eTap, and nothing changes here with the Shimano R9150 system rocking in at £2,964 higher than eTap at £2,059.

In fact in terms of prices, SRAM eTap’s closest rival is Shimano’s new Ultegra R8050 groupset, which in our opinion is every bit as good as Shimano’s Dura-Ace model.

SRAM’s Red eTap HRD system also undercuts Shimano’s R9170, with the former retailing at £2,668 while Shimano’s comes in at £3,174.

This page was updated on Nov 1st, 2017 with the updated pricings for Shimano Dura-Ace.