Shimano’s new Ultegra Di2 electronic-only groupset delivers Dura-Ace performance for less cash

Hot on the heels of Shimano’s new flagship Dura-Ace Di2 launch comes Ultegra Di2 R8100.

Like Shimano Dura-Ace Di2 R9200, the new Ultegra road bike groupset is 12-speed, available with rim or disc brakes and semi-wireless (in the disc brake variation). Crucially, there's also no mechanical option for Shimano's new second-tier groupset.

As Shimano's top-tier groupset, Dura-Ace historically launches ahead of Ultegra, which then typically follows a year later. This time round, however, the Japanese firm is launching both groupsets at the same time.

As a result, the new Ultegra groupset series brings all the technical advantages of the latest 12-speed, semi-wireless pro-level Dura-Ace system at a more accessible price point. (The rim brake Ultegra Di2 groupset is still fully wired).

Ultegra Di2 isn't exactly an ‘every person’ groupset, but with current R8070-equipped bikes appearing from around £4,000 it’s in the realm of your serious cyclist, rather than the WorldTour-level price tags associated with Dura-Ace Di2.

We'll focus on Ultegra Di2 in this story. If you want to read about Shimano's crème de la crème, head to our news story and first ride impressions on the new Dura-Ace groupset.

Wireless, sort of

The new Ultegra R8100 is electronic-only and, in the disc brake version, wirelessly communicates gear-change inputs from the shifters while maintaining a wired connection from the rear derailleur and front derailleur to a battery mounted in the seat tube.

The previous battery won’t carry over to R8100 because Shimano has designed the new system around a smaller diameter wiring loom (SD-300).

It’s not the first time we’ve seen this configuration. Back in 2017, FSA’s K-Force W.E. (wireless electronic) group brought us a wireless shifter-derailleur interface and central battery solution. (SRAM, of course, has long offered its fully wireless eTap AXS groupsets.)

Shimano's system promises high-security and fast processing, with a low power consumption chip circuit and the same internals as Dura-Ace.

Power consumption is the main reason Shimano has persisted with the single, larger volume battery and tells us the new BT-DN300 battery should last for 1,000km between charges, while the coin-cell CR1632 batteries in the shifters should be good for 1.5 to 2 years of use.

Unlike current Di2 systems (you can read our Shimano Ultegra Di2 R8050/R8070 review), the new Ultegra charges direct from the rear mech, so no junction box is required when configuring a bike.

Alongside the charge port being added to the rear derailleur, the rear mech also gets a function button to allow you to switch between shifting modes (synchronised and semi-synchro) without the need to connect to Shimano’s E-Tube app.

Synchronised shifting means the most efficient chainring is automatically selected on the front derailleur in synchronisation with rear derailleur gear shifting, while semi-synchro is when the system automatically adjusts the gear on the rear cassette when a front shift is made.

Still, using the app will be a must if you want to get the most out of the groupset – and you no longer need a Bluetooth aerial fitted as an optional extra in order to get that functionality, as is the case with Shimano's existing Di2 groupsets.

This solves a bugbear of ours as the current Bluetooth unit costs in the region of £70 (and more if you need a bike shop to fit it), whereas SRAM's eTap and AXS groupsets have connectivity built-in as standard.

Anyway, the app will allow full custom options, such as multi-shift settings, STI button mapping (to assign the hidden buttons on the top of the hoods to control a Garmin, for instance) and use of third-party bike computer head units to display Di2 information (battery level, gear selection).

Plus, you’ll need the app to update firmware down the line without having to take your bike to a Shimano service centre.

If you’re opting for the rim-brake option, it’s worth noting that this system is still fully wired.

However, because the brains of the system are now in the rear mech, you don’t need to use a junction box mounted in the frame (or under the stem), you can just run wires down to the bottom bracket junction. So even with the "old-school" Ultegra Di2 option, a rim brake bike should still look cleaner.

Faster but not furious

The motors, and circuit and transmission technology, are the same as the latest Dura-Ace, which leads Shimano to claim an increase in shift speeds: 58 per cent faster rear shifting and 45 per cent faster front shifts over the outgoing R9100 Di2.

Those are impressive percentage drops, though we’re only talking fractions of a second in current shift speeds. That said, my colleague, Matthew Loveridge, has been very impressed with shifting – and front shifting, in particular – on the new Dura-Ace groupset.

Shimano has also been working to control shifting vibration and noise with its new cassette-tooth ramping profiles.

Shimano claims the new cassette profiles give ‘shockless’ shifting even under the heaviest of pedal loads, so you’ll never have to back off accelerating or soft pedal to shift with this new design, which Shimano has coined Hyperglide+.

A dozen gears

Unlike rivals SRAM, with its AXS group, Shimano’s transition to 12-speed for its electronic drivetrains hasn’t meant a re-shaping of the gearing. To recap, the launch of 12-speed SRAM Red eTap AXS saw SRAM reduce chainring sizes, while also introducing a 10-tooth sprocket on the cassette.

Instead, Shimano is sticking steadfastly to the regular 52/36t and 50/34t chainset options. There are two cassette options of 11-30t and 11-34t (Dura-Ace does get a massive 54/40 chainset and an 11-28 cassette option as well, if you're looking for that truly pro-level gearing).

So what's Shimano's reasoning for shifting to 12-speed? The addition of a twelfth sprocket has allowed Shimano to broaden the ‘sweet spot’ between the sixth, seventh and eighth sprockets. As a result, this is the progression for the two Ultegra cassette options:

• 11-30: 11-12-13-14-15-16-17-19-21-24-27-30
• 11-34: 11-12-13-14-15-17-19-21-24-27-30-34

The sportier 11-30t cassette has single-tooth jumps for the first seven gears, which should create a super-smooth platform for your cadence, whereas the broader 11-34 gets five one-tooth jumps before moving to two-tooth jumps for the next three again, offering progression with narrower gaps than the existing 11-speed cassettes.

Power to the people

Shimano’s entry into the power meter world has been a little slower than we expected. Where SRAM has continued to bring power measurement down to more affordable price points with Rival AXS, Shimano has seemed to be content in just having its Dura-Ace power meter and relying on third-party brands to adapt its existing chainsets (including the two options linked below).

• Stages Dura-Ace G3 L-R Power Meter
• 4iiii Precision Dura-Ace 9000 power meter

That’s all set to change, though, with the new Ultegra-grade power meter that launches alongside the new groupset.

This dual-sided FC-R8100-P power meter is built into the new shape of the R8100 chainset and Shimano claims it will provide 300+ hours of riding from its waterproof, integrated Li-ion battery.

Dual-sided data measurement comes from Shimano’s strain gauges in both crank arms and data is transmitted in Bluetooth and ANT+. The power meter chainset is available in 50/34t and 52/36t chainring options.

Stopping powered up

Now let's talk about braking – and this is where the current Ultegra Di2 R8000 could perhaps use the biggest update.

Ultegra hydraulics are excellent but in our experience are prone to occasional rotor rub in the mucky winter months. And compared to the brilliant ergonomics of the latest GRX Di2 levers, R8000’s braking feel from the hoods is left a little wanting.

Shimano has, as expected, brought learnings from the GRX gravel groupset, as well as the MTB groupset side of the company, to the new levers and brakes.

First, the lever shape now has a raised head and an inward curve to the lever itself – something that will feel very familiar to GRX Di2 users. This has the effect of increasing the space between shifter and bar, improving comfort when riding in the drops.

The raised head of the hood also means a much better – and firmer – hold at the hoods and the ability to get three fingers on the brake lever, again when holding the hoods.

Combine this with the Servo Wave design from GRX, which reduces the amount of free travel in the lever before the brake engages, and it’s potentially the upgrade we've been looking for when it comes to braking from the hoods.

To finish off the STI improvements, there is also reach adjustment with allowance for 16.4mm at the lever tip.

On the shifting side of the STI levers, the offset between the Di2 buttons has been broadened to apparently make it easier to differentiate between the two, especially when wearing thick winter gloves.

Ultegra Di2 vs Dura-Ace Di2 weights

For a long time, we’ve been of the mind that the differences between Dura-Ace and Ultegra are minimal. With performance between the two groups, both mechanical and electronic, being so slight, why would you choose the more expensive option aside from some weight savings, aesthetics and sheer want?

With the new 12-speed Di2 systems, we think that’s set to become even cloudier, with the weight differences now even closer.

For example, the new smaller front mechs differ by just 20g (about the weight of a mouse). The rear mech is just 37g heavier (or about the same as a packet of cheese and onion crisps).

Even with the big mechanical items, the difference isn’t much – the cassette is about 73g heavier and the chainset just 21g more in a 52/36t chainring setup. Continuing the theme, the shifters are just 41g heavier per pair and the (disc) brakes 53g heftier (pair).

In fact, the total groupset weight is 278g heavier. For context, a full 500ml bottle weighs in at over 640g, so we’re not talking huge differences here across the board.

When you factor in that both new Di2 groups effectively share the same mechanics and electronics, any compelling reason for Dura-Ace seems to disappear further.

Is Dura-Ace set to become the pro-only group where small gram savings are more important than budgets?

Shimano Ultegra R8100 vs Ultegra R8000 vs Dura-Ace 9200 vs Dura-Ace 9100 weight comparison

Finally, wheels deserving of the Shimano name

For too long now, Shimano’s wheel offerings have been… how would you say? Safe. The designs have been conservative and weights middling. Yes, they’ve always been very well made but we doubt they’ve ever been atop anyone’s wish list when it comes to the very best road bike wheels.

The new range comprises Ultegra C36, C50 and C60 carbon options, and here Shimano has upped its game significantly, with an all-new rim profile and a new family of wheels to showcase the shape.

The rim shape is the same as the new Dura-Ace wheel line-up – though, unlike Dura-Ace, Ultegra gets no tubular tyre options and no rim brake options either (the current RS700 wheels will continue).

The rim shape combines a 28mm outer width and 21mm internal, with rim depths of 36mm, 50mm and 60mm. The construction has been focused on increasing drivetrain rigidity and Shimano claims a 9 per cent increase in stiffness over the current Dura-Ace C40-TL.

The C36 wheelset is aimed at riders who like to climb because it offers the best combination of low weight with the aerodynamic rim shape.

The 1,488g claimed weight is heavier than the new Dura-Ace equivalent (1,350g) but on par for a £1,260 wheelset. For comparison, Hunt’s similarly-deep 35 Carbon Aero wheels weigh in at 1,357g (£859), whereas Specialized Roval C38 wheels (£1,250) come in at 1,600g a pair.

The C50 is designed as the all-rounder's choice with its 50m-deep rim and 1,570g claimed weight for the pair. Again this is a competitive weight with similar shaped and priced wheels, like Vision’s SC55, coming in at £1,150 and 1,566g. Compared to the new Dura-Ace option, these are 109g heavier for the pair.

Finally, the C60 wheelset is aimed at speedsters and TT riders, with its deep 60mm profile, and weighs in at a claimed 1,649g a pair, which is only 40g heavier than its Dura-Ace equivalent.

Shimano Ultegra R8100 and Dura-Ace R9200 wheel weights

Shimano Ultegra R8100 wheel prices

• Ultegra R8170-C60-TL C60 carbon clincher F12 front: £579.99
• Ultegra R8170-C60-TL C60 carbon clincher R12 rear: £679.99
• Ultegra R8170-C50-TL C60 carbon clincher F12 front: £579.99
• Ultegra R8170-C50-TL C60 carbon clincher R12 rear: £679.99
• Ultegra R8170-C36-TL C60 carbon clincher F12 front: £579.99
• Ultegra R8170-C36-TL C60 carbon clincher R12 rear: £679.99

Where next?

Perhaps the biggest question facing Shimano buyers is the future of mechanical groupsets.

With Shimano's new Ultegra and Dura-Ace groupsets going electronic-only and 12-speed, there's a bigger divide than ever between the latest mechanical and electronic setups.

With almost no crossover parts between electric and mechanical groupsets (aside from disc rotors, also shared between mountain and road), does that mean Shimano is pulling back on mechanical development?

Will we see new mechanical groups going 12-speed or will they stay at 11-speed, limiting upgrade options for the future? On the plus side, the simultaneous release of Dura-Ace and Ultegra means plenty of crossover and upgrade potential here from the off.

Unfortunately, we can’t bring you any insights into the new Ultegra Di2 as our test chassis is still sitting with Shimano awaiting parts before we can run it through its paces. As soon as our bike arrives, we’ll get it thoroughly tested and report back.

Shimano Ultegra Di2 R8100 pricing & deals

Bottom bracket cups

• Bottom bracket cups: £34.99

Chainsets

• FC-8100-P (with power meter, 52/36 and 50/34 chainring options): £999.99

Cassettes

Chain

Rear derailleur

Front derailleur

• Seat tube adaptors: £16.99

Gear shifters (STI)

Shift switches

Brakes

• R8100 direct-mount rim brake front: £79.99
• R8100 direct-mount rim brake rear: £79.99
• R8110 direct-mount front: £89.99
• R8110-RS seatstay direct-mount rear: £89.99
• R8170 caliper flat-mount front (with adaptors): £74.99
• R8170 caliper flat-mount rear (no adaptors): £74.99
• RT-MT800 Ice Tech FREEZA rotor (with lockring): £49.99
• Flat-mount road caliper adaptor (rear) 160mm: £13.99

E-tube SEIS Di2 cables

• 150mm–860mm wires: £24.99–£28.99

E-tube SEIS Di2 bottom bracket junction

• Two-port: £20.99
• Four-port: £27.99
• E-Tube SEIS Di2 battery: £174.99
• EQ-EC300 charger: £44.99

Wheels

• Ultegra R8170-C60-TL C60 carbon clincher F12 front: £579.99
• Ultegra R8170-C60-TL C60 carbon clincher R12 rear: £679.99
• Ultegra R8170-C50-TL C60 carbon clincher F12 front: £579.99
• Ultegra R8170-C50-TL C60 carbon clincher R12 rear: £679.99
• Ultegra R8170-C36-TL C60 carbon clincher F12 front: £579.99
• Ultegra R8170-C36-TL C60 carbon clincher R12 rear: £679.99