Shimano Dura-Ace Di2 9070 11-speed gear system

Shimano Dura-Ace Di2 9070 offers swift, faultless shifting and a few extra features that make it an even better proposition than the initial version.

We ran a review earlier in the year of Shimano's top-level 9000 Series Dura-Ace mechanical components and since then we've been using the same 11-speed groupset but with 9070 Di2 electronic shifting swapped in to replace the mechanical options. In other words, we've been using the same chainset, chain, cassette, wheels, brakes, bottom bracket and pedals, but with Di2 shifters and derailleurs and, obviously, the addition of the required battery, wiring and so on.

We'll first go through the Di2 components individually.

Dual Control Lever ST-9070

£569.99
Weight 237g

Shimano say: State of the art Di2 electronic technology for instant, accurate shifts first time, every time, at the push of a button. Now 11-speed compatible, with enhanced feedback and improved ergonomics for easier access to the shift buttons from the top of the hoods. Cleaner wiring thanks to single-wire E-tube connection that also makes it easy to add satellite shifters for bar tops or in the drops.

• 11-speed compatible

• Improved ergonomics

• Enhanced feedback

We say: The shifters are simple to use. Most of Shimano's mechanical systems use the brake lever as a shift lever, the lever that moves the mech in the opposite direction tucked in just behind it. Here the brake lever is used only for braking and you get two buttons just behind it, one for upshifts and one for downshifts.

It's not quite as easy to get the hang of the Shimano system as it is to get used to Campagnolo EPS where your thumb performs one operation and your index finger another, but you soon get the idea.

Even though the buttons are right next to one another, after a couple of rides you won't find yourself accidentally shifting in the wrong direction. The only time this could possibly happen is when you're wearing big gloves in the winter and your feel is compromised. It's easier to distinguish between the buttons than it was with first generation Di2, though.

Shifting is just a matter of pressing the relevant button so finger movement is limited to just a few millimeters. If you want to move two or more sprockets at a time, rather than swinging the lever further like you do with a mechanical system, you just keep the button pressed down (Campagnolo's EPS electronic shifting has a similar feature). This is an improvement over the previous generation Di2 where you had to press multiple times for multiple shifts.

You can personalise this multi-shift function, choosing the speed at which the system continues to shift from five different settings. You have to program this using PC software (it's not Mac-compatible, which is a pain for Mac users). You can also set the number of gears it will shift when you keep the button pressed. You can limit movement to two or three sprockets per press, or set it to 'unlimited' so that the chain will move right across the cassette.

While we're talking about customising the system, you can also alter the function of each shifter, so if you want to control rear mech shifting with your left hand for any reason, you can set it up that way.

Now, you might say that changing gear is easy enough with mechanical shifters and you'd be right, of course, but it's even simpler here. Whether your hands are on the hoods or on the drops, the buttons are easily accessible and you just tap the right one for an instant shift. No, it's not going to be the difference between winning and losing a race, it's just... better. Well, actually, I guess some people might still prefer the feel of mechanical shifting, but most riders we know who've tried Di2 would rather stick with it, all other things being equal.

Plus, with Dura-Ace Di2 you can add satellite shifters to give you multiple shift points. So, you can add another switch to the top of the bars for easier changes when your hands are resting up there when you're climbing (£89.99), or attach shifters to the drops for easier shifting when sprinting (£109.99). We used the sprinter shifters on a Bianchi Oltre XR2 recently. You perform upshifts with one thumb and downshifts with the other thumb. It takes just a few minutes to get used to it and after that it becomes second nature.

These have to be plugged into a handlebar junction box. These come in three or five port versions, two of those ports being taken up by wiring from the Dual Control Levers.

The lever bodies are really slim compared to Shimano's lower level mechanical shifters, as are those of Dura-Ace 9000 mechanical shifters, so it's easy to grip them firmly in your hands. The feeling is that you have just a bit more control over the front of your bike when your hands are on the hoods and you're riding out of the saddle. People with smaller hands will appreciate this even more. The new dual compound hoods offer really good grip in both wet and dry conditions too.

As a race-orientated groupset, Di2 only works with double chainsets, by the way. There is no triple version.

Rear derailleur RD-9070

£549.99
Weight 217g

Shimano say: Precise, lightning-fast shifts across an 11-speed cassette, whatever the conditions, with just a button click. The 9070 rear derailleur is now more compact and lighter, with E-tube connection to simplify installation. And automatic crash protection moves the cage out of harm's way.

• 11-speed design

• Automatic crash protection

• Maximum sprocket 28T

• Compact, lightweight body

We say: It works. The guys at the UK Shimano imporer Madison set up the system for us about three months ago and it has performed flawlessly since then. You can micro-adjust the shifting quite easily in order to get the chain position spot on but we haven't needed to do that.

Unlike a mechanical system where gear changes feel slightly different depending on the gear you're shifting to, with an electronic system the feel at the lever is consistent every time. Shifts are fast and accurate while the mech is smaller and lighter than before. It's now capable of working with a 28-tooth sprocket whereas the previous maximum was 27.

All in all, the rear mech does its job well and requires next to no attention. All good.

Front derailleur FD-9070

£369.99
114g

Shimano say: Precision actuators move the cage swiftly and smoothly for fast, silent, accurate front shifts every time. And with single-wire E-tube connection to the rest of the system, the front derailleur is able to automatically trim itself as you shift the rear derailleur, eliminating chain rub.

• Fast, precise, smooth shifting

• Automatic trimming

We say: Again, it works beautifully. You might not be enamoured by the looks of that bulbous motor housing up top, but it's difficult to fault the performance. It hits the spot every time.

A strong feature is shifting to the larger chainring when you're riding out of the saddle. With a mechanical system you sometimes have to take that tentatively. This Di2 system couldn't care less; it handles it without a worry.

As with the previous generation Di2, the front mech will auto-trim as you move the chain across the cassette. In other words, it'll reposition itself slightly to avoid the chain rubbing on the side plates as the chain angle alters. Of course, with a mechanical system you can do this yourself easily, but it's just something less to bother you. These things add up!

Battery

£59.99
Weight 68g

Shimano say: The lithium-ion battery is now available in two versions, suitable for both external and concealed internal mounting. A single-wire E-tube connection and new junction units for a cleaner look and easier installation.

• Long battery life (up to 2000km when fully charged)

• Available for external or concealed mounting

• Electric wires (EW-SD50) available in a range of lengths from 150mm to 1400mm

• 3 and 5 port junctions for cockpit area available. 5-port includes wireless unit

• Special PC interface (SM-PCE1) for system diagnostics and customising the system

We say: We'll all doubtless look back in five years and wonder what the hell was going on with such a large battery, but it's small enough not to be in the way of anything. We've not used the internal battery (£129.99) yet, by the way, just the external version.

People always ask what happens if the battery runs out when you're in the middle of nowhere. Well, you'd have to be pretty inattentive to allow that to happen. The vast majority of people will only have to remember to top it up every few weeks (depending on how much you ride and how often you change gear, obviously). Even if it does run out of juice, you can position the mech so that the chain runs in the sprocket you want and ride home in a single gear. It's really not an issue.

You'll also need a battery charger (£64.99), the relevant wiring (£various), a handlebar junction box (£89.99-£109.99) and a bottom bracket junction box (£24.99). The handlebar junction box links the shifter cables to the rest of the system and it's now available with both three and five ports.

The wiring is different from before. It has gone from having four inner cores to two, so it's significantly narrower and the connectors are smaller so they require smaller holes in the frame for internal cabling.

Conclusion

Overall, 9070 Dura-Ace Di2 is an excellent system with significant changes from the first generation version. The slimmed down levers and the multi-shift function are both considerable improvements. Plus, of course, this is an 11-speed system rather than 10-speed as before.

The Di2 derailleurs are still a little heavier than the mechanical equivalents but the levers are lighter so there's very little difference in the overall system weights. Shimano reckon that a Di2 set-up with an internal battery is actually a touch lighter than a mechanical version, removing one argument against going electronic.

Should you switch to Di2? Well, it's certainly an expensive outlay compared to a mechanical system but all the little benefits - accuracy, reliability, ease of use, auto-trim, multi-shift performance, possibility for satellite shifters – add up.

If Di2 was the same price as Dura-Ace 9000 mechanical, I'd certainly go for Di2. The price issue complicates things, and only you can decide whether you're willing to pay the extra compared to mechanical set up. Personally, I'd say that Di2 9070 makes a compelling argument for switching to electronic. While it won't transform your riding experience, it's likely to enhance it.

Verdict

An expensive outlay, certainly, but accuracy, reliability, ease of use and many other benefits make this an excellent system.