Dura Ace Di2 9070 Groupset review

I’ve been using the Shimano Dura Ace di2 for a couple of months now, so I thought, after extensive testing, I would give a review.

Overall, I’m very impressed. It is very good and makes a difference over mechanical shifting. It is very expensive, and initially I was regretting spending the money on Dura Ace, when I could have saved a £1,000 and got Ultegra, but now I’m glad I ‘bit the bullet’.

For many years in cycling, ‘electronic gears’ got a bad press. When electronic gears were first introduced, they were often reported as ‘freezing in big races’ and this put me off electronic for a long time. But, Di2 seems to be very durable.

Dura Ace Di2 – 56*21



I’ve been using for a couple of months, without any issues, but to get a better perspective I asked my mechanic friends at Beeline. Mark said they have seen a lot of people use Shimano Di2, and it has been excellent for durability and easy of maintenance. He said it was a lot more reliable than other electronic gears. Mark said many people just ride their bike all year and get it serviced once a year. He said Di2 was good for those riders who didn’t want to do anything but just ride and recharge their batteries. He seemed quite enthusiastic about Di2 and would recommend it as the best groupset.

Another big thing of electronic gears is that you don’t have to worry about frayed cables or adjusting gears because of stretched cables. This is another reason why it makes it easy to maintain.

The batteries last for a long time – a couple of months. I recharge every month, even if the battery light doesn’t come on, because it’s hard to believe it can last for so long (unlike the iPhone, which seems to go dead very quick)

Ease of use

The main attraction of electronic shifting is that it is claimed to be easier to shift, quicker and more reliable.

I have had some problems setting up Shimano Di2. When I put a 56 chain ring on, I tried moving front derailleur and I got it at an odd angle and this made a loud clicking noise for a while. There is a very small screw to adjust angle, but I didn’t find it first time. I took to bike shop and they got it fixed.

Apart from that it has worked very well. As mentioned in recent review of workstand I often need to adjust the gears. The hub of the training wheel is in different place to hub of disc-wheel. When I swap wheels, I have to adjust the gears – which is a bit of a pain. (but an issue for any groupset) Fortunately the Di2 groupset is quite a nice piece of equipment to adjust.


Put it in adjust mode and make fine adjustments until the gears work smoothly. It is quite satisfying job, and easy than mechanical adjustment. I’ve always struggled to satisfactorily adjust gears on mechanical gears, but it’s one job you really want to be able to do. The Workstand does make it a lot easier.

Gear Shifting

Once set up properly, it is a dream to shift gears. Because I do hilly time trials, I like to have the biggest range of gears possiblye 39-56 chainrings on the front. Cassette 25-11. Shifting from a 39 chain ring to 56 is quite a jump. The only issue I’ve had is when pedalling slowly on rollers. It performs best under pressure in a race.  I’ve never missed a gear change in a race. With mechanical Dura Ace this happened quite frequently. I remember in Nat HC of 2013, shifting into the big ring, but it wouldn’t go – this was a big problem. Di2 is more reliable in this regard.


The beauty of gear shifting with Di2 does encourage you to to change gears more frequently. It’s so quick you don’t really lose any momentum. Sometimes with mechanical Dura Ace I would think twice before shifting.


A good feature of Di2 is that you can have buttons wherever you want them. Rather than in just one place – you can have them on both the ends of the tribars and the sides. This means you can shift without moving hand position – another marginal gain.

One small thing is that it took me quite a while to get used to the buttons, I pressed up when I meant to press down, but this can be overcome through getting used to it. Also, I’ve been riding all winter with big thick ski gloves, you have to work hard to get right button. But, I wouldn’t really change this, I hope not to have to use ski gloves to do time trials.

If you wanted you can add more custom buttons e.g. on top of handlebars. You can also customise the gear changes – such as customising the speed of change – though I can’t see myself doing that.

Mechanical failure?

If you did get a mechanical, like battery wearing down, you can manually push the rear derailleur to change gear – so you can always get home.

Accept 28 T


A good benefit of the 9070 series is that it accepts a 28 cassette. I often want to use a 28 cassette on really hilly terrain. Pros also want to use 28 cassettes. I always thought it didn’t look good for Shimano when pros had to switch to Ultegra to get up the really steep hills.

Do we need 11 speed?

I was annoyed when 11 speed came out. I was quite happy with 10 speed and was more annoyed at the likely cost and inconvenience of upgrading. (I even wrote a post – please no 12 speed) But, when you actually get 11 speed, it’s quite nice – especially when so easy to change.

Of course, we don’t need 11 speed, I would have preferred if everyone had stuck at 10 speed and we could all have saved a bit of mony, but now 11 speed is here, it is just a little better.

Automatic adjustment of front derailleur

One stand out feature is that when you change the rear cog, the system automatically adjusts the front dérailleur so that you maintain a good chain line and prevent rubbing on the derailleur. This means if you are in 56*12 and change rear cassette you can go up to say 56*23 and, as you do, the front derailleur automatically changes to prevent rubbing. It’s helpful to be able to stay in big ring for longer.


Weight of Shimano Dura Ace Di2 9070 is 2047g.

By comparison

  • Mechanical Dura Ace is 2074 grams
  • Ultegra 6870 Di2 – around 2,680g (I think this is wrong, I believe new Ultegra is just 300 grams heavier than Dura Ace, but I haven’t been able to find confirmation anywhere.)
  • SRAM Red 2013 mechanincal groupset. 1,670g
  • Campagnolo Record 11 Speed – 2039g

(note, I have not tested the above weights myself)

For weight weenies amongst us

Weight    2047
Front Derailleur    114
Rear Derailleur    217
Chainset    637
Shift Levers    237
Chain    249
Cassette    192
Brake Calipers    286
Bottom Bracket    65
Battery    50

I got these weights from Bike Radar article on Shimano Di2

Aesthetics and Aerodynamics


One of the  reasons for buying Dura Ace Di2 rather than Ultegra, is that the front derailleur hub is smaller and more elegant.


Ultegra is a little less aero

In general, with Di2, there are less wires going around and it is fairly compact. I put the batter case near the stem. Most wires can be hidden with a bit of internal routing.



Brakes are very good. Can’t think of anything else to say here.


The crankset is still made out of aluminium because SHimano claim it is stronger than Carbon.

Annoyingly I’ve ditched by four arm crankset to make use of my Quark Power meter, so I have a Shimano 9070 Di2 Crankset for sale on ebay very soon.


It is very good. It is hard to find any real meaningful faults. The only drawback of Dura Ace Di2 9070 is the price – it really is expensive. It’s annoying that something so expensive is so good because there is a big motivation to try and buy it. The good news is that Ultegra Di2 is just as good, except £1,000 – £2,000 cheaper!


External links

Dura Ace Di2 9070 at Wiggle

Ultegra 6870 at Chain reaction cycles

Dura Ace Di2 at Amazon.com

Review of Di2 9070 at Bike Radar


6 thoughts on “Dura Ace Di2 9070 Groupset review”

  1. Do NOT under any circumstances buy the Shimano Electronic shifting components. It will work very well – for a year. Then it will start losing charge so that every third time you get on your bike the shifter will be out of power and you will be stranded. You will take it to the bike store – multiple times – and they will upgrade the firmware, replace the battery and reconnect all the wiring. And it still will not hold charge for more than 3 rides. This problem is widespread among riders if you start researching. Do NOT buy this product!!!


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