Nathan’s Long Term Shimano Dura Ace Di2 Review

Shimano Dura Ace Di2 on a Pinarello Prince, photo by Ward Bates

One of the most interesting developments in recent cycling technology was the wide release of Shimano’s electronic shifting component group. While this technology has been around for about 20 years, it’s only with Shimano’s Di2 that things really got interesting. This year, pro teams are using Shimano Di2.

Shimano Dura Ace 7900

With quite a few bike manufacturers now making frames that are compatible with the internal wiring kit of Di2, it’s become quite ubiquitous to have their top model sport Di2. Naturally, the component groups is pricey. I’ve seen prices between $4,000-5,000 USD, though it’s not uncommon to find it for $3,500-$4,500 USD. Giant, Willier, Pinarello, Scott, Colnago, and most others produce frames that allow internal wiring.

Since it’s the top of the line component from Shimano, you’ll naturally find quite a bunch of fanboys gushing profusely about it. It’s hard to decide which review is objective and which isn’t. For most of 2009, I was a bit skeptic about this component group. Even if it could be found for the price of Campagnolo Super Record 11, was it actually worth it?

This is similar when some customers were trying to find out the differences between the Prince and the Dogma. There aren’t many un-biased reviews out there.

This is where Nathan’s review comes in. He’s a bike enthusiast and a Campy fan. This is what he did to get the gruppo:

Sell everything you own to make it happen. (I sold framesets, a Super Record 11sp grouppo, a Chorus 11 mini grouppo, multiple Campagnolo wheels and cassettes to make it happen on 2 bikes for me. That’s saying something for a lifelong Campaphile.)

Nathan paid for it himself and he’s been a Campy fan. The other thing is that he actually tried to make it fail. He didn’t succeed.

Although the battery is mostly placed underneath the bottle cage, which I find awkward, some bike manufacturers are placing them underneath the chainstay on the non-drive side of the frame. While this might look good, it can get problematic. Still, bike companies reason that most Di2 users won’t be doing cyclocross races with this, and they’d be right.

Shimano Dura Ace Di2 covered in mud, photo by Nathan

Luckily, Nathan actually did put his two Di2 component groups through grueling tests. He used them in cyclocross races and they performed exceptionally well.

Nathan's handiwork as he splits the battery, photo by Nathan

In addition, he’s currently completing a TIME VXR build where he has taken the battery inside his seatpost. There is no outside wiring. It’s all done internally through the frame and this is quite awesome. The process involves shedding a few grams by splitting open the battery and pulling the apart. They are housed in the seatpost and can be easily recharged.

New wiring of the Di2 battery, photo by Nathan

Both of these are solved by putting the batteries inside the frame. That’s the future of Di2 and what I did to my ride- internalized the batteries. Don’t be surprised if PRO starts making a seatpost with internal Di2 batteries. Look for more system integration here.

Shimano Di2 battery popped under the seat

Its like the hand of God reaches out to grab your chain and place it on the chainrings/cogs. I could rave here but will spare you and just say without a doubt its the best shifting groupset ever made. I’ve had every top group out there and Di2 crushes them all in pure performance. No, I don’t miss the natural clunks or multiple shifts with Campagnolo. Nor do I miss the tin feeling taps of SRAM. Di2 is quiet and works every time. I missed maybe 2 or 3 shifts over the course of this review- both were in muddy races where I was cross eyed and couldn’t click a mouse to save my life.

One of the points that needs improvement is the crank. It’s quite heavy and not as performing as the aftermarket weenie stuff from THM Carbones. However, I wonder if Di2 will work properly with different cranks and chainrings. From everything that I have read, it should have no problems. What I mean, is that without any loss is efficiency. I put the question to Nathan and here was his reply:

The clav’s [THM-Carbones Clavicula carbon fiber crankset] will be great with Di2 as they gratly reduce the weight of the group but dont compromise stiffness. The front shifting really depends on what big chainring you use and the size. For example a 7800 46T shifts even better than the 53 7900 ring due to its smaller difference between the chainrings. There are so many aftermarket 110 or 130 bcd big rings to try.

On my weight-weenie bike I found a Stronglight 50t with a 36 inner to be not as good as 7900 but no real loss of performance. It was a good compromise between, weight, performance and aesthetics. I don’t have a lot of miles on the set up at all so it may be too early to tell. I definitely wouldn’t go with a Tune front chainring. Jason at FWB said even the Fiberlyte rings work well with Di2. To the contrary- there are reports the carbon-ti rings shift relatively poorly with Di2.

If you find the price a bit too high, you’ll be happy to find out that Shimano is working on an Ultegra Di2 component group. It might come out this year. Needless to say that I can’t wait to see SRAM electronic shifting group and Campy, when they finally decide to release them.

Alternatively, you can purchase the Shimano Dura Ace Di2 Electronic Shifting group, which will upgrade your Dura Ace 7900 to 7970. These include shifters, derailleurs, the battery and all of the necessary wiring. These upgrade kits can be found for between $2,000-3,000USD.

If you are considering Di2, I encourage you to read through Nathan’s review. You can find it over at Weight Weenies.

Visit Asterisk*Cycles or email us at asteriskcycles at gmail dot com to find out more.

Author: range

I'm mathematician/IT strategist/blogger from Canada living in Taipei.

One thought on “Nathan’s Long Term Shimano Dura Ace Di2 Review”

  1. Hi,

    Thanks for the very interesting post. I’ve been searching the net to try to find the dimensions of the Di2 battery pack, but not even the instruction manual of Di2 mentions this. Would be great to have the details if someone happens to know – both caged and uncaged (cells) is of interest.


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