Product Review: Shimano Dura-Ace Di2 Group

Reprint from Triathlon Club of San Diego TriNews April 2010 newsletter

Trickle down technology… Formula One paddle shifting meets todays cyclist. Shimano’s electronic shifting is one of the most exciting advancements in cycling technology in quite a while. Mavic gave it a try in the mid 90’s but was plagued with many faults. Even Campagnolo has been testing with an electric group for a couple of years. Shimano did not want to repeat Shimano did not want to repeat Mavic’s failures and proved it with the Di2. This group set was released to the public early last year but was used by many teams during the 2008 Tour de France. It is race proven and many thousand of hours were spent to verify/test if the system will work in extreme condition without failure.

Di2 shifters; road and two TT styles available, bar end shifter and dual control shift/brake.

Being under the Dura-Ace component group set, it is being marketed to the high-end cyclist. At the moment, its price is keeping it a high-end product. In my opinion is should be an every man’s (and woman’s) product. I first saw the Di2 demo at last years TriFest in Tucson. Shimano had a small booth with not much fan fare. I fell in lust at first touch! Yes, I said touch. Shifting gears is now as effortless as pressing a door bell.

The Di2 system features a rechargeable Lithium Ion battery (lasting 1,000 miles and more) powering an integrated CPU that monitors and adjusts the front and rear derailleurs to keep them perfectly trimmed automatically. The system is claimed to shift 30% faster (as fast as you can move your finger) than with mechanical derailleurs – even under load while cycling out of the saddle.

I am using the complete group set which included the crankset with bottom bracket, front and rear brakes, all wiring harnesses, front and rear derailleurs, Di2 STI levers, battery, battery hanger, battery charger, choice of cassette, chain and special tape to conceal wires. I’m also using the dual TT shift components for my TT set up. One can obtain as an upgrade kit, which is sans cranks, cassette, chain and brakes. Using Shimano’s crank set will guarantee 100% precise shifting every time. Shimano’s brakes offer the best stopping power out there. I have used lighter and more expensive brakes but they do not have the same confidence and stopping power. Powerful brakes allow one to travel faster with confidence.

I had Nytro Multisport do the basic installation of the components and they did a flawless job. Since I have a unique bike (Ritchey BreakAway), I wanted to do the final wiring myself. Bikes without internal wiring already built into the frame need to make sure there are no loose or extra wires flapping around. (update: last week I saw a gal taking in her tri bike back to the bike shop with rubbed out wiring… she was at IM COZ and apparently DNF due to bad installation.) This is essential for a clean and professional installation.

Hiding as much wire as possible.

Wire harness nicely concealed behind supplied down tube tape.

update: and TT set up image.

My old shift set up (Modolo Morphos) had just expired after a little more than two years of solid use and time to replace with another set I had ready to go or make the big investment. I’ve used Shimano Ultegra and Dura-Ace STI shifters in the past and they only lasted a few seasons and quite expensive to replace that often. Today’s Shimano products are much better. Better construction, quality to meet the demands and tourchers of today’s athletes and last much longer.

For me, the extra dollars spent on the Di2 version over that standard STI is actually not much when comparing the benefits. Here’s why:

One Touch Shifting: Simple as that, one no longer has to “force” the shift to happen. It is crisp and exact. Ever struggle to shift when your fingers are frozen. It’s just about impossible, now, it’s just firm press of a button and presto, gear changed. The two piece shift “levers” are placed just like the traditional paddles, very instinctive and intuitive.

Components Lifespan: Since there are less mechanical parts, all the components will last longer. The front derailleur will last longer because one is not forcing a shift up or down. Less wear on the chain guide, crisp and exact shifting every time. The rear cassette and chain will last longer because the chain is precisely in the center of each gear. Shifters no longer have any mechanical gears to break or wear out.

Full Gear Selection: Since Di2 is auto trimming, one will have access to all gears. No more chain rubbing that may have limited certain gear combinations.

Be Faster: Faster and exact shifts, not having to look down at the chain every shift or front derailleur, not having to be cautious while shifting between chainrings for fear of a chain drop. Those slight hesitations add up over the length of a ride or race. They are now a thing of the past. I anticipate to have faster bike splits once I get my fitness level back to previous levels.

Less Maintenance: No shift cables means there is nothing to stretch and constantly need adjusting. Just keep your battery charges. Each charge should last over 600 miles.

Blood Pressure Reduction: Yes, one’s health may even improve. Since one will no longer be fighting with their equipment; chain dropping, gears not shifting cleanly, chain rubbing, etc…. All gone. One will be smiling and enjoying cycling more.Are there any drawbacks? Yes, but not enough to keep me away.

Installation: I suggest having a qualified technician do the initial installation. It will save you time in the long run and be less frustrating. Managing the wiring harness may be something more personal. For me, I wanted to make sure I had just enough wire exposed for shifting and it was routed to my liking. Shimano has a great visual installation tutorial on their website to accompany the supplied installation manual.

Mechanic Friendly: Not every bike shop is Di2 savvy yet, and if traveling to a race Di2 support is most likely a not. The good news is that you really should not have any problems once set up properly, maybe a simple high/low stroke adjustment.

Price Point: Yep, the group or upgrade kit does cost a pretty penny. I hope the price will drop so everyone can enjoy the benefits it adds to the cycling experience.

With all the rain over the last several week ends, I have not been able to put the amount of test miles in as planned. However, miles on the CompuTrainer and limited outdoor mile continue to amaze me. My learning curve was very short, I still goof up (pressing the wrong levers once in a while) since I am not used to Shimano’s dual control system. California 70.3 will be my first race using the TT set up. I was anticipating a personal best bike split here but training has fallen off a cliff. I’ll just have to be satisfied with the most hassle free and worry free bike splits in my career.  (update: I did have my fastest bike split this year, faster by 3 minutes. It may have been the wind conditions but I believe it was due to the precise shifting of Di2.)

If an upgrade in drivetrain components is in the near future or looking to make your cycling experience more enjoyable look no further than Shimano’s Di2 components. It should be at the top of everyone’s list. Money spent here will be more noticable than a set of race wheels or disc or even a new frame. You will use it every ride and will notice the investment every mile. And retrofitting any older frame is pretty straight forward.

Some of the local bike shops have demo bikes with the Di2 system, go for a test ride and see for yourself or stop by the Shimano booth at your next race expo. Complete information on the Dura-Ace Di2 group can be found on Shimano’s website.

Dean Sprague, owner PedPowerPerform Lab, Retül and F.I.S.T Certified Bike fitter. The only Retül (3D Active Motion Capture) fitter in the San Diego area.


2 thoughts on “Product Review: Shimano Dura-Ace Di2 Group

  1. that type of event would be perfect. IM wisconsin for example requires lots of shifting… Shifting is crisper and exact. No need to slow pedaling to make sure shifting goes properly. and with the brake/shifter combo, shifting coming out of down hill sweeping corners is awesome. Power up and down at will, no delay due to having to balance elbows on pads before shifting. And if already suing drop bars with STI, shifting is much improved. You will be faster with Di2 (as long as yo keep your fitness level in tact)

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