Being a tech geek in a world of IT, I am amazed with all the current technologies that are available to us. Smartphones, GPS cycling computers, Google Glass ... just to name a few. When Shimano introduced the new Dura-Ace 7970 groupset back in 2008 ... aka Di2, I knew I need to have it. However, due to the initial sticker shock, I waited until December 2011 to get it. Now that I had a good 1.5 years with the group (as of this review), I can safely share my thoughts on it.
Installation
I'll admit it ... I had the bike shop do the installation for me. With such an expensive group, I didn't want to mess it up and I am glad I paid the pros to do it for me. First when I had the groupset on my 2008 Orbea Orca, it had the external wiring set. Luckily the downtube was black carbon on the underbelly so the wiring housings camouflaged well with black electrical tape. However, it looked a bit messy near the drive-side bottom bracket, but you couldn't see it because it was hidden behind the crankset. About 10 months later when I upgraded my bike to a 2012 Cannondale SuperSix EVO, I unhesitatingly asked for the internal wiring upgrade ... and I am so glad I did. Internal wiring is SO MUCH cleaner and well worth the extra money. There are no wires or brake cables on outside of the top tube, downtube, and chainstays. If you plan on getting an electronic groupset like the Di2, do yourself a favor and make sure your frame supports internal wiring for electronic groupsets. It is worth the extra price.
Maintenance
This is where the group shines! Gone are the days of cable stretch or even a cable replacement because ... well ... there are no cables! If you need to swap wheels or cassettes, simply put the bike in the middle 5th gear and press and hold the button on the junction box near the shifters until the light turns red. Then each shift on the right shifter will move in 12 steps in each direction. Keep shifting up (going to a harder gear) until you hear a slight noise coming from the cassette. Then simply downshift four times and you are set. Press and hold the button again until the light goes off. Done! The Di2 shifts perfectly on day one to day 500+!
Battery life is amazing. Ever since I purchased this group in 2011, I charged it only three times. At this rate, the battery can literally outlive me! From a fully dead battery, Shimano claims that the battery can charge to full in 1.5 hours. While I never really timed the charges, I believe it. Most of the time, the battery will be charged with some charge left in it. Just don't forget the battery if you plan on loading your bike to your car on a long road trip.
Usage
Using the group is a dream. Like a button on a mouse, a simple click will shift the derailleurs up and down. No need to worry about rusty or snapped shifter cables. I really love the autotrim feature. Shift the rear up and down the cassette and you can hear the front derailleur making minor adjustment shifts depending on where the gearing is at. The autotrim was designed to eliminate front derailleur rub. This feature is something a mechanical feature can never do.
Front derailleur shifting is amazing! I thought the mechanical Dura-Ace 7900 was fast and awesome, but Di2 front shifting is a technical marvel! I can hammer out of the saddle and shift the front without any worry. It is that good! Even though Shimano claims that dropping the chain is almost impossible during a downshift on the front derailleur when cross-chaining (not recommended by any means), I did put a K-Edge chain catcher for a piece of mind and I suggest everyone do the same ... regardless if you have mechanical or electronic shifting.
Worry about getting the system wet? Don't fret! The way the wiring junctions are connected, I can see how the system is water tight. I rode my Di2 bike in the rain several times (not by choice). No ill effects on shifting or shifting performance whatsoever.
Unlike a mechanical system, though, the first generation Di2 can't perform multishifts. You can't "dump the cassette" by holding down the shifter button like the Campy mechanical group. Campy EPS as well as the new Dura-Ace 9070 Di2 do support multishifts in a way of holding down the shifter button. I thought I would miss this feature, but knowing how quickly Di2 shifts in general, I do not miss that feature.
Shimano also "recommends" using their own brakes, crankset, and chain. I run a set of PraxisWorks compact chainrings (50/34) on a BB30 Cannondale SiSL crankset with a KMC SL 10-speed chain (with a master link). It works wonderfully with the Di2 shifting group! I have people who have aftermarket brakes on their Di2 bike. As long as they are Shimano-compatible, the aftermarket brakes should work no differently than if installed on a mechanical groupset. Shimano's "recommendation" to use all Dura-Ace 7900 "drive and brake" components is all a part of their marketing ploy, at least to me.
Verdict
To me, Di2 just works and works VERY well ... period! I am intrigued with the new Dura-Ace 9070 Di2 with the multishift capability as well as 11 speeds and lighter weight, but I am happy and content with my Di2 7970 groupset. It hasn't given me any problems and the only issue is that the electronic spare parts are expensive if needed to be replaced due to damage or malfunction. Prices should go down as time goes by, but may never come down to prices that of their mechanical counterparts.
If you had any reservations about electronic shifting, don't. It is real and here to stay. It can only get better from here on out.
- James Lee
