03 August 2008

Dura Ace 7970 Di2: Electronic shifting is (coming) back

It's been fifteen years since Mavic introduced the world's first electronic shift system. An ambitious product, Zap (and its predecessor, Mektronic) never overcame production issues or became much more than a novelty. Over the past five years, though, we've been seeing more and more electronic shift systems being raced by Campagnolo and Shimano riders. It looks as though Shimano will be the first out of the gate when their new 7970 Di2 groupette hits the market in January.

The partial group (pictured right) is designed to work with Shimano's forthcoming Dura Ace 7900 group. Shifters, dérailleurs and a battery pack add only 68g to a conventional DA build. The front dérailleur houses a computer which coordinates the system, not just moving the dérailleurs on command but also trimming the front dérailleur based on the rear's position. The shift brake/shift levers (at 255g) are 40% lighter than their cable cousins and the shift action is essentially switch driven- they'll move in a similar manner to other STI levers, but that's more of a haptics thing. There will also be remote shift levers, which the TT and triathlon riders will appreciate, given that race placing there is often determined by seconds (which could be saved by remaining in an aero tuck or on the bullhorns).

The whole thing integrates with a new Flight Deck computer (which will have wireless data transfer capability) and is run by a Li-Ion battery. The battery is allegedly good for 1,000km between charges. No word on what gear the drivetrain will default to on loss of power.

Shimano's Devin Walton is quoted by Bicycle Retailer and Industry News providing some surprisingly candid insight: “Going electric helps to ensure precision that can make a rider faster and reduce mental fatigue. If you think about Formula One racing, the race cars use automatic and clutchless transmissions because the computer can create a faster, more synchronized and consistent shift than a skilled driver can manually,” which is fair enough. “That being said, those same technologies can improve performance for anyone and there is a certain novelty factor for those enthusiasts that like to indulge in the latest high tech equipment or use the same equipment that professionals use." People will buy it, so Shimano will build it.

I have to wonder if using electricity to perform a function traditionally performed by human muscles is crossing some sort of line. Sure, carrying a charged battery around probably consumes more calories than that battery can save, but it seems a little cyborg-y to me. Demos are expected to be available at Interbike at the end of next month. Hopefully pricing will be as well.

marc

www.bicycleretailer.com
www.velonews.com
www.bikebiz.com

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