Shimano's Dura-Ace Di2 electronic shifting to give road racers a time advantage
By Paul Best
April 8, 2009
April 8, 2009 Japanese bike component manufacturer Shimano seems to have the pro-cycling world in a bit of a spin with its newly launched electronic Dura-Ace road racing components. It’s still early days but already the Dura-Ace Di2 – which stands for digital integrated intelligence – is receiving favorable reviews, with talk of significantly slicker, cleaner gear changes and one expert opinion describing the electronic component series as “revolutionary”.
It has also picked up an IF product design award for innovation, functionality and design in the leisure/lifestyle category – which hasn’t done its early good press any harm.
The Dura-Ace Di2 7970 series features four main components – dual control levers, rear derailleur, front derailleur and battery pack – with optional dual control levers for time trials and triathlons and a satellite switch. The control levers feature an electronic shift button that riders simply push, just like a mouse click on your computer, to change gears. What’s key is it moves the chain to the sprocket, or chain-ring, much quicker than mechanical systems.
According to TestRider.com, Dura-Ace Di2 manages the operation 30 percent faster than Dura-Ace’s mechanical counterpart, with most of the improvement in shifting the front derailleur.
Another advantage, the electronic system’s derailleurs, which move the chain between the different-sized sprocket wheels on the bike, automatically “trim”. This means, when a rider shifts the rear derailleur, the front derailleur automatically adjusts, so there’s no need to trim. The result: no overlap or chain-rub. Also with an electronic system, there are no contaminated or stretched cables.
TestRider.com also reports that the ingenuity of the Dura-Ace Di2 lies in its ability “to shift the front derailleur while out of the saddle … (so) the harder you peddle, the smoother the shift. For any experienced rider used to planning ahead for front derailleur shifts under pressure, it is absolutely mind-boggling.”
While the smoothness of the electronic gear system can be enjoyed by anyone who rides a bike, the average cyclist is unlikely to care how fast their bike shifts gears and may baulk at the heftier price tag of Shimano’s electronic version (between USD$4000-USD$5000 for the main set of components).
In the super competitive world of professional road racing, however, any time saving, no matter how slender, may give a rider the crucial edge that might make all the difference. The dual control levers for time trial and triathlon provide additional benefit by eliminating the need to change hand position with the rider capable of shifting gear at the base-bar or bar extensions. Again, this provides another opportunity for riders to save time and it helps them to concentrate on the ride.
In the past, though, reliability has been at issue with earlier electronic gear-shifting attempts. Putting aside the deep pocket needed for the Dura-Ace Di2, questions remain about the ease of set-up and its all-weather durability. Only time – and plenty of road-testing – will tell.
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