Shimano recently announced an electronic shifting system designed initially for high-end road racing bicycles: DURA-ACE with Di2 technology. Shimano’s marketing officer Harald Troost is convinced that this novelty will change the road racing scene drastically…

CHAIN REACTION: Electric fever

We consider this introduction as the start of a completely new era, characterised by electronic controls in the road cycling world. In a few years time, the majority of riders in the professional peloton will shift electronically. And also in the consumer market, many riders will change to an electronically operated system. The use of electronics in the production of bicycles will open up a completely new world of opportunities of which we cannot see the broad perspective yet. In the near future bicycles could incorporate features and functions that have been out of our scope until now. In our view, electronic shifting is just the beginning and other electronic features could be integrated in the near future.
This new era also means that bicycle dealers will need to be trained to handle the new requirements of electronic systems. For this purpose, Shimano is setting up dealer training to teach how to mount and adjust these components.

As mentioned above, a good start has been made with the new DURA-ACE group with electronic Dual Control Levers (the shifters), front derailleur and rear derailleur and the battery. The other components of the group (like crankset and brakes) are equal to those of the new mechanical DURA-ACE 7900.
The advantages are clear immediately. Shifting becomes much easier and effortless; just tipping a shift button is sufficient to move the chain to the requested sprocket or chainring. The biggest improvement is shifting the front derailleur. No more power is needed to move the shifting lever. Just push the button and it works, even under high load. The shift action is also faster compared to a mechanical system since there is no delay due to mechanical friction.
This shifting system allows accurate and effortless shifting in the most difficult circumstances. For example, when the rider has cold hands or is completely exhausted. Furthermore, the shift buttons have been designed in such a way that they can also be controlled easily with gloves on.
No longer will contaminated or stretched cables cause malfunction. Input is output. No matter if the system is new or has been used for years.
When shifting the rear derailleur, the front derailleur automatically adjusts itself, which eliminates the need to trim once and for all. Further benefits can especially be found in time trial and triathlon. Additional shift buttons will be available that can be integrated into the time trial bars which offers the rider two locations to shift, eliminating the need to change hand position for shifting.

The system uses a 7.4V Li-Ion battery. You can ride it at least 1,000 kms before you need to recharge it. Recharging can be done within 1.5 hours by using the Shimano charger and we guarantee that you can recharge it at least 500 times. A simple calculation shows that you can ride at least 1.000 x 500 = 500.000 km before you need a new battery.
The system has a battery indicator and even when the light turns red, one can still ride around 250 km. If you keep on riding without recharging, eventually the front derailleur will start moving shortly before it stops completely. But shifting the rear derailleur (that needs less power) will still be possible for some time until the battery is completely empty.
In practice, this situation will not occur when the rider recharges every 1.000 km.
The shifting system is not wireless since that would need additional power (a heavier battery) and it would also be less reliable than the technology that Shimano has chosen. Shimano is in discussion now with several bicycle manufacturers who are developing frames with an internal cable routing to make a clean looking, high tech road racing bicycle that will appeal to many racers as well as consumers.

For road racers, weight is of course an important issue. We have managed to make the new DURA-ACE group with Di2 components around 75 grams lighter than the previous DURA-ACE 7800 series. Compared to the new mechanical DURA-ACE 7900 series, the group carries only about 55 grams more weight.
Total weight for the DURA-ACE group with Di2 technology is around 2,100 grams. Weights are still tentative since mass production has not yet started.
We have been testing the new electronic shifting system for over two years by professional road racing teams such as Team Rabobank, Team Gerolsteiner and Team Skil-Shimano. There were many difficulties we had to overcome, of which two of the most important were weight and challenges with shocks. Over time, we managed to decrease the weight a lot by making the battery smaller and more effective. And at this moment, the technology copes brilliantly riding on cobble stone classics and in heavy weather circumstances. In that sense, the professional road-racing scene is the best testing ground one could imagine. The only issue we have at this moment is that our test riders don’t return the prototypes before they get a new Di2 version since they don’t want to go back to riding mechanical components!
We have also learned a lot from the introduction of electronic shifting and suspension systems in the comfort bike segment more than five years ago. Some experiences of these days (like making electronic components weather proof) we could use very well in the development of the electronic systems for road bikes. In other areas (eg. lightweight design, quick shift actions) we had to start all over again.
The bicycle is easier to control so the focus on the ride itself increases. But of course the most important engine was and always will be the rider itself…
DURA-ACE components with Di2 technology will be available in the market from Spring 2009.

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