Shimano XTR Di2 Revolutionizes MTB Riding
Electronic shifting became a standard thanks to Shimano’s Di2 components, on the road. Now the technology is going off-road and more – delivering functions that will probably migrate back to the road in the future.
Shimano XTR Di2 is based on the new mechanical XTR M9000, introduced earlier in the season. The drivetrain now has a cassette with 11 chainrings and is available in configurations 1x, 2x, and 3x. All of this stays unchanged for the electronic version Di2 M9050. From here on is where it gets interesting, but also where problems for R&D team really started.
“The real challenge was to build a stable drivetrain,” said Shimano’s product manager Bas van Dooren.
“We have road Di2 derailleurs for a while, but this is something completely different. We had to combine the Shadow Plus system and a very robust electric motor. The power consumption is much bigger due to Shadow, since the spring in the derailleur is much stronger and we had to use a more powerful motor. Another big challenge was to create functions that makes life of a rider easier, like Syncro Shift.”
“We started to think about it after we launched first generation of Dura-Ace Di2, but the real development started three years ago,” explains Hidekei Ikemoto, Product Manager at Shimano. “XTR Di2 not just for XC racing but also for other styles of mountain biking like trail riding and enduro.
Test riders in these categories also like the system very much. Enduro riders prefer the 1x system, trail, and all-mountain riders chose the 2x system. We also tried the components on the downhill bikes and they did their job. At first we used modified Dura-Ace levers, but the system didn’t perform on the mountain bike. We had to do a lot of changes and new components.
For example the construction of the shift lever is totally different, so we kept that “click” feeling mountain bikers are used to. It could also go in the opposite direction, there is a lot of interest for Syncro Shift among the road riders. As Di2 road components are already used for cyclocross, where you often have rain and mud, performance under these conditions was not an issue. Bigger challenges were the riding style and the obstacles on the trail. For this reason the components are much more robust and have a different assembly.
Our advice to the frame manufacturers is to use clean lines and internal routing. The Di2 Road and MTB systems are compatible, but not all components. The sprint switch for example is not compatible with MTB groupset, and you also need a specific XTR front derailleur. With suspension and a lot of shifting a fully charged battery lasted for 285 kilometres on the 2×11 drivetrain. Of course this varies from rider to rider, depending of terrain and air temperature.”