- by Christopher Jones
- Published: 25 June 2014
Shimano are currently sweping across Australia and presenting their greatest and latest to the bike shops. But forget the recently updated disc brakes for road or the integration of mechnical shifting into the hydraulic disc brakes. Forget the shoes, the PRO bike parts or Pearl Izumi, right now it is all about Di2 for mountain biking.
The Di2 electronic shifting has already proved itself on the road and trickled down from Dura Ace to Ultegra so it is high time for the world of mountain biking to also reap the benefits. In some ways, mountain biking is already technologically advanced with disc brakes, front and rear suspension, some with electronic controls and remote dropper seat posts. Despite the different flavours of mountain biking and the harsh conditions under which the MTB drive train operates, electronic shifting was due to arrive sooner or later and Shimano knows where you will want to spend all of your pocket money this season… XTR Di2
Prototype Di2 front derailleur and crankset
New Shimano chainring and teeth design
The entire XTR component range has experienced a refresh and beyond mechanical shifting there are two key updates. Firstly the crankset has changed and there is the ability to change the configuration to run a single front chain ring (1x), two front chain rings (2x) or if required, three (3x). With Shimano XTR positioned as the top level performance groupset, it provides the opportunity for competitive bikers to configure their gearing to suit the ride. The teeth are also redesigned, slightly higher and thicker to better hold the chain and reduce dropped chains. The new chain is also directional and is the same chain that is now used for Dura-Ace on the road.
The long Di2 battery also connects to Fox iCB suspension
The Di2 electronic shifting is the other key update and the most obvious difference to Di2 for road is the battery looks like a bike pump and also mounts like a bike pump under the water bottle cage. While there is an option to have a seat-post battery, the engineers in Japan decided that the proliferation of hydraulic seat posts makes this less than ideal. Di2 for mountain bike has two programmable thumb shifters for shifting up and down which are quite intuitive and provide precise tactile and audible feedback.
Prototype (Demo) thumb shifters for electronic shifting
XTR Di2 display
Just as with Di2 for Dura Ace and Ultegra, Di2 for XTR trims automatically (front and rear) so when properly set up, it eliminates manual trimming or even misaligned gears that that can plague mechanical shifting. And the Syncro Shift means you can completely ignore the concept of front and rear derailleurs, instead you shift up, you shift down and the Di2 changes the gears seamlessly up and down. Shifting follows a predefined (and programmable) pattern but as a rider it means you can remove the left hand front derailleur shifting and leave the right hand do all of the shifting. It free’s up space on the handlebars although there is a digital display that is required.
For test riding the unsculptured, unbranded rear derailleur prototype
The whirr of XTR electronic shifting in Australia is currently on show by Shimano, however only with a prototype / preproduction demo version. It is connected to the Fox iCD suspension to demonstrate the integration capabilities. Together with the suspension integration, the battery life is estimated at 300 hilly kiliometres and more without the suspension. In practice, the electronic shifting is predictable and precise, the gradual step ups and step downs seamless. The sound of the electronic shifting, while only a peripheral, will still change the landscape of mountain biking.
Taking a backseat to the XTR Di2 was the Shimano 105 groupset upgrade. Ever reliable and widely regarded as the entry level groupset for road cycling, 105 benefits from the Dura Ace and Ultegra trickle-down effect.