XTR Di2 rear e-railleur
Shimano says its first mountain bike-specific Di2 rear derailleur is also its most technologically
advanced. The RD-M9050 features Shadow RD + stabilization that couples chain control with shift performance that doesn’t degrade over time, according to the company. They also promise seamless, instantaneous gear changes, as well as compatibility with any of the 11-speed front chainwheel options—1x, 2x or 3x. The RD-M9050 features Shimano’s signature narrow Shadow “q-factor,” keeping the mech tucked out of the way of mayhem. It’s also available in GS and SGS cage options.
Despite being electronic, the new Di2 rear derailleur retains XTR’s jewelry-like finish and form factor.
XTR Di2 front e-railleur
The front shifting on Shimano’s road groups has a well-earned reputation for speed and precision—characteristics the company says carries over to the dirt side as well in the new FD-M9050 front derailleur. Like the rear mech, the front derailleur is compatible with Shimano Synchronized Shift, and uses computer controlled auto trim as the chain moves up and down the
cassette to keep the drivetrain running smoothly.
Other than a little extra volume for its motor, the Di2 version XTR front derailleur looks fairly standard. The modular shifter bolts to adapters for any configuration—high clamp, low clamp, e-type or direct.
System batteries come with mounts designed to attach to water bottle bosses and nestle the battery next to a bottle cage. Like on the road side, we’re likely to see more integrated battery and wire accommodation inside frames and fork steerer tubes as manufacturers adjust frame designs to accept the system.
The XTR Di2 battery attaches to water bottle mounts.
While riders are sure to question the system’s robustness, Shimano points out that the road version of Di2 has fared extremely well in the poor weather of cyclocross, the European spring classics and even the winter-like conditions of this year’s Giro d’Italia. We at MTBR have also seen hacked versions of Dura Ace Di2 systems on mountain bikes that have proven to be sturdy.
Shimano XTR FAQ
Shimano sent us a handy FAQ that answers some of the questions likely to arise about both the new mechanical and electronic XTR groups.
1: Why did Shimano choose a 11-40 cassette to work with a single chainring setup? The range is too small.
Shimano’s philosophy for single front chainrings is that it is developed for dedicated use on specific courses. It doesn’t matter if you race enduro or XC, even with a wider range cassette it doesn’t cover the range of 2x or 3x. For all-round purposes it is better to choose 2x or 3x. This also results in better durability because the cassette is used more efficiently. We also chose to have all the gear steps below 15-percent so cadence changes are more gradual. This allows the rider to have more control in technical sections.
2. Can I modify the Di2 settings myself or should I go to a dealer?
With your charger for the internal battery you can connect the system to your computer and can change all the settings for the shifter, Synchro modes and multi-shift. Only if diagnostics reveal an error do you need to go to the dealer.
3. What happens if I crash on my rear derailleur? Is there a saver mode?
The Di2 rear derailleur is equipped with a saver or recovery mode to get you home presuming the mechanism is rideable—or at least as rideable as a damaged mechanical derailleur. Just push the button on the system display for three seconds to reset into the recovery mode.
4. What’s the weight difference between electronic and mechanical XTR?
It depends on your exact setup. Exact weights for the most common components are:
- Front derailleur (FD-M9070 D-type) : 115 grams
- Rear derailleur (RD-M9050-GS) : 289 grams
- System display (SC-M9050) : 30 grams
- Shifter switch (SW-M9050) : 64 grams
- Front derailleur M9050 Di2 is 5 grams lighter
- Rear derailleur M9050 Di2 is 68 grams heavier
- Shift levers M9050 Di2 is 36 grams lighter (if you just use 1 it is 136 grams lighter)
- Battery is 51 grams (extra item)
- System Display is 30 grams (extra item)
For the 2x setup with only a right hand shifter (Synchro mode) M9050 Di2 has the same total weight as M9000 mechanical (there is a 47 gram difference on components, but the wires are lighter then cables).
5. Is damaging the rear derailleur more likely with electronic?
Your chances of breaking an electronic rear derailleur are similar to mechanical. In case of a crash there is a saver mode that helps to protect the derailleur a bit.
6. Is the FOX iCD system fully integrated?
Yes, it’s even adjustable and compatible with the E-tube software.
7. Will Di2 XTR be super expensive?
It will be more expensive than XTR M9000 mechanical however it also adds a lot of features and advantages, and is easy to modify to your personal preferences. The price difference will be similar to the difference between mechanical Dura Ace and Di2 Dura Ace—about 40% more than mechanical for the full 2x setup.
8. When can we expect Di2 on XT?
So far we cannot say anything about that.
9. When is XTR Di2 available?
The fourth quarter of 2014.
10. What about wireless?
We present XTR Di2. What the future will bring regarding new products (even competitor) time will tell.