Shimano's XTR Di2 RD-M9050 Rear Derailleur's coolest feature is definitely Shimano's Synchronized Shift system. You might think effortless, perfect-in-all-conditions shifting that's never compromised by wear and contamination would trump any entrant in this category, but, well, it doesn't. We even admit to being skeptical at first, since Synchronized Shift automatically shuttles your chain from cog to cog without any input from you, but the results of just one ride on this system speak for themselves. The RD-M9050 intelligently manages the fleet of cogs at the aft-end of your drivetrain.
By putting the rear and front derailleurs in communication with each other, Synchronized Shift can actually calculate your efficiency and perform simultaneous front and rear shifts to eliminate cross-chaining and set you up in the best chain line for any given gearing. These shifting patterns depends on the direction you're shifting and the combination you're shifting into, and they're also programmable via Shimano's E-Tube system, so you can set your preferences in advance to ensure that your internally-communicating drivetrain isn't conspiring against you.
Another category of big winners in the Synchronized Shift game are short cage derailleurs, which the system protects by making sure you never run out of chain when cross-gearing; it just adjusts the front and the rear to give you the gearing you want without tearing your derailleur off. Still, if you decide against Synchronized Shifting, then you can turn it on or off as your preference demands.
The shifting itself is peerless, as the derailleur always knows where it is, so its travel isn't restricted or lengthened by imperfect cables. It situates the chain squarely on every cog and it jumps between those positions with startling speed. No hesitation, no grinding. Ever.
As with other Shimano Di2 bits, the XTR rear derailleur is compatible with Shimano's rust-, stretch-, freeze-, and generally worry-free E-Tube wiring system. Its modularity makes it easy to set up on virtually any frame, though it does cohabitate with less friction when the frame is built with Di2 in mind.
- Synchronized Shift technology
- Shifting pattern can be programmed to your preferences
- E-Tube wiring system
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Reviews & Community
XTR DI2 = Scrap
- Familiarity: I've put it through the wringer
I've been a loyal Shimano XTR user for well over 20 years. DI2 finally changed that. I just ordered my first SRAM Eagle groupset. The idea of electronic shifting is great, and I love the DI2 for the road, but when it comes to mountain biking, DI2 is way too slow, with a lot of complicated double shifts, especially when you're on undulating terrain. I used my DI2 for just under a year -- maybe 1,200 miles. During that time, I had the another of the same frame set up with XTR mechanical. The performance and ride experience between the two was not even close, but I wanted to give DI2 a real chance, so I kept trying it. Last week, after racing the Tahoe Trail on DI2, I had my shop strip the DI2 and replace with mechanical derailleurs and shifters. Mechanical weighs less, it's faster; and you have more control of gearing -- and the constant beeping!! Yes, I am sure there's a way to silence it, but it drove me crazy and made me want to apologize to everyone else forced to listen to it. From the start I was annoyed with DI2's programming. I tried to have it reprogrammed to allow me to go to higher sprockets while on the small chainring. I was able to get an extra gear or two, but the thing was still constantly driving me to the large chainring. Then if you ever needed to immediately drop to a very low gear (maybe because you come around a corner and find a big obstacle or sudden hill), you've got to allow the computer to perform a bunch of shifts, including a front and rear simultaneous shift. Ultimately, the DI2 was allowing me to go through 4 or 5 sprockets on small ring. The rest was all large. If you're running that way, why even have a double? Shimano of course offers a single setup, but the range in the back is less than ideal for a larger rider doing endurance events, so, I started looking into SRAM, which offers a wider range with the Eagle groupset. It's on the way. This will be the first mountain bike I've ever owned without Shimano shifting, and I've owned a lot of them. Thanks, DI2, you suck!
Weight is wrong - per Shimano's site it's 289-292g http://bike.shimano.com/content/sac-bike/en/home/e-bike/shifting/derailleurs/rd-m9050.html
I want to run a 1x 40T front, 11-40 rear. Will a medium cage xtr work?
Yes, the medium cage works with single and double chainring setups with the current generation XTR.
Customer Account Manager
does this product ship to Australia and are the cables included?
Great for CX 1x
- Familiarity: I've put it through the wringer
Really happy with this RD. I have it on a CX bike set up with a 1x and it works really well. I had a DuraAce RD with a RoadLink but the XTR clutch handles the big range much better without any chain issues.
Super awesome !
- Familiarity: I've used it once or twice and have initial impressions
Have Dura Ace Di2 11-speed on the road steed, now rolling with it on my mt steed :) Total FYI - I am running a SRAM 10-42 cassette, SRAM chain, and SRAM Xo1 1X cranks with this - works flawlessly! I had many hesitations because I love the 1X drivetrain SRAM has to offer as well as the hill grinding 10-42 cassette. Setting up is waaaay easier then running cables, etc.
Only hard part is, that depending on your frame, where to put the battery and wires. Pre-planning wiring and battery placement is a must prior to install. I have a 2015 Stumpjumper FSR 650b and was able to locate the battery in in the seat tube, just below the dropper post. For the short runs of wires that are exposed, I used electrical shrink-wrap tubing for a super clean look.
Long term test to follow. I am familiar with the E-Tube set-up and set the rear derailleur to 'fast' - awesome. Also, if you run Di2 on your road bike, the front LED Display already has a junction box, so no need for that. Additionally - if you get the new FOX shocks, you can remotely actuate the shock setting with this stuff also - super crazy.