With the RD-M786 Rear Derailleur, Shimano has refined shifting in all trail conditions, borrowing features from last year's XTR group, while adding compatibility with new direct mount frames.
The direct mount system allows the derailleur to sit about 25mm further back than previous designs, where it's less exposed to impacts along the trail. It also creates a stiffer interface between the derailleur and frame and allows for faster wheel changes, particularly on bikes using thru-axle systems. A pre-installed B-link allows for back compatibility with traditional derailleur hangers.
Another new feature is the XTR-derived Shadow Plus stabilizer switch which can be enabled to increase spring tension and eliminate chain slap. The low profile design allows the cage to easily clear obstacles like roots and rocks, and a longer arm length results in great mechanical mechanical advantage, essentially giving the shifter more control over the derailleur spring for crisp, reliable gear changes. Sealed pulley bearings keep out mud, dirt and grime.
The Deore XT RD-M786 Rear Derailleur is designed for Shimano Dyna-Sys 10-speed MTN drivetrains/shifters. Available in Mid-Cage or Long-Cage models. Black or silver finish.
New derailleurs work best with new chains.
For whatever reason (I assume budget), my 29'er with full XT groupset did not come with the "Plus" version derailleur - meaning it was the XT derailleur without the 'clutch'. With my 29'er being a VPP design, the larger chain stays means the chain would get slapped around quite a fair bit. I am running a 2x10 drivertain, so I have not have any chain drops thanks to the FD, but the chain slap was unreal. The solution? I gave-in and bought the "Plus" version with a clutch. What an absolute difference it made! Not only was my bike considerably quieter, but shifting over rough terrain actually improved! I'm guessing the extra tension on the chain that keeps it from bouncing around helps 'stabilize' the tension of the chain between the top jockey/pulley wheel and the cassette, making tighter and crisper shifting over bumpy terrain. My advice for anyone looking at the Shadow Plus derailleurs: Do not even waste your time with the non-clutched/non-"Plus" version! These are night-and-day. My bottom pulley wheel is started to show a little wear on the teeth so it will need replaced soon, but that's too be expected. Overall, 5/5 stars. I could not be happier.
This derailleur works well, especially compared to other brands. It stays tight and is easy to adjust when removing your rear tire. It does occasionally skip on one of the ten gears, which can get frustrating, but there are several videos on youtube that show you how to easily maintain and tune this component. Keep it clean.
I haven't dropped a chain since getting this, but it isn't always easy to switch gears. During a couple of endurance races when my hands are fatigued it took some effort to push the gearing. Otherwise a great product.
You just can't go wrong with XT components. This derailleur performs in all conditions and hasn't let me down yet. The shifting takes a little getting used to as it is harder to push than a standard non-plus derailleur, but the reduced noise and chain slap is well worth the extra effort.
This is an excellent product. Don't waste your time with the "non plus" version unless you LOVE the sound of the chain destroying your frame. The plus system is excellent and the 10spd platform is perfect for 1x10 adventures.
No dropped chains paired with a raceface nw ring. Smooth shifting, reliable. I've heard about issues with the clutch failing but so far so good. I just keep a close eye on it. I've heard you can relube them if it looks like it needs it to help with the clutch issues.
The XT is in my opinion the best bang for the buck in the Shimano line. The clutch makes dropped chains a thing of the past
I purchased this derailleur to replace a SRAM X9 that had lost spring tension after a couple of years. The difference was night and day, the XT plus eliminated a lot of noise, and shifted reliably every time. There were no dropped chains or ghost shifts to speak of. After one year in service, I noticed that the shifting performance took a turn for the worse. I removed the clutch cover and found a broken piece, which controls the friction. Apparently this is a known issue with the "Plus" series derailleurs. It was replaced under warranty, so no hard feelings on my side. The shifting is now as precise as ever. Nonetheless, I have to knock one star off for durability.
Getting a Shimano "Plus" rear derailleur is easily one of the best upgrades to make these days. The clutch system is absolutely amazing. It completely silences the chain slap which is hard to believe until you try it. The Dynasys shifting is spot-on and very responsive. I'd recommend the medium cage if running this on a 1x setup.