Shimano XT RD-M8100-SGS Rear Derailleur [Rider Review]

Our "Rider Review" article series features the honest reviews from verified purchasers of Worldwide Cyclery. They contain the photos, thoughts, feedback & overall review you are looking for. 

Shimano may have been a little late to the 12-speed party but now that their hand is finally in the game, we have seen tons of riders switching over from SRAM. Some people just have a better time on the Japanese brand and are dedicated to running their products over anything else. The 12-speed lines from Shimano proved to be fierce competitors against the beloved SRAM Eagle drivetrains and are equally just as popular. Our good friend Larry recently put on a new XT Derailleur, lets see what he thought.

Larry's Review:

The Shimano 12-speed drivetrain has been on my list of wants for a couple of years since its release. On a previous build, it was in the plans but was eventually replaced on the build by SRAM as Shimano parts availability was nonexistent. I will qualify here that my few years on SRAM Eagle drivetrains were trouble-free. I was very impressed with the shift quality and parts' longevity. I have always been a big Shimano drivetrain fan, however, and was really looking forward to trying out their latest drivetrain iteration knowing they purposefully make careful refinements.

Recently I purchased a Shimano XT RD-M8100-SGS Rear Derailleur to complete my SB130 custom build. I choose XT as it comes with all the shift quality of XTR, minimal weight penalty, no carbon on the cage, and a solid price. The riding here in Texas is rocky and technical and filled with tons of awkward, narrow gaps that love to find your rear derailleur. Therefore I wanted the most robust option over maximum weight savings. I paired this with an XTR M9120 cranks, XTR chain, XTR shifter pod, absoluteBLACK oval Hyperglide chainring, XTR 10-51 cassette, and Shimano Optislick cables and housing. Installation and setup did take some careful reading of the manual to get everything dialed to spec but was nothing too difficult.

Working for a shop as a mechanic for a few years had me wanting to fall into the same old habits when it came time to install but flipping through the manuals prior to starting revealed a few differences.

Chain length and b-tension are the high points to pay attention to and once these details are addressed, the setup is straightforward and the shift quality is as clean and crisp as I’ve ever experienced. Sometimes clean and crisp shifting on the stand can become clunky on the trail. This was not the case, however, and I couldn’t be more satisfied with the shift quality on the trail as well. Shifts were quick, even when poorly timed, and lever pushes were met with a pleasant snap as the chain moved to the next cog.

Conclusion:

"Unfortunately, I have already tested the durability a couple of times with a few awkward spills on some slippery techy climbs. The edges of the derailleur show the resulting contact with the surrounding limestone, but the shift quality was not affected. Other than lubing the chain, I have only adjusted cable tension after about a week of riding once everything settled in. Everything else has been solid and steady. I have read about the possible issues with the clutch seizing, so plan to keep up maintenance there and look forward to much more riding on this setup. As always, Worldwide provided an excellent experience purchasing and fast, trouble-free shipping! Any questions I may have are always promptly answered. These guys rule!" - Larry