I was looking for a way to run lower gears on my 11-speed road drivetrain, and coincidentally, a new product just came out. It allows road brifters to work with an MTB rear derailleur and cassette. Very easy to install, and works perfectly so far. Had the bike out today on the Mount Vernon Trail, which is paved, but very twisty and hilly, so I really put the Tanpan through its paces on a 20+ mile ride.

The cassette is 11-40, giving a really nice low gear, without losing anything on the high end. I actually rode the entire time on the smaller chainring to simulate a 1x setup with a 34 on the front, and was able to ride from 5 to 24 mph comfortably, which is perfect for commuting. This will be my new setup on another bike, so it was a test to see how a 1x with 11-40 would do. Very happy with the result.

One nice benefit to the XT M8000 derailleur is the clutch, completely eliminating chain slap. I love a silent drivetrain, and all the root ridges and other bumps can really cause a lot of chain noise. It is slightly harder to shift with the clutch on, but I haven't adjusted the clutch tension yet, so that may not be noticeable if the tension is lowered.

Here are some pictures from the first test ride.