Updates to the new 12-speed groups have been thoroughly appreciated but I have discovered a Shimano XT8100 issue. During my inial review last year I gave high praise to the new group – Review: Shimano XT M8100 12 Speed – A Sram-turnative. Since then I’ve mostly enjoyed being back aboard Shimano. Unfortunately, I have started to experience a derailleur clutch issue that isn’t necessarily new to Shimano derailleurs. This problem is one that I’ve discussed with others running 12-speed XTR 9100 and SLX 7100 so its not just the new XT that’s experiencing this.
After around 700 miles I mostly stick with my initial glowing review except with this one quirk. After approximately 350 miles I began noticing a noise coming from the derailleur as I shifted into the largest cogs. The shifting performance was only slightly sluggish at that point.
During the next ride as I shifted into smaller cogs, the chain drooped down towards the ground. The derailleur cage was still in its extending position from being in larger cogs. Shimano has had these issues on previous generations, but they normally don’t appear till many more miles and or after dirt has entered the clutch mechanism.
After taking off the clutch cover to see what the issue might be I found zero dirt but not much if any grease. I injected a little grease in the clutch, but that didn’t seem to help so I called Shimano to discuss. They gave the old standard warranty reply sounding like its the first time they’ve heard of the issue. The conversation ended by them saying that they would ship out a new one though.
After 2-300 miles on the new derailleur, the same problem came back. This issue can pop up within a ride and starts as a creaky noise when shifting into large cogs. Then the cage starts to not return within a very short period after the noise begins.
I was able to fix mine with some minor maintenance and all seems well after another 100 miles are so. What I discovered with both my derailleurs is that there was minimal to zero grease on the clutch. The below video gives some excellent insight into the issue while detailing the fix.
Since my derailleur was new and the clutch was clean I decided to skip some of the above steps. I simply removed the clutch cover and injected grease between the clutch band and adjustment screw. So far it’s working like new after several rides. I remain optimistic that the service might give more trouble-free miles since this issue was likely due to minimal grease from the factory.