I've now been through two Microspline setups on a reynolds hub. The first was set up by Fezzari before they shipped the bike to me. It failed within 3 weeks of daily riding. I warranteed it through a LBS in Tucson, waited 3 weeks, and got a new setup. It was good until yesterday. It failed during a climb and I walked 5 miles out of the trail. I will contact my LBS here in Southern Utah, hoping for a replacement, but I think after 40 years of riding Shimano.... I'm done. I have a 1988 Bridegstone with Deore on it (never a problem), and a 1996 Specialized Stumpjumper with XT on it (never a problem). I've had a hub problem with a 2019 hardtail plus bike with SLX, and now two problems with the XT on the Fezzari. Going to SRAM in the futureHi all, new to posting on the forum but have been reading product reviews on here for a while. I have had 2 of the new 12spd xt freehub mechanisms fail on me, and wanted to see if others have had the same experience. I built the hubs up to dt swiss xm481 rims with dt spokes as a solid set of trail/training wheels. I have had great success with shimano hubs in the past, so I saw no reason to spend more for a 350...
I'll start by saying the new design is completely different to the old system that has been around forever. Its similar to a dt, with 2 springs and separate freehub body that runs on cartidge bearings. The ratchet mechanism is self contained in the freehub body and is not user serviceable. the hub shell has cup and cone on either side. side note, the front hub is identical to the previous model.
The first failure happened within a couple weeks. I had the wheel off the bike, and it toppled over on the cassette side(hurts my soul to think about) and the cassette pulled the freehub out. At first I wasn't too concerned, thinking that they had finally copied dt swiss and made a tool free freehub. Then I realized that was not the case, as 2 small c-clips had popped out of place(one labeled DO NOT DISASSEMBLE) allowing the freehub mechanism to fall apart! I called shimano and explained what had happened. They were confused at how it fell apart, but walked me through how to reassemble it. After a few rides it started to creak like crazy(took me a couple weeks to figure out it was the hub), so I called shimano and they sent a whole new hub to my LBS under warranty.
I rebuilt the wheel with the new hub, and it worked flawlessly for 2 months. fast engagement, smooth bearings at a great price! really the goldilocks hub for 12spd IMO. Then it tried to lock on and turn into a fixie. I had just pedalled to the end of the driveway and started to coast up to a stop sign, when it made a god awful grinding sound that scared the sh*t out of me. I proceeded to lock the rear brake and slide to a stop. Upon taking it apart back at home, I found the toothed plastic spacer(think it is a tolerance thing) was completely chewed up. I think part of it must have gotten jammed in the ratchet mechanism. The two cartidge bearings in the freebody were also totally shot. I put every back together without the spacer, and while the freehub didn't lock on anymore, the horrible creaking was back.
Currently waiting on another warranty replacement, shimano maybe sending out an xtr hub. hopefully it doesn't break too.