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I fitted a new Shimano XT clutch rear derailleur to my trail bike two years ago when I built it up from new. I went for 1x10 setup using a 42 expander and a 32t n/w chainring. A year or so in and I started dropping the chain quite regularly. I replaced the chain, cassette, expander as well as the chain ring (which was quite worn given a poor chain line, which was corrected with the new chainring). Soon after this I'd occasionally still drop my chain. I shortened the chain to what was possible with the bike "fully compressed" in the lowest gear and all the air released from the rear shock. And frustratingly I'd still drop my chain (yes, the clutch was always engaged). Did a little google research and found that the clutch unit on XT and XTR clutch derailleurs could be adjusted by simply removing the plastic clutch cover on the derailleur and tightening the adjuster screw. The recommendation was to tighten in quarter turn increments given the derailleur's sensitivity to these adjustments. I was not aware of this prior to reading reading one of the articles. I removed clutch cover hoping that the adjustment would sort out my chain dropping issues. To my surprise the "cam unit" was broken (at this stage I did not know this part is called a cam unit)! This is the first time the clutch cover was removed and neither had I ever caught the derailleur against a rock etc. My first thought was oh fook, I need a new derailleur. Then thought of asking if any fellow hubbers had a trashed derailleur from which I could salvage the "cam unit". Then did a little more research only to discover that the cam unit (now discovered its name) commonly fails/breaks and can easily be replaced. I found the replacement unit on bike-components.de at the exorbitant price of EUR1.64. I ordered 4 units (along with a new campy chorus group set for my new road bike build...). Hopefully all arrives in the next week or two. Hopefully dropped chains will be a thing of the past as I honestly do not know how long I've been riding with a broken clutch unit. The derailleur still functions normally, just without the clutch. A pic of where the unit sits in the derailleur (sorry, pic's a little out of focus), the broken cam unit cage as well as the replacement part taken from the bike-components.de website. Hope my experience helps anybody else in trying to ID one possible reason for a dropped chain when using an XT clutch derailleur. Edit: changed bikediscount.de to bike-components.de

So the hype is big on the 1 x whatever drive train bandwagon....... I have been running a 1 x 9 for a little while and it has it's pro's and con's, the more dedicated drive trains with a narrow wide ring, clutch der and cassette with moerse big cogs certainly does have an appeal and makes sense ..............but ........... A chain ring does not last long, more so on a 1 x set up as you are only using the single ring vs sharing the wear on a dual or triple chainring crankset. Narrow wide chainrings are also not exactly a cheap purchase. So then, why not get a S/steel SS specific chainring for around the R350 mark and run the 1 x set up with the biggest moerse gear range cassette that works for you and then use a chain guide with a clutch der? Just thinking from an economics stand point here. Edit: Font size amended