Shimano Shadow Plus XT Derailleur: Quick Test- by Guitar Ted

Shimano’s workhorse mountain bike gruppo, Deore XT, has gone 10 speed, of course, (we tested the first DynaSys version here), and is being refined even further. The latest iteration of Deore XT now sports an innovation in rear derailleur technology that has me thinking, “Why hasn’t someone done this before now?” Well, at least it has been done! ;) What is all the fuss? Take a look after the image to see….

The “Plus” stands for the clutch mechanism that Shimano has integrated into this derailleur. (See the round shape under the “Shimano” logo on the derailleur? That’s the clutch cover.) This trickles down from Shimano’s XTR level, and looks to be a feature on several 2013 bikes spec’ed with XT and SLX component groups. (Yes- SLX will also get Shadow Plus) The clutch mechanism stabilizes the cage assembly so that when you hit some rough stuff, the cage doesn’t flop up and down in reaction to the trail, which causes chain slap, and on some 1X equipped bikes, chain derailment. (Of course, that has spawned a whole chain retention device market to solve the problem, but that’s another story…) Shadow Plus may not eliminate chain retention devices, but it will go a long way toward that end, perhaps, and at the least, will make mountain biking nearly as silent as riding a single speed.

The XTR version


I’ve been riding the XTR and XT versions of Shadow Plus for a couple of months now. The addition of the clutch mechanism has made the derailleurs slightly heavier than their non-Plus equipped versions, but the benefit is snappy shifting, and an “oh-so-quiet” ride. To my mind, the latter is the biggest advantage here. In fact, I cringe now when I ride a bicycle with traditional derailleurs over rough terrain and here the chain clattering on the chain stay. Something I took for granted before Shadow Plus came along.

Did I mention “snappy shifting”? Well, maybe I should say “authoritative kerchunk“instead. Unlike previous Shimano shift feel, where sometimes only a slight “snick” would be heard when switching gears, the Shadow Plus drops the chain into a higher gear with a feel and sound you won’t mistake for anything else. I suspect it has to do with the stiffness of the cage when the clutch is “on”. Oh…..yes, you can turn the clutch “Off”. In fact, you will want to remember to flip the switch above the Shimano logo to “Off” when you remove and replace a wheel. (On the XTR Shadow Plus derailleur shown above, the switch is anodized orange.)

Interestingly, the clutch mechanism is also adjustable, so one could tweak the level of resistance that the cage has to movement when the clutch is engaged. You will also probably need to periodically adjust the clutch due to wear. I’ve noticed mine have gotten freer movement with time on the trails. Oh yes….you’ll have one more thing to maintenance as well. The clutch mechanism will need cleaning and greasing from time to time.

Conclusions: Shadow Plus may be slightly heavier, need more maintenance than standard derailleurs, and is louder when shifting into higher gears, but the silence is golden ride over the rough stuff is really attractive, while the promise of better chain retention is also realized. Shifting is typical Shimano precise and fast and the typical Shimano build quality is retained, thankfully. Overall, I see this as an advancement in mountain bike componentry, and the quick trickle down to STX will make this a widely appreciated advancement as well. I wouldn’t go pitching the chain retention device in the parts bin just yet, but this technology may prove to be perfect for some folks 1X set ups. Good stuff here and it gets my thumbs up.

NOTE: Shimano provided an XT Shadow Plus rear mech and 10 speed DynaSys shifter for testing and review at no charge to Twenty Nine Inches. The XTR Shadow Plus rear mech was spec’ed on our Fuji SLM LTD 29 test bike and was included on this review. Fuji and Shimano has not paid, nor bribed us for these reviews and we always strive to give our honest thoughts and opinions throughout.