Stiffness/Power Transfer
This is definitely the downfall of this shoe. It’s among the most flexible outsoles we’ve seen in a high-level Enduro shoe and this is quite noticeable on the bike, especially out of the saddle. While the hot-shot descenders will appreciate this, the Enduro racers will have a tougher time in the climbs. But the shoe’s fit is excellent and there was no heel or forefoot slippage during intense efforts, which helps in this category.

Fit/Comfort
What the M163 lacks in efficiency it makes up for in comfort and fit. The shoe hugs smoothly around every contour, and can be locked down tightly without discomfort. When it’s locked down, you’ll know it—there’s no play anywhere, but it somehow remains very comfortable all around. It’s a bit narrow at the toe but that didn’t even bother testers with a wide forefoot. Even testers with tiny heels found they stayed put under load. That lack of stiffness is actually a big benefit in hike-a-bike sections, as the highly-grippy outsole wraps around uneven terrain without causing cramping like many stiff shoes can. 

Closure System   
Featuring the standard two Velcro straps and a ratchet buckle on the upper, this shoe sets itself apart a bit with the reverse center strap and off-center tongue. Pulling from the outside in, this extra-wide middle strap can be seriously cranked without pinching, and it’s a more natural movement so it’s easily done on the fly as well. The only issue is if your foot is lower volume, you may have some excess strap clicking on your crank arm (but this can be easily trimmed off). The buckle, as is so common at this price point, features no micro loosening, which is not a big deal but a definite pain when it’s been over-cranked. Worse yet, this one only offers single-click tightening. But it’s a light and low-profile buckle, and it holds tight when closed.

Construction/Versatility
This shoe features a sort of hybrid construction, combining some Trail and some XC characteristics, which makes it a highly versatile shoe, and tougher than typical XC shoes. Tough, rubber reinforcements surround the toe and heel and the upper material is thick and also reinforced outside the toes where bashing rocks and trees is common. But it features the lower profile of a more XC style shoe, and is not too overbuilt for this type of riding. 

Off-Bike Performance
This would be an outstanding hybrid if the outsole weren’t so flexible, but that’s what makes it so great off-the-bike. It walks naturally and comfortably, with plenty of stick and great flex. And even for XC riding, or better yet, marathons, it’ll make the inevitable hike-a-bike sections—especially over anything wet and slippery—much faster and safer.

Breathability/Drainage
Wide vents on top will allow water in when crossing a creek, but they’ll also allow for a good bit of drainage. Plus, since there’s no cover over the cleat bolt underfoot, other than an insole, water drains here as well. Plus the upper has some slats and perforations over the instep and midfoot, which adds to ventilation and breathability. Overall these are surprisingly good for a burlier shoe.