Comfort

The most noticeable feature of the Peak II out of the box is the lush inviting inner: super soft material all around, with bonded seams to minimize potentially abrasive stitching. The slightly padded, gusseted tongue secures the foot and keeps the tongue centered—although it could use a bit more padding under the laces to allow for tighter lacing without pinching.  The combination provided a snug, slipper-like feel with no noticeable hot spots throughout the testing.

Weight & Speed

At 9.6-ounces (men’s size 10) the shoes are not ultralight relative to this category, but certainly light enough to feel really fast and nimble, while also offering some protection. They are certainly race-worthy: best on smooth dirt trails, even with short sections of pavement, but also okay for slightly technical routes where the extra protection will justify the few additional ounces.

Cushioning

With a medium-drop design (17mm-8mm), and low-to-the-ground profile, there was still enough EVA foam for decent cushioning in the heel and midfoot for light heel striking and worry-free midfoot striking.

Agility

However, despite their comfort and quickness, two testers had the same major complaint about the Peak II: In unpredictable terrain they feel squirrely and unstable. Like many race shoes, the minimal structure in the upper allowed our feet to slip sideways violently in uneven terrain, like landing on the side of sharply angled rocks. Combined with the narrow-profile outsole, this became particularly problematic in loose gravel like volcanic rocks, where the highly uneven and unstable surface caused my feet to rock violently from side to side.

Despite the instability, the Peak II offers a very comfortable, tactile ride, over a wide variety of terrain and even pavement. The thin forefoot plate was surprisingly flexible and worked well at the front of the metatarsals, but stopped a bit too short to protect under the rear of the ball.

Traction

Traction on the full carbon rubber (softer and stickier, but lower durability) outsole was solid over most terrain, considering the low-profile design. Tiny knobs on each lug added grip on the slick stuff, and the shoe’s impressive flex—even in the thermoplastic support bridge under the arch—allowed the foot to wrap naturally around obstacles, improving traction. And mud and moisture seemed to have little negative effect.

Fit

Fit on the Peak II definitely runs about a half size small—I’m usually a 10.5 (11 in brands that run small) and I needed every inch of the 11. There’s a wide toe box and slightly narrower but well-padded heel cup.