Our Take When mountain weather was changing rapidly, we reached for the Reactors for their superior traction across a wide range of conditions. Deeper-than-average 4.5mm, trapezoidal lugs on Michelin’s Wild Dig’R Descent outsole—with a pattern based on its line of mountain bike tires—dug into mud and loose gravel like cleats, and shed debris just as easily. The rubber compound kept us glued to packed snow, talus, and granite slabs. Although they’re fairly light, the Reactors perform like a heavier boot. Thick, above-ankle cuffs and a rigid, PU-coated foam upper offer excellent support, and felt at home on a class 4 scramble on Colorado’s South Arapaho Peak. Our tester also backpacked in the Reactor with loads up to 50 pounds. Note: The Reactors run large, so consider moving down a half size.
The Details Two hundred grams of Under Armour’s Reactor insulation kept our tester’s feet warm into the low teens, while a waterproof membrane locked out snow. The dual-density EVA midsole contains circular inserts (made of a proprietary foam) in the midfoot and heel that took the teeth out of rocky terrain. “I had no foot fatigue over an 18-mile day through ice, snow, and mud in Colorado’s Elk Mountains while wearing a daypack,” our tester reports.
Trail Cred “The insulated upper breathed really well while I was slogging through wet snow and rain,” one tester says. “I had no problems with sweating, and my feet were warm and dry during hikes when I was moving fast."