Gear Review: Dynafit ZZero 4 C-TF/PX-TF Alpine Touring Boot

These alpine touring boots fit all are testers superbly and is comfortable going up or flying down.

Our tester, who wore the ZZeros for everything from cat-skiing powder in the Colorado Rockies to a multiday tour across the wind-raked hardpack of Norway’s Folgefonna Glacier, called them “the only boots I’ve liked equally going up and going down.” The fit had all testers gushing (a rarity). “It’s snug but forgiving, and didn’t pinch my wide feet,” says one.

Excellent ankle mobility, thanks to an easy hinge point and buckles that allow you to loosen way up without disengaging, made them all-day comfortable for touring. Yet on the downhills, the ZZero is one of the stiffest, most supportive backcountry boots we’ve ever skied, thanks to rigid carbon strips (called “powerstringers”) that run from the instep past the ankle and up the calf on both sides of the shell.

The shell, cuff, and tongue are all made of stiff Pebax plastic and “the overlapping shell and four-buckle system made them ultraresponsive and supportive on the descent,” says one tester. And a female tester couldn’t stop raving about the climbing comfort and downhill performance of the PX-TF, a lighter women’s version. “I’ve waited years for a boot that my bony ankles and high arches can tolerate all day, but that also charges hard on the downhill,” she said. Both versions come with a heat-moldable Thermoflex liner, a grippy outsole that provides great traction over rocks, ice, and dry trail conditions, and a forward lean that adjusts to either 15 or 20 degrees. ZZero 4 C-TF: $750; 7 lbs.; (27.5); 22.5-30.5; ZZero 4 PX-TF: $650; 6 lbs. 2 oz. (25.5); 22.5-27.5;