Gear Guide 2012: LOWA Khumbu II GTX Boot

A supportive and protective heavy-duty boot that keeps your feet cool with excellent breathability.

[most breathable]

Heavy-duty boots, with their myriad layers of protection and support, have a common flaw: They tend to be hot. Not so with the Khumbu, thanks to a unique combination of fabrics in the upper: a thin, breathable Cordura nylon overlaid with a plastic polyurethane mesh (holes are the size of a pencil tip). Compared to other waterproof boots with thicker and more densely woven fabric uppers, the Khumbu allows heat to escape more easily through its Gore-Tex liner, yet it doesn’t sacrifice big-boot protection.

“Through slushy snowfields and over scree-filled passes, my feet never got clammy,” said one tester after a summer trip along Colorado’s Highline Trail. The toebox and sides are fortified with split-grain leather over the fabric upper, while V-shaped side cutouts promote venting. Testers reported the fabric upper also made the boots feel light on the feet and increased stride comfort. “I liked the balance of flexibility and protection,” says one tester. “They’re stiff enough to sidehill up mountain slopes, but the slight rocker* allows a natural gait on groomed trails.”

The Vibram outsole has blade-shaped lugs on the heel that gripped “like a tractor through loose shale and on narrow, exposed, rocky paths,” says another tester who wore them in Colorado’s Pikes Peak Wilderness. Gripe: Two testers complained that the stiff tongue tends to shift around and is too narrow to provide adequate cushioning for the lower shin. Fit favors high-volume feet. $250; 3 lbs. 15 oz.; m’s 7-14, w’s 5–10.5; lowaboots.com

*ROCKER Heel to toe curvature of the sole that encourages easy striding and a natural gait