Bouldering was once a sport of strategy and strength. Now a new movement is pushing it to hazardous heights.

HAD THERE been an orthopedic surgeon on hand for the Colorado premiere of the climbing film Scary Faces, she would have been handing out stacks of business cards. The crowd that December night at the Boulder Theater included a man in a wheelchair with two broken ankles, a pair on crutches, and a handful of others with pronounced limps. All were apostles of "highballing," rock climbers who used to boulder, or climb horizontally within ten feet of the ground, but who now scale bone-breaking heights of up to 30 feet, with foam pads and spotters strategically arrayed below to cushion and direct their falls.

"If pads had never been invented," says Paul Lembeck, a 40-year-old horticulturist who tore his ankle ligaments after falling 15 feet off a boulder last November, "people probably wouldn't be out highballing very much." The sport seems to be thriving under a twisted, crash-test-dummy logic: Give drivers air bags, they just go faster; give boulderers pads, they just go higher. More than a dozen companies now make over 40 foam models, and climbers from Squamish to the Shawangunks fear bouldering will forever change from a sport of strength to one of nerves—and good insurance.

Naturally, highballers love the thrill. "When you top out on a highball," says Michael Moelter, 22, "you're so psyched you didn't wreck. It's rad." But the sport is dangerous. Take Steve Banks's word for it. As head of the Venice, California­ based gear firm Pad Industries, one of the manufacturers that helped stoke the trend, he discourages highballing. "The higher you climb, the better chance you have of missing your pad," he says. "That's just good math." —Carol Greenhouse

It's What's Inside That Counts

After a century of service, say so long to the inner tube

"THIS IS GOING to be the big-time standard in every mountain-bike wheel out there," gushes Steve Driscoll, marketing manager at the French component manufacturer Mavic. He's not talking up a tweak on the rim or a novel twist in the spokes, but something more fundamental: a new generation of wheels that do away entirely with that 113-year-old fixture of cycling, the inner tube.

Driscoll has good reason to be pumped. Like similar designs available from competing wheel manufacturers Rolf and Bontrager, Mavic'stubeless Crossmax UST ($799) and more affordable Crossroc UST ($350) are less vulnerable to pinch flats, or "snakebites," the holes that occur when a rider slams his wheel into a rock or log, squishes the tire, compresses the tube into the edge of the rim, and tears the rubber. Converts will also be able to ride on as little as half the air pressure, doubling the amount of rubber on the trail and, by extension, the traction. This spring, tires from Continental, Geax, and Specialized, with unique treads arranged for low-pressure setups, will be widely available for the first time. "Tubeless will have as much impact on the industry as front suspension did," promises Specialized product development manager Al Clark.

Maybe. Bontrager founder Keith Bontrager believes that for now, at a steep $799 a pair, his firm's Race Lite Tubeless wheels will appeal primarily to pro racers. "The product reviewers are saying, 'I smashed the hell out of the rim, but I never got a flat,'" he says. "That doesn't work for the general public." Aside from bringing the prices down to earth, engineers have a few other kinks to work out. With their thick sidewalls, the new tires are heavier than their tube-bearing predecessors. Grit can sneak into the seal between tire and rim, allowing air to seep out. And at low pressure, front tires can fold and crumple during hard braking. But then, better the tire than you. —Ben Hewitt