Fat tires have been celebrated everywhere from Moab's slickrock to the labels on a Colorado amber ale. Way back when, the allure of off-road riding was born of necessity: when wood-frame bikes with metal tires appeared in the 1800s, the roads weren't paved so bicyclists were forced to bump along "off-road."

The modern tricked-out sport of mountain biking, however, sprung up from the dust in the early 1970s.

In-Bounds Biking   There was a time when the spring snowmelt brought the sound of silence to chairlifts around the land. Today, however, many ski hills are re-positioning themselves as year-round destination resorts, opening up their snowless ski trails to a new cadre of downhill addicts: mountain bikers. Here are some of the best: Whistler Blackcomb (British Columbia): 125 miles of lift-served terrain; 4,800 feet of vertical; three skills centers. More at www.whistlerblackcomb.com. Snowbird (Utah): Access to some 3,200 vertical feet of steep terrain from the high-speed Aerial Tram, dropping you and your rig atop 11,000-foot Hidden Peak. More at www.snowbird.com. Snowshoe (West Virginia): 120 miles of trails spread across 11,000 acres; lift-served Mountain Bike Park with some 20 technical trails. Read our guide to Snowshoe. Whiteface (New York): 2,500 vertical feet accessible from Cloudsplitter Gondola, plus gentler terrain along the lower valley slopes. More at www.whiteface.com.

Its true origins, though, are an ongoing bone of contention in MTB circles; whether it started with a group of hill riders in Crested Butte, Colorado, or the two-wheeler innovators of Marin County, California, riders from the different regions tend to champion their claim on fat-tire pre-eminence. (Crested Butte built the Mountain Bike Hall of Fame to bolster its credentials.)

Wherever it started, the fat-tire craze exploded in the 1980s as recreational riders scooped up the knobby-wheeled rigs to navigate local trails and professional bikers began gunning for higher speeds and tighter turns. Cross-country mountain-bike racing became an Olympic sport in 1996; other styles, such as downhill—timed races where bikers rocket down steep trails, screaming around turns and jumping off obstacles in their path—have also emerged.

These days, the buzzword is freeriding. "Freeriding is not about racing, it's about challenging yourself on harder and harder terrain," says Pete Webber, communications director for the Boulder, Colorado-based International Mountain Biking Association. This freeriding concept—which encompasses everything from technical trail-riding to incredible jumps, like Canadian freerider Dave Watson's leap over the peloton during the 2003 Tour de France—started on the steep tree-lined trails of Vancouver's North Shore. It's now taken off across North America and spawned a series of mountain-bike parks, with the cream of the crop at the Whistler Mountain Bike Park, which offers everything from slickrock routes to tabletop jumps. There's even a new bike park in downtown Seattle being constructed beneath a stretch of Interstate 5 where biking groms can hone their skills. Wherever you do end up hucking yourself and your wheels, look for the freeriding craze to blast off in the coming years.
Pioneer: Joe Schwartz

Growing up in the mountain town of Nelson, British Columbia, Joe Schwartz and his buddies naturally started to explore the mountains any way they could, mucking around on their bikes and drooling over the very first freeriding videos. Schwartz, 22, has turned those early adventures into a career, showing off his smooth, flowing style in the four New World Disorder movies and as a member of the Kona Clump freeride team. He's been picking up sponsors like a poison-oak rash, from local bike parts distributor NRG Enterprises to bike behemoth Smith, to fund his own mountain explorations.

When not cruising with film crews or the Kona Clump team to shred singletrack in spots like New Zealand and Morocco, Schwartz spends his summers in Squamish, British Columbia, working the steep drops at nearby Whistler. "I never get tired of it here," he says. He also gets a boost of fat-tire love from the kids he coaches at Whistler's week-long mountain-bike camps, where he stays on the lookout for squirts pulling BMX-style tricks like backflips and huge 360s, which he thinks are the next step in the freeride movement.

Actually, Schwartz would rather not call it that. On a recent trip to the States, he and his crew dubbed their adventure "Fun Riding." "I'd like to see that word catch on," he says. When the snow hits, he's back to Nelson for his other mountain fix—as an assistant ski guide for two local ski-cat companies.

If Schwartz is not riding on snow or dirt, he's probably cooking. He'll do pretty much anything, but as with his riding, it's hard to pin him down to a signature dish. "I'll save that for when I'm 50," he jokes.