And even as bikers convinced the BLM that bikes were different from off-road vehicles, a handful of mountain bike groups are increasingly adopting the motorheads’ tactics. In places, they even joined forces in their fight to keep trails open.

"IMBA likes to play nice and they got screwed all the way," says Chris Vargas, president of the Warrior Society, a small mountain-biking group in Southern California. The Warrior Society partnered with the BlueRibbon Coalition, the nation’s leading off-road vehicle access group, because its members felt that IMBA had failed to defend some of their favorite trails in the Cleveland National Forest during the Boxer wilderness negotiations.

Mark Flint, who serves on IMBA’s National Parks task force, is less outspoken in his criticism. Still, he’s started MTBAccess, a small Arizona-based mountain-bike group that has pledged to work with off-road vehicle groups. The Southern Sierra Fat Tire Association of Bakersfield, Calif., and a mountain bike club in Idaho have also allied with the BlueRibbon Coalition.

Perhaps due to the saber-rattling from local bike groups, IMBA has become more aggressive in its access fights. The group has a growing legal fund and recently hired its first paid state representative — not surprisingly, to work on access issues in California.

The group walks a fine line. On one hand, if it wants to attract the new generation of riders, it needs to push for more access for freeriders and downhillers. On the other hand, its older constituency (the average IMBA member is 37 years old) tends to be more reserved.

"We get letters from members who say they are pulling their membership because IMBA is trying to get into wilderness," says Dice, "and others who are complaining that we aren’t doing enough for access."

Even Gary Sprung seems to have some misgivings. "I’m not a big fan of freeriding and downhilling, only because it’s more about the bike than it is about nature," he says. "Its not the same as regular mountain biking. It’s almost like a different sport." Riders who build renegade trails "have caused some environmental impacts and made my job harder," he adds. "And it does not please me."

Rethinking bikes and trails

No one knows the tough position mountain bikers are in better than Garrett Villanueva. A civil engineer by training, Villanueva oversees 450 miles of very popular trail in one of California’s outdoor sports hotspots: Lake Tahoe. Villanueva constantly sees the damage caused by irresponsible downhilling and freeriding. He has photos of the jerry-rigged stunts he’s had to remove from national forest land. He recently closed "Jackie Chan" and "King Axle," two illegally built trails.

Villanueva has to deal with persistent access issues as well. A portion of the Pacific Crest Trail, which has been closed to bikes since 1988, runs though his area. Renegade bikers know it affectionately as the "Perfect Cycling Trail." The epic Tahoe Rim Trail has many sections open to mountain bikes, but a few are closed where the trail dips into wilderness areas. On the rare occasions Forest Service officials catch cyclists riding in wilderness, they confiscate a wheel and force the biker to walk out of the woods.

But while Villanueva often acts as the bike cop, he is also a dedicated mountain biker. He remembers how eight years ago, when he started working with the Forest Service, one of his superiors scoffed at mountain bikes as little more than a passing fad. Villanueva assured him bikes were here to stay. He was right: Mountain bikers are now the second-largest trail user group in the country, after hikers, according to the Outdoor Industry Council.

Villanueva has become the agency’s go-to guy for mountain-bike management. He travels the state consulting on trail design, in an effort to minimize damage. It’s not easy. The new high-tech bikes have opened up new stretches of trail deep in the forest. Older trails not designed for bikes have suffered the most, he says. On the Corral Trail, a 2.5-mile loop southwest of the lake, he estimates that years of use, much of it by mountain bikers, have displaced nearly 2,500 cubic yards of soil. That sediment contributes to the clouding of Lake Tahoe’s clear waters and impacts the local fisheries.

But Villanueva says he sees hikers and horse riders cut switchbacks too, and that locking bikes out is not always the best solution. Bikes only damage trails if the trails aren’t built properly, he says. He has redesigned trails like the Corral Trail, to armor them against knobby tires. Many of the newer trails, often designed with help from IMBA, could last as long as 50 to 100 years with regular maintenance, he says.

In his redesigns, Villanueva tries to make trails as fun as possible in an effort to defuse the temptation to build more thrilling, and dangerous, illegal ones. He knows that some bikers prefer taller stunts and teeter-totters, but on Forest Service land, he utilizes only natural features: logs, dirt mounds and boulders. "What we’re trying not to do is sanitize the trails. I think we’ve been guilty of that in the past," he says.

But the Forest Service, like many of the federal agencies, still has no official mountain bike management policy. The first step towards a plan is Villanueva’s next project: The California Mountian Bike Situational Assessment will catalog the current state of mountain biking on national forest lands in the state, from general usage to illegal trails. Eventually, it will serve as the model for a national assessment.