But despite the good intentions, mountain bikers can’t seem to shake their renegade image, especially in California. In Marin a few years ago, a leader of a local bike group was convicted of illegal trail building. Across the West, some riders build illegal trails and obstacles, and knowingly "poach" closed trails. A small body of scientific evidence suggests bike tires are no more damaging to trails than horse-hooves or hiking boots, but the technological advancements keep racing ahead, allowing bikers to go farther and faster, at times pummeling favorite trails.

Today, the "hiker-biker wars" are raging on an even grander scale, as a new generation of riders pushes the limits of what is possible on two wheels, and bikers fight for access to more trails. The issue comes to a head over the subject of wilderness.

The great wilderness debate

The 1964 Wilderness Act banned all forms of "mechanical transport" from designated wilderness areas. Bikes aren’t specifically mentioned, but land managers and many environmentalists argue that they’re obviously mechanical, and are simply incompatible with the "primitive recreation" experience that the law set out to protect.

If a bike is mechanical, so are oar-locks, ski bindings and even hiking poles, says Gary Sprung, who worked as IMBA’s communications director and national policy director until 2005. Keeping bikes out of wilderness is pure snobbery, he says: "There is a basic disdain for this form of transportation. It comes from this idea that hiking is saintly and the only way to go. They don’t understand that we can stop and smell flowers and feel the wind."

Sprung remembers the early days, before the crackdown, when riders rode free in wilderness areas like the West Elk Wilderness, above his hometown of Crested Butte, Colo. All that changed in 1984, when the Forest Service, the last of the federal agencies to respond to mountain bikes, banned them from all designated wilderness areas.

IMBA’s Web site states that mountain biking is "consistent with the values of Wilderness land protection," but the group has not pushed to allow mountain bikes in wilderness areas. Still, Sprung and former IMBA president Jim Hasenauer, two of the guiding intellectual forces behind IMBA’s wilderness stance, personally believe that bikes should be allowed into wilderness, though both agree that some areas are too sensitive for any humans to enter.

Although IMBA hasn’t pushed for access to existing wilderness, it has entered the debate over creating new wilderness areas, insisting that existing bike trails be left open, and that bike-friendly areas be designated nearby. And in the past two years, IMBA has come out swinging against Forest Service proposals to ban mountain bikes from areas the agency has recommended for wilderness protection in Idaho and Montana. "We have supported wilderness bills that have closed trails to mountain biking, and I know we will again in the future," says the group’s government affairs director, Jenn Dice. "Our position on every wilderness bill is that we want to get it to a place where we can support it."

But getting a bill to where IMBA can support it can be an excruciating experience, according to Dan Smuts, California regional director for The Wilderness Society. An avid cyclist who rides a mud-spattered Santa Cruz Blur to work, Smuts praises IMBA’s trail-building efforts, and believes that mountain bikers deserve a say in land-management decisions. But when it comes to wilderness, he says, they simply don’t belong.

Leaning over a pile of maps in his spartan San Francisco office, Smuts points to a line drawn around a proposed wilderness area near Donner Pass. California Sen. Barbara Boxer, D, included the area in a wilderness proposal she unveiled in 2003. "We moved the boundary to accommodate the Hole in the Wall Trail, knowing it was a very popular trail (for bikers)," he explains. Then he flips to another map of the Grouse Lakes and Castle Peaks areas. In return for keeping Hole in the Wall open, he says, IMBA agreed to give up access to these areas in order to protect them as wilderness.

But then, Smuts says, IMBA backpedaled, and requested that the land and a few trails be protected under a less stringent designation that would allow bikers access. Working with IMBA is "like negotiating with Jell-O," he says. "Nothing ever settles down."

During similar negotiations on a smaller California wilderness bill sponsored by Rep. Mike Thompson, D, IMBA demanded exemptions for one trail that had been off-limits to bikes for years, and another that was nothing more than un-ridable sand. The California office of The Wilderness Society eventually severed talks with IMBA, choosing instead to hammer out a compromise with local bike groups. (The bill, approved by the U.S. House of Representatives in July, goes to the Senate this fall. It is not expected to meet resistance from President Bush, himself a mountain biker.)