Mountain bikers, long vilified as unruly renegades, are finally winning respect — and regaining access to trails. But does a new generation of gonzo riders threaten it all?

On a bright blue-sky morning in June, the cinnamon-colored hills of the Marin Headlands, north of the Golden Gate Bridge, are just starting to heat up. I’m pedaling hard to keep up with Jacquie Phelan as we climb up the backside of Mount Tamalpais. Phelan, a longtime bicycle advocate and former United States dirt-racing queen, is giving me an up-close and dusty tour of mountain-bike history.

Every greasy bike-shop kid in America knows the story of how "Mount Tam" gave birth to the mountain bike. Back in the mid-1970s, a pack of hippie bike riders salvaged old Schwinn paperboy bikes and retrofitted them for the mountain’s rough dirt roads. Mount Tam’s "Repack Hill" was the testing ground for the sport’s pioneers. Legend has it that the steep route got its name because riders had to repack their drum brakes with grease after each speedy run.

Phelan was one of the first women to join the Marin mountain-bike scene. In 1980, she took part in the annual Thanksgiving Day ride — the "Appetite Seminar" — on a girl’s 5-speed town-bike. She soldiered through it and was hooked. She started racing the next year, winning her first national championship in 1982. Phelan held her title until 1986 and continued racing well into the ’90s. Now 50 and a survivor of breast cancer, she is still an astounding climber, capable of putting this writer, 21 years her junior, to shame.

Phelan is out ahead of me, threading her wheels along the best line up the dusty hill. I call out and ask the name of the trail.

"Fire road," she says over her shoulder. "I’m really going to have teach you to say ‘fire road.’ This isn’t a trail."

The distinction has more to do with politics than with anything else. In Marin, nearly every narrow trail — "singletrack" in bike lingo — has been off-limits almost since Phelan started riding here. And therein lies the other side of the mountain bike’s creation story: With mountain biking was born a new kind of controversy on the trails, one that has only deepened today.

Surging up another steep, rocky road, Phelan tells me that the early riders never imagined that the sport would catch on the way it did. "We thought it was going to be the world’s biggest small sport," she says. But by the mid-’80s, the fire roads and trails on Mount Tam were jammed with cyclists. Soon other users were complaining that the bikers were destroying trails and scaring horses and walkers.

What followed became known as the "hiker-biker wars." Hikers and horseback riders denounced mountain bikers as reckless and rude thrill-seekers, and fought to ban them from the trails. Some bikers, in turn, labeled the un-wheeled "HOHAs," an acronym for "hateful old hiking association."

As complaints and confrontations mounted, the Marin Municipal Water District, which manages most of Mount Tam’s trails and fire roads, began cracking down. Rangers hung surveillance cameras in trees and used radar guns to clock bikers’ speeds. Phelan got two tickets for being on off-limits fire roads, and her husband got a speeding ticket for going 22 mph. Bikers still recall those "police state" days as if it were a real war: Cyclists worked under cover of dark, running illegal midnight singletrack rides.

By the late 1980s, the Marin fight was boiling over just as mountain biking was spreading up and down the West Coast and inland, to Moab, Boulder and Durango. The national media picked up on the story, casting mountain bikers as adrenaline-addled rebels. A 1987 Newsweek headline dubbed them "Two Wheel Terrors." Two years later, the Wall Street Journal blared, "A New Menace Lurks in the Wilds: Supersonic Cyclists."

The hiker-biker wars peaked in 1993, when rangers discovered a secret trail that bikers had blazed illegally through the woods. Bikers called it the New Paradigm Trail, a protest, they said, against a system that wouldn’t take them seriously. But land managers, hikers and horseback riders saw the trail as proof that cyclists were out of control. That sentiment helped fuel a backlash against bikes.

Local mountain bike groups and the new International Mountain Bicycling Association (IMBA) were in the midst of a lawsuit against the National Park Service, which had locked bikes off all singletrack and even some fire roads in the new Golden Gate Recreation Area. Ultimately, the Sierra Club joined the fight, siding with the Park Service. In 1994, not long after the bikers lost the case, the New Paradigm Trail was destroyed with much fanfare.

"I don’t know if we failed," says Phelan of the New Paradigm imbroglio, pausing at the old trailhead on a flat section of fire road. The experience spurred bikers to become more of a political force, she says. Nationwide, bikers have become aggressive trails advocates and savvy participants in the public process. Local bike clubs volunteer thousands of hours building multi-use trails, work with land managers to open trails, and field homegrown bike patrols to make sure their fellow cyclists are following the rules. Last year, IMBA, which now boasts 32,000 members, patched up differences with the National Park Service, signing an agreement to introduce new mountain bike opportunities to parks across the country.