Mountain Bicycle Patrol Takes a Ride on the Wild Side : Thousand Oaks: A group that repairs trails and the reputations of off-roaders celebrates its fifth anniversary with a grueling 3-hour trip.

For 150 or so mountain bikers, a Sunday ride through Wildwood Regional Park in Thousand Oaks went something like this: Slogging up dusty, rock-strewn trails only to barrel down treacherous descents with teeth and brake levers clenched before splashing through muddy creeks and sometimes ending up splayed out-- sans bike--in the chaparral.

“Mountain biking like this is a great experience,” said Peter Heumann, one of the cyclists celebrating the fifth anniversary of Concerned Off-Road Bicyclists Assn., a sort of Sierra Club for the knobby-tire set.

But this is not just another group of weekend warriors with a taste for danger. These cyclists work primarily to preserve bicycle access to trails in the Santa Monica Mountains from southern Ventura County to the San Fernando Valley.

The group also tries to educate others about safe and courteous riding. Some members run a mountain bike patrol through local parks to help other cyclists, hikers and equestrians by offering directions and first aid.

The group only rarely organizes social rides such as Sunday’s. Most of its time is taken up building new trails and patrolling old ones. They also lobby park agencies for more access to parkland over the objections of what Heumann calls “bicycle bigots,” people who don’t want bikers anywhere in the parks.

It can be a tough sell since mountain bike riders often are seen as the reckless terrors of the Great Outdoors, wildcats who tear along designated trails and sometimes veer off to rampage over the vegetation.

Riders Sunday were on their best behavior.

“We’re going to stop and smell the flowers occasionally,” group leader Joe Dillman shouted to a group of cyclists before departing on a three-hour ride through the Thousand Oaks park.

It turned out to be the first of several half-truths about the ride. About the only times anyone stopped to smell or even look at the vegetation was when one rider happened to make a wrong move and got thrown from the bike--a relatively common experience.

No one was injured. Had they been, they would have been in capable hands. About 80 members of the off-road group are also volunteers in its mountain bike unit, which patrols trails between Sherman Oaks and Point Mugu, providing mechanical help for broken bikes, medical help for broken bones and directions for broken compasses.

The ride had its ups.

“This is intermediate?” some riders complained as the line of bikes creaked and groaned up a trail akin to Donner Pass railroad ledges. Along one ascent, Heumann muttered another of the day’s half-truths when he told riders that they were almost to the top. But the summit was several hundred grueling yards away.

And the ride had its downs.

“It looks doable from here,” biker Adrian Tarlow said, scanning the rock-strewn trail that dropped off sharply just inches from her front tire. Then, turning to the rider who would go first, she said: “Well, you’ll be my barometer.”

Both made it safely to the bottom, their back tires skidding most of the way.

Careful, controlled descents are one thing that group members stress as part of considerate riding. They complain that gonzo riders who barrel out of control around blind corners give all mountain bike riders a bad name.

One of the favorite shirts among the riders depicted a bicyclist racing wildly downhill. The picture was surrounded by a red circle and crossed by a slash with the words “No Gonzo” printed above.

“A lot of people don’t know how to get off and walk their bikes,” said Frank Padilla Jr., a state park ranger who supervises Point Mugu State Park. “But our parks are not race tracks.”