JAUNTS : Club Gets Bike Riders to Head for the Hills : Group’s weekend rides range from three-hour ‘jaunts’ to six-hour hill-climbing marathons.

They called it a beginner ride. A somewhat gentle jaunt in the Santa Monica Mountains for those new to mountain biking, or those who needed to get in better shape before tackling truly rugged terrain.

It turned out to be three hours and 15 minutes of sweaty up-and-down pumping in 90-degree heat. It was hills sometimes too steep to ride so the bikes had to be pushed up. It was a hairy ride down the side of a mountain. It was like a roller coaster--not exactly fun at the time, but well worth the adrenaline rush at the end.

The North Ranch Mountain Bikers club holds rides every weekend, usually in Ventura County. The A Team rides are for experienced riders in good shape who can wrestle with steep terrain for three to five hours. The B Team rides, on alternate weekends, are easier and shorter, two to three hours.

So it was a B Team ride that drew two dozen or so riders to Rancho Sierra Vista park in Newbury Park on a recent Sunday morning. About six or seven had never ridden with the group before. Some had never ridden off-road at all.

Their leaders were not twenty-something jocks. Joe Dillman, who organizes the B Team rides, is a snappy, 70-year-old, white-haired, semi-retired financial planner. Randy Rogers, 48, who leads the rigorous A Team rides, suffered a heart attack six years ago. But now he leads the pack.

The goal that day was to pedal from Rancho Sierra Vista eastward on the Los Robles Trail to a trail head near Lynn Road and Ventu Park Road. In single file, the group wheeled along the dirt path over the grassy meadows, eventually crossing West Potrero Road. At that point, a couple of riders dropped out, unable to handle the trail.

But the more rugged ground was yet to come. The shadeless trail grew steeper in places--not much of a problem for some riders. As it turned out, some were A Team bikers who simply do all the club rides. But for the novices, the hills meant getting off and pushing the bike uphill, almost as torturous as trying to ride it.

A few more riders dropped out, exhausted by the heat.

“This is for the thermally challenged,” Dillman joked. They stopped often for water and to wait for stragglers.

The riders wound up Rasnow Peak and down switchbacks on the other side, passing a couple of bikers--no hikers--along the way. When it was over, about a third of the original group had dropped out, and a few had taken spills and wore the dirt to prove it.

For those conditioned to the demands of the sport, the ride that day “not even slightly winded them,” Rogers said. “If you get into it and keep at it, you’ll be in better shape than if you join a gym.”

While the B Team rides are for beginners in reasonably good shape who have done a little riding, there are occasional C Team rides for what Rogers calls rank beginners who need some instruction. Once or twice a year, the group also holds a bike clinic to provide some technical know-how, along with a short ride.

Rogers formed the group in 1988 after he bought a mountain bike and sought the company of other riders. Then the club nearly fizzled out after he had his heart attack. “The doctor told me I would never ride again,” he said. After a year, though, he was back on the trail.

Membership now numbers nearly 200 bikers, with rides attracting up to a couple dozen.

The rides are free, but those who join the club get a biweekly newsletter with a riding schedule. It costs $12 per year, or $24 for both A and B Team newsletters and schedules.

Their rides have taken them to Lancaster, Mt. Pinos, Santa Barbara and Big Bear. Once a year they hold their Bikini Beach Ride from the Santa Monica Pier to Redondo Beach. (So-named because of the prize awarded for the photograph of the skimpiest bikini.) They get even sillier. At their annual pool party they stage crazy bike contests, like a 100-foot race in the lowest gear.

But they don’t do anything crazy on the trail. High-speed riding is forbidden. That’s what gets trails closed to mountain bikers and gives the sport a bad name, Rogers said.

Trails are not being closed off to bikers at the rate they were a few years ago, he said. “Bikers are getting the message to sink in.”

Details

* COMING UP: The North Ranch Mountain Bikers’ next ride will start at 8 a.m. Saturday in Tujunga at the Foothill Freeway and La Tuna Canyon Road. This is a B Team ride for beginners in reasonably good shape.

* GETTING STARTED: The club has a C Team ride for rank beginners with no experience at 8 a.m. July 16 in Wildwood Park, Thousand Oaks. Riders meet at the intersection of Avenida de los Arboles and Big Sky Drive.

* CLINIC: The club also has scheduled a clinic at 8 a.m. Aug. 14, at the south end of Moorpark Road in Thousand Oaks.

* CALL: For club information, call 373-8824.