Fat- Tire Fun

As anyone who has spent any time on San Fernando Valley streets knows, you don’t need a mountain to ride a mountain bike. Sure, it helps to live adjacent to the Santa Monica Mountains, which offer hundreds of miles of trails for bikers. But knobby tires are just as comfortable in an urban setting as they are on mountain trails. And they’re getting more popular every year.

Mountain and mountain / road “hybrids” account for about 90% of the bicycles sold in the U.S. According to the National Sporting Goods Association, the number of on-road mountain bikers in the U.S. increased 16% from 1994 to 1995, while off- road mountain bikers increased 1%. Urban riders are increasingly relying on their bikes’ strudy treads to tackle bumpy city roads.

Whether on- or off-road, mountain biking requires certain skills and etiquette to keepriding safe as well as fun. Safety is especially important on the Valley area’s many multiuse trails, where bikers are likely to encounter hikers and horseback riders.

Sticking to the 15 mph speed limit on trails in the Santa Monicas is one way bikers can make themselves more welcome in the mountains, says Mark Langton, who teaches skills classes with CORBA (Concerned Off-Road Bicyclists Association). “Give everybody room and slow down,” he advised.

“Remember that 15 mph is three times faster than walking. Here’s a comparison: Imagine driving 55- mph versus 150 mph.”

When bikers do head to the trail, they’ll need some off-road skills. Though not a mountain- bike mecca like Durango or Moab, the Santa Monica Mountains offer challenges for any fat- tire fan. “The trails in the Santa Monica Mountains are as diverse as any in the country,” said Langton, “especially the narrow single-tracks, which are dry and rocky. Cyclist often encounter rocks, logs and stream crossings.”

How To Ride Pedaling Uphill

Keep body down close to the bike, bent at waist, butt back, pulling on handlebars toward hips, not chest. Staying seated adds weight over rear wheel and increases traction. Staying seated can be alternated with standing, which uses upper- body strength to pulse rear tire by pulling back and up on handlebar at start of each pedal stroke.

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Cruising Downhill

Keep butt back, out of saddle, with thighs resting against rear part of saddle, waist and arms bent. Keep feet horizontal on pedals. Staying out of seat helps absorb shocks, bumps and ruts.

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Jumping Obstacles

Mountain bikes are generally built to take the abuse of riding over logs,rocks and other obstacles. Clearing obstacles takes a well- built bike, and skill on the part of the rider. The technique for riding over any obstacle involves three components:

1. Ride fast enough to get up onto obstacle.

2. Have enough momentum to get over obstacle.

3. Keep weight evenly distributed for descent, shifting center of gravity to rear of bike.

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Turning

Keep inside leg up and outside leg down, bending body into bike and lowering center of gravity. Lean rather than steer into turn to increase contact of tires with ground. Begin braking before rather than during turn.

Treads for a Reason

Mountain bike tires are knobby for high traction when gripping rough terrain. Treads vary according to riding surface. In general, wider, deeper treads are used for unpaved surfaces. Flatter treads are an option for faster rides with minimal rolling resistance. Serious bikers match tires to riding surface.

A. For hard surfaces.

B. For loose dirt.

C. For climbing and cornering

D. For smooth surfaces.

Gearing Up

Shorts: Cycling shorts are padded for comfort.

Tire Pump

Tool Kit: Spare inner tube, patches and glue, wrenches, chain tool.

First Aid Kit: Sunscreen, insect repellent, bandages, moleskin.

Shoes: Mountain type has more rugged soles.

Drive train / Gears: 15-24 speeds, 3 chain rings in front

Helmet: A must in California for riders 18 and under.

Gloves: Padded to absorb road shock, protect against blisters.

Water bottle

Frame: Chrome/ moly steel, aluminum, carbon fiber or titanium.

Tires / Wheel Rims: Wider with smaller circumference than road bikes.

Bike Price: $250-$1,000 plus.

Off- Road Etiquette

* Be courteous to other trail users. Give advance warning when approaching hikers, horsebackriders and other bikers.

* Obey 15 mph speed limit on all back- country trails in the Santa Monica Mountains.

Off-Road Tips

* Keep weight shifted back.

* Always use both brakes equally. Applying one or both brakes suddenly can cause an “endo” (end over handlebars).

* When riding on gravel, use your body weight to move your bike, rather than the handlebar and front wheel.

* Bend at waist toward bike whenever possible.

* Keep elbows close to body rather than stuck out; this faciliates steering.

* To prevent erosion, avoid skidding, reduce speed in corners during turns and don’t cut switchbacks or bushwhack off- trail.

* Be ready to brake at all times.

* Be alert to changing terrain.

Getting Involved

The Santa Monica Mountains offer a challenging network of trails for mountain bikers. Keep in mind that off- road doesn’t mean off-trail. General rule of thumb for mountain bikes: Most fire roads are open unless posted closed; trails narrower than 6 feet are closed unless posted open.

* CORBA (Concerned Off-Road Bicyclists Assn.) (818) 773-35555 or write P.O. Box 784, Woodland Hills, 91365.

* For trail information: National Park Service, (818) 888-3770; California Department of Parks and Recreation, (818) 880-0350.

Sources: CORBA; Mountain Bike magazine, “Bicycling Magazine’s Mountain Biking Skills”; “Bicycling: Touring and Mountain Bike Basics” by Peter Oliver; “Mountain Bike Magic” by Rob Van der Plas; “The Basic Essentials of Mountainf Biking” by Mike Strassman; REI; Researched by JULIE SHEER / Los Angeles Times