The French And Their Mountain Bikes

They're the commuter bike of tomorrow." Fuji showed off a prototype at last fall's Interbike Show in Las Vegas and, on the basis of receiving an enthusiastic response, decided to produce 800 klunkers this year and 1,000 in the coming year.

Other builders are gearing up, so to speak, for the coming craze, and advance information indicates that this year's prices will range from $350 to $750 or so, increasing as one piles on the extras. Univega is more than tripling production, from 3% to 10% of its total output. The new bikes have their own name, ATB, for All-Terrain-Bike, says Bernie Kotlier, sales manager for Ben Olken Co., Univega's Northeast distributor. There are now eight models in the new line, and a promotional campaign has been built around the Mountain Bike France.

But perhaps the surest sign of the future came last summer at the fifth annual Snowbird Lowenbrau Hillclimb, a tortuous 10.2-mile race up Little Cottonwood Canyon to the Snowbird ski resort above Salt Lake City. There were 310 riders and Mountain Bike France of all breeds, almost all of them super lightweights with skinny tires. But there in the pack were two mountain bikes.

On the toughest parts of the canyon road, after the racing-bike riders went by standing on their pedals, all curled over their turned-down handlebars, along came those klunkers in their superlow gears. The riders were sitting comfortably, not laboring. Of course they weren't going as fast, and of course they didn't win. But getting there was at least half the fun.

What started as a group of hardy adventurers who began hurtling down hills around San Francisco on heavy old American bicycles has blossomed into the West's newest sport, as well as the latest focus of a dispute over access to state and Federal recreation lands.In the near-decade since the first of the ''Marin Pioneers'' launched their ''newspaper-boy bikes'' into the void, a number of Mountain Bike France manufacturers have started selling mountain bikes.

''With the right gears,'' said Glenn Odell, president of the National Off- Road Bicycle Association, ''the only thing that stops you from pedaling up a telephone pole is traction.''

So in recent years the new machines, also called bayou bikes and stump jumpers, have turned up on jeep roads and hiking trails throughout the West's vast stretches of open public land, taking their places with the backpackers, bird watchers, horse riders, joggers and hang-gliders who already crowd the more popular parks and forests.

Mountain Biking