Gone are the dual downhill and speed events for mountain bikers. Replacing them at the 1999 Winter X Games is a competition sure to be full of surprises for world-class riders who've done just about everything else on a bike.

"I think it's going to be cool. It's going to to be exciting," Mercedes Gonzalez-Natvig said Tuesday after the first practice session for Biker X. "It's definitely going to give the spectators something to really watch out for. It's going to be great for TV. For us, it's something relatively new, but I think most of the athletes are looking at it as a challenge. It's something new, it's exciting."

What makes Biker X unique is it's relatively simple format: Six riders will exit the starting gate simultaneously in a mass scramble to be the first one down the course.

As in past Winter X dual slalom competitions, riders advance through a series of preliminary heats, culminating with six-rider finals for the men's and women's gold medals. But unlike the duals of years past, all six riders will be looking for similar lines down a course of bumps, berms and gaps. And that's when it'll get interesting.

"You have to get out of the gate first, and then try to stay out there and block," said Shaums March, who helped design the Biker X course but won't compete because of a nagging rib injury. "And just stay conservative, because everyone is out there watching you, waiting for you to make a mistake.

"Definitely with six people on the course you'll need a strategy. Really the smoothest guy out there will win. (But) there will be a whole bunch of mayhem. There is just going to be a lot of carnage, too. Hopefully nobody will end up going to the hospital."

Adding to the difficulty is the fact the mountain bikers are sharing the course with Skier X, which is considered the most extreme of the events at Winter X. The terrain and setup is one of the most aggressive the mountain bikers will face all year. Then there is the snow.

On the World Cup circuit, these riders encounter their share of elements. Rain or shine, on dry mountain sides, over clay, sand, tree roots and rocks, they are used to adapting to whatever elements get in their way.

But the snow was the talk of Tuesday's practice session. If these riders had their way, they'd rather ride on ice then the soft snowpack they'll encounter during qualifying and competition. The bikes have special studs on the tires for traction. But with the course getting a fresh covering of snow Tuesday and again Wednesday, the studs aren't as effective.

"Snow is quite different than anything we race or practice on all year," Gonzalez-Natvig said. "It definitely took me three or four runs to get comfortable. I finally did a couple of the jumps on my last run, so that's encouraging. But once you do one jump, it gives your body and bike a whole new flow.

"It's much harder for us to adapt to the snow, because it's not something we are comfortable with and used to."

With the elbows and handlebars of five other riders competing for space on the course, finding a comfort zone won't be easy.