The old-fashioned sled is getting a radical redesign for Christmas.

Manufacturers are rolling out newfangled models with upscale price tags, hoping to do for sleds what Rollerblades have done for roller skates. But in a business dominated by cheap, plastic coasters _ most costing less than $15 _ they face an uphill battle.

After a heavy snow in Boulder, Colo., recently, two dozen sledders zoomed down a park slope on inner tubes, saucers and thin plastic sliders. ``The cheap plastic stuff is the most fun,'' said Dan Chomyn as his five-year-old daughter, astride a $5 Barbie saucer, yelled for a push.

Makers of the new sleds hope to leap that hurdle by pushing their offerings as a special treat to go under the tree rather than an impulse purchase made when snow starts to fall. People will spend more for sleds when they're buying them as Christmas gifts, says Donna Ayoub, the product manager for Rubbermaid Inc.'s new sled line.

Rubbermaid has designed a line of sleek, sturdy, hot-purple molded-plastic sleds that retail for $30 at mass marketers like Toys ``R'' Us and Wal-Mart. The sleds allow the plastics giant to put its ice-chest assembly lines to use off season. Former Canadian Olympic-luge racer Bruce Smith created a molded plastic luge sled for Quality Dino Entertainment Ltd. of Winnipeg, Canada, that sells for $50 to $80. And tiny SnowBlade Corp. of Franklin Lakes, N.J., introduced a single-runner sled for $40 that looks like a giant ice skate with a seat.

``When kids see something is new, cool and fun, they jump on it ferociously,'' says an optimistic Jim Farrin, president of SnowBlade. Mr. Farrin says his company's design was based on ``jack-jumpers,'' wooden skis with seats that loggers used in the New England woods. The target is children between six and 16 years old.

``People will spend $400 on a snowboard,'' says Greg Johnson, president of Quality Dino. ``What's $79.95 for a funner, faster, alternative sled?''

If the gamble works, sled makers will be reversing a decades-long slide in sales of upscale models. Over the past 30 years, the traditional wooden sled with steel runners has all but disappeared. Flexible Flyer still makes the old favorites, but in the 1980s, facing plummeting sales, it cut costs by using thinner, less-costly woods and jumped into cheap plastic models to increase business. It had all but given up on upscale sleds when Roadmaster Industries Inc. of Atlanta, a maker of bicycles and other recreational toys, acquired it in 1993.

``The first thing we did was put more wood and more varnish on the sleds,'' says Jeff Hinton, Roadmaster's chief financial officer. By making it ``the way it used to be made'' and putting more marketing muscle behind it, the company doubled volume in 1994 to about 150,000 sleds, he says. Still, Mr. Hinton says, ``we sell five times more of the cheap stuff than the classic sleds.''

This year, the company has added to its fleet a new steel-and-tarpaulin sled with polyethylene runners that looks like a miniature catamaran. At $80 to $100, the Sno-Kat costs twice as much as Flexible Flyer's century-old Classic Racer. ``Any growth is going to be driven by new products,'' Mr. Hinton says.

Unlike most inexpensive sliders, the newfangled sleds can usually be steered, giving riders more control. Because of that, Mr. Smith contends that his highspeed luge is safer than what most kids ride today, though he still recommends that riders wear helmets. His design owes its origin to the Canadian Luge Association, which four years ago tried to develop a simple, children's version of the fearsomely fast Olympic sled. ``If you want a 28-year-old gold medalist, you start with an eight-year-old kid,'' Mr. Smith explains.

The association soon gave the job to Mr. Smith, who finished 11th at the 1980 Winter Olympics, racing on a luge sled that he built himself. He vastly simplified the design, replacing metal runners meant to rocket down icy tracks with broader plastic versions that can be used on snowy slopes. After selling out all 15,000 luges in Canada last year, Quality Dino expanded production sharply, exporting 45,000 units to the U.S. for Christmas.

But the new sled makers may want to keep in mind the trip another upscale sled manufacturer took down this slippery slope. Hamson Products Inc., of Merrimack, N.H., launched its Scoot-N-Ski _ which looks like a short, fat ski with a scooter handle _ two years ago in New England for $50. But shoppers wouldn't pay that much. Now, the company has slashed production costs and profit margins and is rolling out the snow scooter nationally with a suggested retail price of just $20. ``At $20, it can still be an impulse buy,'' says Len Hammond, company president.