With snowmobiles now available with tracks up to 174 inches long featuring 3-inch lugs, custom-tailored ergonomics made for off-trail riding and other task-specific features, it’s hard to believe that, just 21 model years ago, the first “modern” mountain sled made its debut. That sled was the 1994 Ski-Doo Summit. With its low handlebars, track with .912-inch lugs and 108 horsepower engine, it hardly holds a candle to modern mountain sleds. But it started all four manufacturers in a direction that led to today’s ultimate mountain muscle.
Bombardier Births A Benchmark
Despite modern perception, the first purpose built mountain sled was Floyd Brueshoff’s 1971 Shark. A conventional design with an 18-inch wide track, low center of gravity and high power-to-weight ratio, the aesthetically-challenged Shark was built in the Denver area for just one season.
More than two decades slid by before the next truly mountain-specific model appeared, but that next effort would be so successful that it would create a whole new class of snowmobiles. So while most of our Timeline articles focus on older machines, the 20th anniversary of this benchmark snowmobile was important enough to deserve special attention.
High Ideas From Valcourt
Manufacturers had been thinking about better performance in soft, deep snow for some time. Extended track versions of standard trail sleds like the Polaris Snow King Special (SKS) series and Arctic’s Mountain Cats appeared near the end of the 1980s. Ski-Doo had the least success in the steep and deep because its Formula XTC long tracks were just too heavy and clumsy.
Then in the spring of 1993, Bombardier introduced the nearly all-new 1994 Summit. It changed everything about deep snow sleds because it took a comprehensive approach to the special needs of mountain riders.
Built on the new lighter Formula 2000 (or F-body) chassis, the Summit broke new ground for Bombardier. A sprint car ski suspension similar to the Indy replaced the over-engineered and under-performing PRS ski suspension of the XTCs. However, the Summit front end was 4 inches narrower than other F-body models. With the spindles tucked in behind the sloped belly pan, it had less drag in deep snow than other leading arm suspensions including Ski-Doo’s wider trail sled version, so it handled better for side hilling and other off-trail situations.
Plastic skis with metal bridgework reduced weight, added flotation and provided improved performance on sticky snow compared to the narrow steel skis of the XTCs. And a real front bumper allowed better grip and vastly improved leverage for lifting the front end of the sled.
Power came from Rotax water burners, either 583 or 470, with the unique and patented Rotax High Altitude Compensator (HAC) system that ended the need for constant re-jetting in the mountain environment where every additional thousand feet of altitude above 3,000 feet robs another 3 percent of engine power – if the owner keeps the sled perfectly jetted. Miss on the jetting, and the power falls off dramatically.
Adapted from proven Rotax ultra-light aircraft engines and extensively tested on Ski-Doo rental fleets in West Yellowstone prior to full release, HAC automatically adjusted fuel flow as conditions changed. Mounted on the air box, it required no external power so was immune to electrical and computer issues. It weighed next to nothing and cost very little, too. Sensing atmospheric pressure through a barometer attached to a diaphragm that was connected to a double-tapered needle, it automatically adjusted carburetor float bowl pressure as the altitude and temperature changed the density of the ambient air. High altitude clutching and gearing settings were also included.
A15- by 136-inch Camoplast full block track featured a .912-inch lug height. Wimpy by today’s standards, it was the tallest lug then in production (hard to believe, isn’t it?). And it met the snow at a shallower angle than the tracks in other F-body models to further improve flotation.
A tall windshield actually protected the rider from billowing powder snow, and the whole package was finished off with altitude-oriented graphics that left no doubt about the intended use for this new model.
On October 14, 1993, a Summit received the honor of being the 2 millionth snowmobile produced by Bombardier. There were press releases, product photos with company leaders and lots of fanfare for this major milestone unachieved by any other company in the business.
The Summit was very well received by the snowmobiling press. One western publication named it Sled of the Year, and many others across the country acknowledged it as a significant development. Snow Goer named it to the Top Ten list, saying “The Summit makes our list because it’s revolutionary, lightweight, state-of-the-art, and just an all-around darn good sled.”
Long Track Legacy
The Summit started a whole new class of sleds as competitors rushed to create their own version of this high altitude special. Characterized by a deep-lug extended track, single seat, narrow front end without a sway bar, engine and power train optimized for high altitude riding, and a few other evolved features, these mountain specials quickly became a permanent part of every manufacturer’s lineup. They remain with us today as some of the industry’s best sellers. And it was the Ski-Doo Summit that really started it all back 20 years ago.
1994 Ski-Doo Summit 583
Manufacturer: Bombardier Ltd., Valcourt, Québec
Engine: 580.7ccRotax liquid-cooled, rotary-valve, variable exhaust (RAVE) twin with two Mikuni VM-38 slide-valve carbs with High Altitude Compensator (HAC)
Ignition: Nippondenso capacitor discharge (CD)
Power Output: 108 hp @ 8,200 RPM
Clutches: Bombardier Total Range Adjustable Clutch (TRAC) with cam-action driven
Type: Riveted aluminum and steel, polyethylene bellypan, extruded aluminum front bumper,
painted tube steel rear bumper, and Reinforced Reaction Injection Molded (RRIM) Metton hood
Dry Weight (claimed): 483 pounds
Front Suspension: Direct Shock Action (DSA) trailing arm with coil springs over gas shocks
Rear Suspension: Improved C-7 progressive rate aluminum slide rails with 6 rail wheels and
5-position adjustable outboard coil springs over high-pressure gas shocks
Ski Stance: 36 inches
Track: 15- by 136- by .912-inch polyester-reinforced “full block” molded rubber
Brake: Self-adjusting mechanical disc with parking brake