As the 1985 snowmobile pre-season got underway in spring 84, whispers from my contacts at big yellow indicated that they had something special coming later on. And sure enough, in the fall Bombardier announced a new model aimed at performance-oriented trail riders who wanted the ultimate in comfort and ride quality.
The “White Sled” as it was known in Ski-Doo-speak turned out to essentially be a 1985 Formula SS with a plush-riding long-travel rear suspension. And because it followed the introduction of Arctic Cat’s 1985 Pantera by several months, the new Ski-doo Formula SP became the industry’s very last leaf spring performance sled.
The leaf spring ski suspension had ruled snowmobiling for well over two decades. However, by the mid-1980s, it was obvious that the coil-over-shock front end was the future of the sport. Each of the four remaining snowmobile manufacturers had its own version of a coil-over ski out on the trails, but Bombardier continued cranking out less expensive leaf spring sleds for use on all those wide, smooth trails in Quebec.
The “White Sled” had its origin in the 1984 SS-25, a sleek, new, low-profile performance sled for Ski-Doo’s 25th anniversary season that was slotted below the Blizzard 9700 lake racer. In 1985, the SS-25 returned pretty much unchanged as the Formula SS. Essentially a Safari with Bombardier’s low-end, liquid-cooled engine, the SS was a good-looking and very solid trail sled that ran pretty well. It was positioned at the low-end of the new 1985 Formula performance sled family that was otherwise equipped with Ski-doo’s ingenious Progressive Reaction Suspension (PRS) coil-over-shock set up in the front.
The new 1985½ Formula SP slid right in between the leaf spring Formula SS and the coil spring Formula MX. This mid-season entry utilized a skid frame with external coil-over-shock springing similar to that on the discontinued Blizzard 5500 MX, although it failed to match the 10-inch travel of the Blizzard MX. But the new suspension did increase total slide rail travel from 6 inches on the SS to a solid 8 inches on the SP, a big improvement in those days. Track width was also increased from 15 to 16.5 inches for more stability and better deep snow performance. Color was the only other significant change.
The plush-riding SP outsold the SS in 1985, so it was retained in the lineup for 1986 while the SS was discontinued. The only changes on the 1986 SP were revised shock damping, a new voltage regulator, a slightly taller windshield and different trim graphics.
When Snow Week test team tested the 1986 Formula SP, the ride quality made a big impression. “Maximum bump absorption with a minimum of trade off in the handling area,” was their key comment. “On the trail, the leaf spring front end seems to be a perfect match-up for the compliant track suspension as the SP has easy steering and the kind of predictable handling that assures rider comfort and confidence.”
The review also noted that the engine got good fuel mileage on regular or unleaded gas, and that the sled was good in deep snow due to the leaf springs and wider track. The reviewers concluded that, at $500 and a few horsepower less than the Formula MX, the Formula SP was a good lower-cost, high-performance machine.
Having spent an afternoon pounding an SP over some badly beaten Adirondack trails, I absolutely concur with the Snow Week testers. The externally-sprung skid frame did a great job of absorbing the bumps. It was easy to bounce the front end into the air and ride it on the rear suspension a good deal of the time. In fact, I rate it as the best riding leaf spring sled I’ve ever been on, and I’ve tried a whole lot of them.
The Formula SP was a lot of fun, too, with decent ergonomics overall, more than adequate power for trail use and no handling issues. It was also fairly well equipped for the day. My only real complaint was the lack of a front bumper that would have made it a lot easier to pick up and tie down.
Short Life Span
Unfortunately the increasing popularity of coil-over-shock front ends meant that there just wasn’t much of a market left for leaf spring performance sleds. Almost all go-fast buyers were willing to pony up the extra bucks for the improved ride and handling of the coil-over models, so the short-lived Formula SP disappeared after the 1986 model year.
Nevertheless, this relatively rare machine retains the distinction of being the last leaf spring performance machine to make it to marketplace, and that makes it a very collectable snowmobile.
Ski-Doo Formula SP
Manufacturer: Bombardier Ltd., Valcourt, Québec
Engine: 463cc Rotax Type 462 rotary-valve liquid-cooled twin
Carburetion: One Mikuni VM-34 slide-valve float type
Compression Ratio: 6.7 to 1
Ignition: Capacitor discharge (CD)
Lubrication: Oil injection
Power Output: 56 HP @ 6,750 RPM
Electrical Output: 160 watts
Exhaust: Single pipe into free flow calibrated muffler
Drive Clutch: Bombardier “Instant Torque” three-roller square shaft
Driven Clutch: Bombardier cam action
Type: Painted aluminum and steel, painted tube steel rear bumper, Reaction Injection Molded
(RIM) urethane belly pan, fiberglass hood
Dry Weight (claimed): 434 pounds
Front Suspension: Mono-leaf springs with hydraulic shock absorbers
Ski Stance: 32.25-inches
Rear Suspension: Torque Reaction aluminum slide rails with outboard coil-over, dual-rate
Track: 16.5- by 114-inch fiberglass-reinforced molded rubber
Brake: Self-adjusting mechanical disc
Fuel Capacity: 8.4 gallons
Standard Equipment: Speedometer/odometer, tachometer, temperature gauge, fuel gauge, oil level indicator, high beam indicator, kill switch, handlebar pad