Story | Hal Armstrong

The history of Arctic Cat is littered with production and race sleds that incorporated new thinking to make better riding and better handling snowmobiles. It all started with the .rst slide rail suspension in the mid 60’s. Track suspension evolution con­tinued through the mid 70’s with lightweight aluminum construction and adjustable front torque arms to improve weight transfer. Ski suspen­sion was also under scrutiny with various leaf spring ski designs and canted steering to allow the skis to tilt into the corner. 

While Cat was acknowledged as the suspension leader in those days, a new independent front suspension had snuck under the radar at Thief River Falls. Complacency perhaps? The wakeup call would happen in mid December 1976 at Ironwood, Michigan. 

Arctic Cat had just come off a dominating season in ‘76 winning the SnoPro title with race sleds, which many consider to be the ultimate leaf spring race chassis. That winter Team Arctic and the rest of the big four race teams had come up against Gordon Rudolph and his IFS sleds. The Villeneuve Brothers had built new Skiroule racers that were fast around a corner but still fragile and hard to handle. Polaris had taken notice and were busy building new IFS and leaf spring chassis for the ‘77 season. Ski-Doo had also taken notice and had built race sleds with IFS. 

The Polaris juggernaut for the ‘77 season started that weekend in Ironwood and Arctic went home with their new race sleds that were now obsolete. Roger Skime and company went into damage control over Christmas and would have their first IFS sled on the racetrack at Hartford, Michigan in early 1977. It had taken Durmont Wahl and Dennis Zulawski less than a month to design and fabri­cate the 77-1/2 SnoPro racers. It would be a quick education into the world of bump steer, caster and camber angles and spring preload. Life was so much sim­pler with leaf springs. 

While Cat was taking their lickings on the racetrack, Roger Skime reassigned a young engineer (Roger Gage) from Advanced R & D to the race department to design a new race chassis for the 1978 season.

The Z-Bar Front Suspension 

Roger Gage had seen how touchy the steering setup was on the 77-1/2 racers as the suspension moved through its travel. Arctic had set the following criteria for the new front end: 

• Ski Travel: 5” 

• Eliminate bump steer to prevent skis from toeing in and out 

• Keep weight to a minimum load. This design is better at holding the track .at on the ground for more traction under cornering. 

The increased adjustability with the twin shocks pro­vided more flexibility with setup. For example if the sled was pushing going into the corner, the left side shock spring tension could be increased to put more load on the inside rail in combination with increased front ski pres­sure. The front and rear suspensions now were more connected than ever before in terms of improving corner­ing speeds. External shocks also reduce unsprung weight to improve response time of the suspension.

Style and Power 

The ‘78 SnoPro Cat was unusual looking to say the least. The styling of the sled was designed by Leon Raiter who designed many of the classic Cat’s. The boxy styling was functional and was given the nickname the “ Mail Box”. Distinguishing features included the radiator location and the squared off air dam. The front air dam is reminiscent of Can-Am race cars of the day that were using ground ef­fects for improved traction. The completely enclosed hood design protected the twin expansion chambers from snow and ice and kept the pipes warm to improve per­formance. Expansion chamber design was rapidly developing at the time. 

Arctic was now using Suzuki motors in three engine options (250, 340, 440) to compete in all three Pro classes. Arctic clutching was used initially with the switch made to Comet primary clutches later in the season. 

Roger Gage had set out to design a lightweight race sled and the machine tipped the scales at just 325 lbs without using any exotic alloys. Mission accomplished! 

Did it deliver? 

Team Arctic started the season with three drivers. Legendary Larry Coltom, Bob Elsner and rookie Jim Dim-merman. Larry had a bad crash after the second race and hung up his leathers which, according to Jim Dimmer-man, turned out to be a bonus for the team. “Larry Coltom is a whiz with clutching and he worked as a development rider while we were away. Larry also came up with the idea of slide rail lubricators.” Jim Dimmer-man recalls. “IFS required more track pressure on the front of the slide rails. The hyfax were heating up, slowing the sled down especially on the ice tracks, which were be­coming more popular. Arctic was the first to install a slide rail lubricant tank on the rear of the sled to pump lubri­cant onto the sliders. This made a huge difference in top speed and was an innovation still used today. 

The clutching and setups Larry developed that winter were quickly brought to the race sleds and by the mid point of the season we started beating Polaris at its own game. Bob Elsner would end the ‘78 season as the high point driver.” 

The Z-Bar chassis would be the platform used by Arctic and Scorpion till Arctic Cat went out of business at the end of the 1981 season. Bob Elsner won the World Championship in 1979 and Brad Hulings on a Scorpion in 1981. Jim Dimmerman would race his Phantom race sled with the Z-bar chassis and beat the Ski-Doo Twin Trackers in 1984 at Eagle River claiming its third World Championship. 

Innovation Continues 

The 1978 SnoPro Cat ushered in Arctic Cats continuous improvements of front and rear suspension designs. The Z-bar never made its way to a production sled but the A-Arm suspension pioneered by Arctic in the mid 80’s addressed many of the shortcomings of a trailing arm suspension. The outboard mounted shocks for a track suspension were used in production applications in the mid 80’s and was picked up by some of the competition for production sled applications also as long travel suspension design hit high gear in the late 80’s. Arctic Cat learned a lesson the hard way back in 1977. Never stop innovating! 

 


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