The Evolution of the Snowmobile Track

 

Story and Photos | Hal Armstrong

The endless rubber track that puts the “Go to the Snow” and provides flotation on the “white stuff” is what makes a snowmobile unique in the motorsports world.

Think about it for a minute. The sleds of today and yesterday were designed at a CAD station or drafting table with the track as the common starting point. It is the common denominator that all snowmobiles are built around. The first rubber tracks were used for the most part on bogie wheel suspension systems. Track evolution did not occur in isolation. Track suspension design, track drive and placement of engine coolant heat exchangers were all instrumental in the evolution of the track. The endless rubber track created by Bombardier would be a key component in the explosion of the snowmobile in the 60’s with the majority of snowmobiles built using a derivative of this key component. As snowmobile sales continued to explode Goodyear, B.F. Goodrich, Uniroyal, Gates, Dayco and Yokohama entered the track business.

Bombardier 1st Patent

When Carl Eliason, Joseph Bombardier, David Johnson and Edgar Hetteen among others began tinkering with over the snow vehicles over 60 years ago they all had their own ideas on how to provide traction and floatation on snow: chain drive with metal or hard wood bars used from farm conveyors, canvas tracks wrapped around rubber wheels or even small scale caterpillar tracks borrowed from the military.

The breakthrough came in the mid50’s when Germain, the eldest son of J. A. Bombardier, was awarded a patent titled “Endless Tread for Motor Driven Vehicles” in August 1959. This first rubber track had the following features:

It had two longitudinal rows of openings that were spaced to engage into the patented Bombardier rubber coated drive sprockets invented by J. A. Bombardier.

Metal reinforcing rods were molded across the width of the track to provide lateral rigidity and work as traction (lug) device for forward traction.

The track was manufactured on a Bombardier designed vulcanizer that produced a one piece rubber track (no splices)

Snow Goer Canada spoke with the man who many consider the guru of snowmobile tracks, Denis Courtemanche from Camoplast. Denis started with Bombardier in 1962 working in the track division with Germain Bombardier as his first boss. Denis recently retired after a 52year career working with SkiDoo and Camoplast. He was a key person in the development of the “Challenger, Ripsaw and Cobra” tracks to name a few.

SGC: The first rubber tracks in the early 60’s. What were the issues with these first tracks? Denis: Not much changed in the construction and design of the early all rubber tracks from the original design. In those days the track was made with a 3ply cotton fabric to provide a flexible longitudinal reinforcement to prevent the track from stretching while under load. The original reinforcing rods were made of spring steel, which provided the lateral stiffness to the track. The rubber extrusion over the rods formed a natural drive “lug” which was less than ½” in height. These tracks worked well for the low hp sleds of the day but they had two fundamental issues.

First the lack of lateral traction to prevent “fishtailing” on ice or hardpack snow was a problem.

The cotton fabric would shrink during summer storage. With the Bombardier track, the “shrunk track” in combination with the metal rods which are extremely stiff and did not readily flex in response to obstacles encountered by the sled. Since severe shocks are encountered quite frequently during normal snowmobile usage, it is extremely important that the belt be able to withstand such shocks without breaking or bending such rods. The result was a tendency for the metal rods to break, bend, or to tear loose from the surrounding rubber material during use. The metal rods also add considerable undesirable weight to the vehicle SGC: What was the solution to solve this problem? Denis: Back in the early 70’s, an alternative to the rubber track was to mechanically attach transverse metal bars or channels onto a belt surface with rivets to provide the necessary driving traction and maintain track rigidity. This track type had the advantage that if one of the steel cleats broke it could be replaced easily and would not damage the track or snowmobile. Arctic Cat and Polaris used this track type.

The solution for the all rubber track was to use fiberglass stiffeners in place of the steel rods. The design of the rods must provide transverse rigidity as well as the flexibility need in response to shock, so they will flex rather than break. The unidirectional fiberglass also has a very strong memory such that it will always return to the same position it was formed in. These stiffeners are also light in weight, inexpensive to manufacture and easy to incorporate into the belt during the belt forming operation. Once incorporated into the belt, these stiffeners are virtually unbreakable, thus adding considerable life to the snowmobile track. The resin used with the fiberglass determines the strength of the rods. In 1992 with the introduction of the more powerful muscle sleds like the SkiDoo Mach 1 and Polaris Indy 650, we switched to a new proprietary epoxy to improve the flex strength. Today you seldom hear of track rod breakage. SGC: As liquid cooling became more mainstream in the late 70’s80’s and horsepower increased what other challenges were created for track manufacturers? Denis: The original tracks used two ply of cotton fabric. Sometimes we ran three ply to reduce stretch. As speeds increased in between 197580 we switched to nylon cords to reduce stretching. In 1990 we tried Kevlar cords, which was expensive, and while strong in tension in compression the Kevlar cord is week. Polyester cords are used today in various sizes and construction depending on the application. In the construction of the track the cords are located in the center of the track thickness. SGC: Today all the hype is on track lug height and design. In fact the new tracks like the Ripsaw and Cobra have revolutionized track design so much that many riders today do not stud their tracks. Can you take us through the evolution of lug design? Denis: Originally the lug profile was very low because HP was low. In ‘92/’93 we started to increase the height of the profile of lug. Original lugs were ½”3/4” in height. In ‘92, we went to 1”, which was a big change. As Hill Climb Racing out west grew the aftermarket industry had developed plastic paddles to attach to the tracks of the day for better climbing. We were approached by Western Power Sports to build a track made with two inch lugs. We made the track with no warranty and they worked very well. The first year there was only two of these tracks running on the hill climb circuit. In ‘93 we introduced the Challenger track that had a two inch high lug. The following year, 90% of the competitors were running the new Challenger track. We soon started to hear about people wanting to use it on trail sleds.

That really is what kick started the interest in tracks with increased lug height. SGC: The drive pitch is increasing in length with the industry standard now 2.86” or 73 mm. The 2015 SkiDoo Summit 174 has a 3” pitch track. Why the longer pitch? Denis: The original rubber tracks had a drive pitch of two inches. As the industry standardized on the 121” track length for trail sleds, the pitch increased to 2.52” to reduce weight. How is this? A 121” track is the length of the circumference of the track. That works out to 48pitch track. As suspension travel increased, the diameter of the front drive sprocket increased to accommodate a 2.86” drive pitch. That same 121” track is now a 42pitch track. The weight loss equates to four pounds with six less track rods and twelve less steel clips. Reducing rotational weight by four pounds improves acceleration, suspension performance and fuel economy. With the move to three inch pitch tracks in the mountain segment the track weight is further reduced. Will we see three inch drive pitch on trail sleds? Time will tell. SGC: Single ply tracks further reduce weight. What developments prevent these tracks from stretching? Denis: Today’s track use cords that wrap along the length of the track. This limits track stretching which years ago we had to use a fabric in 23 ply’s to prevent stretching. It all added up to increased weight. Today 50% of the tracks made by Camoplast are single ply. They have less rolling resistance, which increases top speed and reduces the power needed to rotate the track. SGC: Where do you see track design going in the future? With 4stroke engines running at lower rpm than a 2stroke the engine noise has dropped to the point where rotational track noise is what the rider and bystander hear most. What work is being done on this issue? Denis: Noise generation by a track is a complicated issue. To further complicate matters we have seen the same track like a Ripsaw create more noise on different suspension types. So the suspension design as well as speed of operation also has a huge impact. Maybe one day we will have a truly silent track design.

The other trend is the increase in track length away from the 121” to the 136”,137”, 144” for cross over sleds. Track lugs are getting higher and track lengths are getting longer. Summary: Snowmobile tracks used in the 70’s and ‘80’s were built by a variety of manufacturers with the sled builders having a huge influence on dimensions and track design. Track design had very little influence with the consumer when making their sled purchase. It was either go with a brand using the rubber track or cleated track. That all changed in the mid80’s with the rubber track becoming the industry standard. As the popularity of mountain riding increased in the mid 90’s, longer track lengths and deeper lug designs spun off to the trail rider. Today the consumer has a variety of track options to choose from to increase performance on the trail or the steep and deep. Racing has improved every aspect of the snowmobiles we ride and todays tracks are no different.

 


This article was originally published in the October 2014 issue of Snow Goer Canada Magazine. Be sure to get all the latest snowmobile news in your hands by subscribing today. If you missed an issue on the stands, or would like a copy of the issue this article was featured in, back issues are also available. Snow Goer Canada Magazine gift subscriptions are also available.

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