From the 1960’s to the mid-eighties what could best be described as “Personal Off Road Vehicles” evolved from six wheels, the JiGer, to three wheels, the Honda ATC90, to the first four wheeler, the Suzuki LT125. By 1985 Honda, Polaris, Suzuki, and Yamaha all had four wheeled ATV’s on the market, but one of these stood out.
Polaris’ 1985 Trail Boss was the company’s first production ATV, and they started out ahead of the pack with a list of innovations, most notably the first fully automatic belt drive transmission eliminating any need for the rider to shift gears. The 250 cc two stroke ATV was also the first four wheeler ATV made in North America, boasting MacPherson Strut front suspension, all wheel disc brakes, and full floorboards over foot pegs, the Trail Boss was a real show stopper.
The Polaris continuously variable transmission (CVT), although new to the off road scene, was simply adopted from the snowmobile industry where it was well proven and established. Some would argue that the CVT is flawed, or that it has no place on an ATV as they favor the direct hook up of a gear transmission, but the convenience and lack of skill required to operate the system won the approval of most riders. In reality most would agree that the CVT is well suited for recreational use, as it does allow the driver to focus on other aspects such as scenery, and terrain. For those in the off road racing scene the manual transmission is still top dog, as specific shifting is required as the rider reads the terrain. There is some debate as to the validity of the CVT in the workplace and agriculture, even with the addition of large bore engines and low gear, nothing pulls like gears. For this reason Honda still is the choice of many contractors, hunters and farmers as they are the only major manufacturer to still offer a full line of geared ATVs.
The CVT isn’t without its faults, as anyone who tries to overload an ATV in high gear will attest to. If there is too much load the belt will slip, heat up, and burn out, not a welcome situation when far from base. Unlike their snowmobile counterparts, ATVs aren’t designed to quickly or easily change the belt. Often multiple plastics and foot wells must be removed prior to accessing the belt, not a trailside repair for most riders.
Belts can also easily get wet, if you are the adventurous type who ends up in deep water. All CVT belt systems are vented to stay cool, but if you go deep enough the water goes in the vent and the wet belt begins to slip. Most manufacturers today offer a belt housing drain plug just for this scenario. Again, problems can and do arise from wet belts turning in to burnt or failed belts while on the trail.
There are solutions for both these issues, firstly, don’t overwork your CVT, use low gear or lighten the load, and the addition of a snorkel kit not only keeps the water out of your engine and exhaust, but the third pipe is to extend the height of your belt vent.
In spite of the CVTs faults, it is still the most popular choice when purchasing an ATV. The convenience and constant power wins out over the seemingly insignificant risks. In my opinion, Polaris took a big step in keeping ATVing fun with the automatic transmission. The ease of use drew the whole family, young and old, back in to the sport, not to mention the vast accessibility this system offered those with lower limb disabilities. The ability to simply “pin” the throttle and hang on was undoubtedly what hooked so many buyers.
All the other manufacturers but Honda eventually followed Polaris with belt drive systems, while Honda developed an electronic shifting system offering full automatic transmission without the use of a belt, and those who have come to depend on the gear transmission will normally buy nothing else.
The CVT is, for the most part, a reliable means to keep constant power and control over your tires, even while you are negotiating a steep hill, or a deep hole. Eliminating the need to shift does offer a level of safety, even for the most experienced rider. The CVT is here to stay as manufactures constantly develop clutch and belt technology, providing a system as reliable as a geared transmission as is possible, a system innovation introduced thirty years ago by Polaris.
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