Snowmobiles are vehicles designed primarily to move or travel over snow covered terrain. Generally, snowmobiles are open air vehicles with a motorcycle style seat that can accommodate up to four people. Snowmobiles are usually powered by an internal combustion engine that drives a long continuous or endless track which is located in a rearward position of the snowmobile, and substantially below or underneath the seat. This continuous or endless track, powered by the snowmobile's motor, is configured to engage the snow covered terrain and propel the snowmobile over the snow. The track provides a similar function for the snowmobile as a tire does on a road vehicle.
Snowmobiles are typically further equipped with a pair of skis positioned in a forward position. The function of the skis is to provide a front ground contact for stabilization, as well as to facilitate guiding or steering of the snowmobile. A pair of handlebars, accessible by an occupant on the seat, can be pivoted in order to turn the skis and thus turn or steer the snowmobile.
The front skis on a snowmobile, however, have several disadvantages that affect snowmobile performance and operation. For example, since the skis are designed to slide over the snow, they provide very little traction to the snowmobile. Consequently, the rear track often partially overpowers the traction of the ski and continues to push the snowmobile forward instead of through a turn. This partial overpowering of the ski traction causes the vehicle to make a wider turn, thereby affecting the cornering ability and overall handling of the snowmobile. Sometimes the rear track completely overpowers the skis and moves the snowmobile in a forward direction regardless of the direction the skis are turned. This is particularly the case when trying to traverse across hard surfaces such as hard pack snow, asphalt, or the like. The problem is compounded as snow provides a poor traction surface, and in the case of unpacked snow, is easily pushed or displaced. As such, when turning or moving sideways along a hill, the rider must often lean dramatically on the snowmobile in order to weight the front end and get the skis to bite into the snow. To account for these problems, those skilled in the art have equipped snowmobile skis with rails that extend down from the underside or contact portion of the skis. Although the rails are designed to increase the traction of the snowmobile by digging into the snow, these rails result in only marginal improvements.
Another disadvantage of the front skis is that they provide no assistance to the snowmobile's ability to accelerate, slow down, or reverse. In other words, they are passive and provide no driving force. In fact, since all the skis do is slide on or across the snow, they actually decrease the efficiency of the snowmobile as they tend to produce drag and a resistance that the rear endless track must overcome. Moreover, since the rear endless track of typical snowmobiles can sometimes become bogged down by snow, ice, rocks, and other debris becoming lodged in the track tunnel between the track and the seat, the additional resistance of the skis can stop the snowmobile from moving at all.
Still another disadvantage of the front skis is that they tend to ride on the top or upper surface of the snow, whereas the rear track tends to dig into the snow due to its driving force as powered by the snowmobile's motor, thus actively displacing the snow. The result of this is that the snowmobile has a tendency to move or travel with its longitudinal axis oriented on an incline with respect to the ground level, with the front end higher than the back end. In this position, there is less weight being placed on the skis, and thus the snowmobile is more difficult to maneuver and turn. In addition, this can provide vision problems as the rider's line of sight to the ground surface is obstructed causing him/her to have to look a greater distance past the front of the snowmobile to see the ground surface. This problem is made worse at night time since it causes the headlight of the snowmobile to point uselessly toward the sky instead of on the ground in front of the moving machine.