One of the most common failures we see on Polaris vehicles is CVT (Continuously Variable Transmission) drive belt failures. While these failures can be expensive to fix, the majority of them can be easy to prevent.
The easiest way to extend your belt life is to use the low gear drive range when you are not operating the vehicle at high speeds. Heat is one of the belt’s biggest enemies. The clutches on most CVT systems incorporate fan blades into the clutch design, and the faster the clutches spin the more air they circulate through the belt drive housing. By operating the vehicle in low range, not only are you applying less stress to the belt, but you are also moving additional cooling air over the moving parts. That keeps them cooler and helps them to last longer.
Our normal rule of thumb is that low range should be used below 15MPH, but you should check out your owner’s manual for specific guidance on the particular vehicle you own.
The second most common failure that we see is hourglassing of the belt. The term hourglassing comes from the way a belt looks after this failure has occurred. If you turn the belt sideways you can see that it goes from being full width, to being narrow where it is burned, and then back to full width again. The most common cause of hourglassing a belt is when the vehicle gets stuck and the operator applies full throttle to get the vehicle to move. When this happens, the drive clutch will spin at full speed, but as the belt is not moving, the clutch will overheat the belt where it contacts the drive clutch which then hourglasses the belt.
Depending on the degree of hourglassing, the belt and drive system may still be functional after this happens, but the vehicle will exhibit a driveline “knocking” as the hourglassed section of the belt passes over the clutches. The best preventative against hourglassing is to use the low drive range along with the 4×4 drive system when you are operating in areas where you might become stuck. If you do get stuck, and applying throttle is not moving the vehicle, then either use your winch to extract your vehicle or have another vehicle tow you to a point where you are no longer mired in the mud, sand, or water.
While Polaris offers an extended belt warranty on their vehicles, this warranty only applies to failures that result from a manufacturer’s defect in the construction of the drive belt. Upwards of 98% of belt drive failures result from misuse, abuse, and a lack of maintenance, and none of these failures are covered by the drive belt warranty.
There are other causes of drive belt failures such as getting water in the belt drive hours, or not keeping the air filter for the CVT housing clean, but they only make up a small percentage of the drive belt failures that we see.
Below is a drive belt failure analysis poster that Polaris provides to dealerships. This poster displays images and causes of the most common drive belt failures.
While this blog post primarily discusses Polaris vehicles, the concepts apply to ATVs, UTVs, and Side by Sides (that utilize CVT drive systems) from all of the OEMs produced by Yamaha, Kawasaki, Suzuki, Polaris, Honda, and Can-Am.