I inherited a neglected Polaris 280 with my current house about a year ago. After spending the summer replacing various parts, I've finally got it basically running correctly - with one exception. On the side with the two large wheels and small wheel in the center, the metal drive gear is constantly eating the teeth on the inside edge of the front wheel. This does not happen on the other side (the "one wheel" side) even though there a similar metal gear meshing with the teeth on the inside of that wheel.
I've replaced the bearings and all the wheels, and replaced the wheel with the issue 3 times. For about a week it works fine, then it starts turning circles. Sure enough, the teeth on that one wheel are worn down. Only fix I've found is to replace the wheel again.
Any idea what's causing this?