I have a Jimna 284 that I purchased new about a year and a half ago. I had the dealer put wider tires on the front and rear to help with stability. I recently had the left front wheel suddely fall off after a cruching noise. Turns out what the parts list calls the "Driving Shaft" broke. This is basically a plate with a splined shaft that couples the wheel hub to the turning gears. I just finishing replacing the left front today and was using the tractor, picking up full buckets of sand, when bang, the other side broke in exactly the same fashion. Has anyone had similar experiences? Does anyone think the wider and much heavier tires and rims may be the problem? I'd sure like to figure out why these keep breaking before I go broke. Thanks