My toro 3000 60" was in my garage I realized that the rear tire on the discharge side was totally flat. I took it off started to fill it with air then sprayed it down with soapy water to find the hole. I plugged it and then began to fill the tire the inside sidewall of the mower was bubbled out in a couple of spots and once i filled the tire all the way up the left side of the tire was bigger than the right side (misshaped). I know I need a new tire but I was curious as to what could have caused this? I'm sure this wouldn't be under warranty of the mower even tho it's only a year old, due to it being a tire. I didn't hit any big bumps or anything so I have no idea what could have caused this?