Spare tires are scary. A couple of weeks ago I was driving to GI to suprise my mother on her birthday. My car started to vibrate. I got off the interstate to get on a slower moving highway. I inspected my tires. No damage visible. I kept driving, the vibration continued and worsened. BLAMMO!!! Blow-out. Stranded nine miles from GI. Happy Birthday, mom. I'm buying you four new tires for my car. Moral of the story. Don't drive for two months on a spare, even if it is a full-size tire.