Tires are actually part of the suspension, an 8 ply rating will give a harsher ride over a 6 ply. As far as wear goes that depends on the compound of the rubber, softer compounds give better traction but wear faster than a harder compound. Tire pressure plays probably the biggest role in a failure, air pressure changes roughly 1.5 psi per 10*F, low pressure on landing can allow the tire to rotate (slip) on the wheel at touch down which generally rips the valve stem from the tube, the harder the landing the more likely the tire will slip on the wheel. Here's the scenario, you take off with 25psi in a main on a 95*F day, at altitude the air temp in the tire drops to 50*F, rubber is a good insulator so the air temp in the tire only gets to 65* before landing, now your landing with less than 20psi in that tire, the tire spins on the wheel tearing the valve stem and then the fun begins......