Another thing to keep in mind with regards to tire pressures and inflation pressure is road conditions. If you hit a pothole with your tires inflated to 32psi, they will flex plenty and deform with probably a bit of a pressure spike from hitting the pothole and suddenly compressing the tire far above what it would normally be. If you had the tires at 55psi, the spike in pressure would be far higher; possibly well above 100psi or so. I know I've had friends who blew out tires from hitting potholes and it blew it from pressure alone - no wheel damage.