Rbrow53 I noticed it is a tiny bit firmer over bumps but not much. Our temperatures swing so much here, sometimes 40 to 60 degrees in one day, that I decided to carry a little extra to compensate for thoseoccassional very cold mornings when the tires might actually be underflated. For every 10 degrees of temperature loss, you will loose 1 pound of pressure from your tires, so I could have 4 to 6 pounds of tire pressure change in just one
day account of the weather.

 

I bought my son a 2001 police Impals last year with 40,000 miles on it . I had to replace the tires when I bought it and the tire dealer toldus he recommends 35 psi for all passenger vehicles. He's been using that and had no problems.