As soon as I put these tires on, all four leaked air. I took them to the installer and was told it was a problem due to worn tire rims. Skeptical, I replaced one of the rims and the tire still leaked. I had to put air in 2 of the tires every week and the other two monthly. I'm talking down to 15p.s.i. (I've since read many reviews of Cooper tire owners who had the same problem). About two months ago, I replaced the tires with Continental True Contact tires and they have not lost a single pound of pressure in ANY of the tires since I put them on. Also, these tires do NOT slip in the rain like my Coopers did. I'm betting they do much better in the snow too. I'll never buy Cooper tires again.