My original 1970 GTX came with F-60X15 tires. They were helpless in the rain. Anything over 50 MPH in the rain and you were taking your life in your hands. They were a great improvement over what they replaced for dry road traction. I personally had two that blew out the sidewalls. The first time that happened was as I was returning from the second year race at Talledega. The very inner ply was all that remained and the tire stayed up but what a scary ride.