As Dyno stated, what kind of a car and how much it weighs means a lot. A typical sedan in race trim will run aproximately 3500 to 4500 lbs. You DO NOT want to go sidways with a car weighing two tons on two ply tires. What is your investment worth to you? What about the drivers safety. Land Speed Racing is a safe venue...if you use your head. Safety gear (of which I include tires) is the most important thing you will spend your money on. Don't F..k around, buy the best to start with. It makes no sense to buy a SFI 5 or 10 firesuit if you think you might eventually need a 20, and likewise, why not buy the best (hence safest) tires from the get go? I ran the 2 ply tires on my 4300 lb. car with no problem, but that was because of my own ignorance and the fact that I never spun. That brings up another point. No car should be run on the salt without a panhard bar rear suspension. NO chassis manufacturer recomends running a diagonal link on ANY SURFACE other than a drag strip. Heim joints are not made to withstand side stresses such as placed on them by a spin. Building a safe race car does not mean simply bolting on "race car parts". Research what you are using and what it was manufactured to do. Bob