Originally Posted by Kevin K

Steve I don’t think this is 100% accurate....a thicker insert will make the tire run hotter and cause the tires to build heat and then possibly get too hot and over heat. A thinner insert with the same stiffness will keep the same tire cooler. When you are dealing with rubber tires you also have to think about how that insert is going to heat up during that run not just the tire. Thicker and harder inserts hold more heat inside them then thinner and softer inserts. For what HVAC is asking a thinner insert or just a softer one of the same thickness might help….or even just a change to the front shocks like lighter spring with heavier oil would help...less castor too. When you have too much traction and are traction rolling going stiffer on anything suspension or tire wise isn’t really the answer. If he were to build his tires with thicker insert then the car might not flip over as soon into the run but once the temp comes up they will be uncontrollable. Think about inserts like tire pressure on a real car they build pressure when you run them and they heat up and if you start with too much pressure you end up with a funky tire that wears all weird and gets too hot and degrades.