Originally posted by robk
A couple of friends of mine clued me in to something about tires: The insert's hardness controls the tires temp. (harder= cooler running tires, softer=hotter running tires) and the airgap controls how quickly they heat up (more airgap = quicker heating up) . This is pretty simplified and does not take into account that softer inserts might help the car make more traction by conforming to the surface etc., but it does give you an idea of how to predict what inserts do.
Thanks robk, that helped lots. I've just started onroad this year and im still learning stuff. Would running a softer insert make them wear out faster? or would that not make a difference