Quote:
Originally Posted by bestclimb
I was hoping you would chime in with some intelligent discussion and information. I am aware that tires don't strictly follow friction theory I'm not really sure why I tapped it, other than contact patch does not directly correlate to traction and there are a several things going on. Perhaps you can correct inform me if my understanding that one of the functions of tire size is temperature control for the contact patch?
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Strictly speaking, the function of tire size is to have adequate load carrying capacity (where inflation pressure is also part of that equation).
And while it is true that the more load on a tire (all other things being equal) results in higher operating temperatures, the rubber compounds in tires are selected to keep the operating temperature from becoming too high, not the other way around. If the goal was to strictly keep tires cool running, the rubber compounds would be different.
A good example of this is winter tires - which have higher operating temperatures (all other things being equal), but because they operate in cooler weather, their operating temperature is within reasonable limits.
Race tires is another good example. The tread rubber compounds are selected for grip - and while heat generation is a minor consideration, the problem is that it is possible to over heat the rubber compound and the grip goes away. So race tires come in a variety of tread compounds with the idea that there is a range of values that are too high for a given compound. Careful selection of the right tread compound for the conditions results in faster laps times.
If you follow Formula 1, you'll know that Pirelli was asked to develop tires where the fall off in grip is pretty dramatic - putting tire strategy into play.
And, yes, there is a lot going on when it comes to tire grip. Getting an 10% increase in the size of the contact patch doesn't result in a 10% increase in grip.