In most of the sport cars I see that they have different wheels for front and rear. Rear ones are usually bigger, but their width ratio is also bigger(they're wider and they're also relatively wider). Often their tread is also a bit different than front ones. I want to know how does this affect friction? What changes does it do to wheel's friction in longitudal, what changes - in lateral direction. Does wider tires mean more longitudal friction and not as much lateral friction? Does it have more friction at all? I'd be happy to find this out. It'd be even better if somebody could give me some pacejka parameter examples for front and rear wheels of the same car.

Thanks!:)

Your googling skills need work: http://www.physlink.com/Education/askexperts/ae200.cfm

This information helps. However, I want to find out now how softness affects friction. How much does it change behavior of friction curve and how much the peak point rises when the softness increases.

The width effects friction as it has more contact to the ground.

The amount of deflation negatively impacts friction as its force becomes evenly distributed.

A wheel rolling creates static friction unless it slides.

The diameter of the wheel doesn't do anything to friction, but it changes how the entire car is affected by air friction

Treads are designed to better grip surfaces of different types

OK! I'm gone sort my questions.

• Does wider tire mean(in most cases) higher friction peak?
• Does wider tire mean(in most cases) more asymptote fall(more friction redux at too high slip angle/slip ratio)?
• Does wider tire mean higher longitudal friction boost and just a little laterial boost?
• Does wider tire mean sharper friction curve?
• How does different types of grip aswell as different surfaces affect the shape of friction curve? It'd be great to have some examples.

Thanks!:)

Maybe somebody has got the required equipment and set of wheels(P225/50 R 18 and P245/45 R 18 wheels or something similar) to test their friction and get curve for me? I would be really thanful as I don't have any of required items and I also got no money(would be strange if I had that much in age of 15). If somebody can get me those curves, I can than finish testing my 1st version of vehicle physics and, hopefully, they'll result in nice, advanced thing:)