I've noticed when autocrossing that true race tires have little or no tread (e.g., hoosiers). I've also noticed that some of the serious autocrossers running street tires have the tread "shaved" for better traction. Apparently tirerack will do this for you, for instance.

But now I'm confused. Does this mean that my advans will grip BETTER the more tread I lose?!? That seems too good to be true, but if I understand what the autocrossers are doing, that seems to be the implication (at least in dry conditions...in wet conditions, of course, no tread would be a disaster). I'm used to thinking that as I lose tread I lose traction...do I have it backwards?

Can anyone who knows their stuff clarify this? Thanx.

 

Generally, as your tyres wear, you will lose traction. Now, obviously the more rubber you have on the road the better the traction, so a bald tyre would seem to be perfect. The problem is that the integrity of the rubber is compromised because of all the heat cycles they have been through and the rubber will become hard. Any tyre that has a tread will have some sort of lateral movement depending on the depth also, so shaving reduces the amont of tyre that can move from side to side.

 

Have you ever noticed that when you have run the car hard for a while the tires heated/a little more sticky. Well that is the "wear" rubber on top of the core build. When you lose all of that all you have left is the hard core which is like running with a set of $100 tires from pep boys...

bryan

 

Excellent responses, guys... I get it now. Thanks!

 

i belive u can get a tire shaved because a longer or thicker tread will allow some sideways movement while cornering. the tread will stick to the road but the rest of the tire will be shifted to the outside. like UFO said, this is what u call lateral movement..