What is the difference between the various types of racing slicks?

[Ghoste]

What determines a drag slick from a dirt track slick or oval track or Formula One? I'm guessing sidewall flex for sure and maybe tire compound but is there more?

[Cooter]

Ghoste, You pretty much got the major differences....If you've ever tried to get a Circle track slick to hook on a Drag Car, you would see how the "Wrinkle" wall and the sidewall on a circle track tire differs greatly.....

[Ghoste]

And that part I knew I guess.  So there aren't any other differences really?  If not, why the different types for the various forms of paved track road racing?

[HPP]

Well, you have bias and radial construction. You have 2,3,4 or more ply sidewalls along with multi-ply tread face variations. Carcass construction would vary based on weight and speed requirements of the differing organizations. An Indy car weighs less than a Cup car which weighs less than a Bonneville car and the resulting weights, speeds, and generated downforce will dictate differing carcass designs. There are differing rubber compounds from hard to soft. There is differing camber patterns built in to some tire treads. You also have the slick vs treaded face as well.

[Ghoste]

I'm just talking about slicks in this case.

[HPP]

I was talking racing tires in general, but take the tread options out from dirt tracks and F1 and the rest still stands.

[Ghoste]

What circumstances dictate the need for bias ply or radials in racing tires?

[HPP]

Track rules or driver's preference, or experience, primarily. There are still quite a few bias ply oval track, road race, and drag tires out there. In my experience, bias plys tend to be a more forgiving design that loose traction in a very linear and predictable manner. Compared to a radial slick which can be pushed to the edge with little feedback until it completely looses grip. At that point it is like driving on ice and will tend to require a significant reduction in wheel speed to regain traction, unlike a bias play that tends to gradually lose and regain traction.

[Ghoste]

Makes sense, I've noticed the same thing in street tires.