These diametrically opposed view points are both valid, but come from two different perspectives. Drag racing vs Road racing. We're arguing apples and oranges.

 

Keep in mind you're talking to a chassis integration engineer for a major OEM as I've mentioned in many posts.

We we have many reasons for putting wide tires on sports cars. Some of that is for laterial grip purposes, some is because we're forced into an envelope of 19, 20, 21 inch wheels that limit the amount of sidewall we can add, some of that is looks. Generally we combat wheel spin with mechanically added grip and stickier compounds because a taller tire isn't the popular choice in other areas. But keep in mind we build the car to handle stock power levels, and not more than that; which is where these issues usually arise.

 

This thread was focused on wheel spin, which is why I brought up this point. But you're correct in the statement that they are two different animals. A taller tire has many poor effects when rounding a corner. The muscle car era is a perfect example of that.

 

Thanks. I think I understand the majority of the forces in play and issues involved and again, while I realize that a taller tire with the same contact patch has better longitudinal vs. lateral traction/grip than a shorter, wider tire (and that lateral grip is opposite), I guess I remain unconvinced that a 305mm wide tire on an F type absolutely has the same or less grip than a 295mm tire with 3psi more (or whatever the numbers have to be to get the optimal contact patch).

Cheers,
Dave

 

That logic would depend completely on what PSI the tires were set to. However, assuming the 295s are at OEM spec and the 305s are 3psi below that, yes they will perform better because you've now created a larger contact patch all the way around. That being said you could just decrease the 295s 3psi and then they would be better. Since you still have to support the same load, you need the same pressure in the tires to hold up that load, and thus contact patch size is the same.

 

R888's

 

Breaking the tires loose on command is why I love my 2015 F Type R.

 

if i could upload a youtube video on here...that would be great ...

 

Don't understand why some say you can't put the power down. Car & Driver got the 2015 R to 60mph in 3.5 seconds. A professional driver, but it's not anything you can't learn to do with practice. Just have to learn your car.