I am going to use Dunlop ZII tires for autocross this season. The 215-40-17's won't be available until the first week of March. I am doing an Evolution Driving school in March and if I wait for the 40 series its possible I won't have them for the driving school.

A few questions...

1. Is a smaller tire that much of an advantage for autocross, or with the JCW that has so much low end torque is it not that noticeable to use a taller tire?

2. Its my assumption that I would get a lot more out of the experience if I use the same tire that I will have all season. Does that thinking make it worth it to go with the 215-45-17 to ensure I can attend the school on the same tire I will use later on?

3. Am I making to much of a deal about the diameter difference between the two?

 

What class are you running in I wonder?

Just to share the complexity of the street tire scene this year, here's a resource...

Cheers,

Charlie

 

D stock

 

I doubt if the difference will be noticeable at all if you don't look at the timer. On the other hand, tenths of a second become important in a competitive autocross. Personally, I would want the new tires scuffed in for the school.