Pirelli Slick size questions

[Dr.Ron]

Does anybody have any experience in the sizes. I am concerned about the diameter delta and not creating any AH or TC issues or limp mode on track with the computer.

I run 315/345 Hoosiers with no issues. Trying to avoid or prolong a shift to 5th gear an NJMP tracks. I figure the car has enough torque to handle the increased diameter.

The 325 705 18 Pirellis are 27.7 while the 325 660 18 has a diameter of 26.1 (delta of 1.6). Hooisers are 25.6F and 26.8R so delta is 1.2.
Then there are the 315 680 18 Pirellis at a diameter of 26.8. Those with the 325 705 have a delta of 0.9.

Are other sizes better? Trying to keep the widest tread width too.

Thanks!

Ron

[Racingswh]

Does anybody have any experience in the sizes. I am concerned about the diameter delta and not creating any AH or TC issues or limp mode on track with the computer.

I run 315/345 Hoosiers with no issues. Trying to avoid or prolong a shift to 5th gear an NJMP tracks. I figure the car has enough torque to handle the increased diameter.

The 325 705 18 Pirellis are 27.7 while the 325 660 18 has a diameter of 26.1 (delta of 1.6). Hooisers are 25.6F and 26.8R so delta is 1.2.
Then there are the 315 680 18 Pirellis at a diameter of 26.8. Those with the 325 705 have a delta of 0.9.

Are other sizes better? Trying to keep the widest tread width too.

Thanks!

Ron

Hi Dr. Ron,

Just saw this thread. I am sure you are on the right track. My Viper does 148 MPH on the nose in 4th using the 31/71/18 Michelin. I think the Pirelli is a smidge shorter but you will still see 145 mph in 4th I believe. That definitely helps.

If you go with the taller tire I believe you can avoid 5th gear at either NJMP track. As you obviously have found out the Hoosier 345-35-18 is too short and 5th gear will be used at nearly every track you will go to.

Steve

[Dr.Ron]

Thanks Steve. I ordered the 325 705 18 and 305 645 18 pirellis from Todd at GTracing tires after we emailed.
Ron