Tire growth @150.

[TMSJoe]

Putting a Ford 9 inch in my fathers 1967 Chevelle this winter. I need to pick a gear. I have data with different tires but this new tire I don't. We have Quick Time Pro D.O.T., LT 31 x 18.5-15. Looking to find out how much they grow at 150 MPH. This is a stick car so the numbers usually add up.

[Rick!]

It’s still a bias ply slick with stiff sidewalls. Conservative growth would be 5% of the circumference. So, 150mph with a 97” rolling circumference tire is about 1633rpm. 5% growth would be 1551rpm.