[bobss396]

You would have to really inflate a tire to an unsafe pressure to get more circumference out of it. It will be measurably larger.

You could do some backward calculations on a speed chart to determine the size delta that you would need to achieve your numbers.

We used to stretch stock car tires to get a desired "stagger set" size if we needed it. Not at all recommended, but we would inflate the tire to around 60 psi and leave it in the sun all day. Right before we would use it, the air pressure would be brought back to normal. We would pick up around .5 to 1 inch of circumference. Precautions were taken to lessen chances of personal injury.

Bob