Smooth_J

Does anyone know how to calc revs per mile on the tire?

Thank you!!!

sitnlopro99gt

this should work http://www.gordon-glasgow.org/tirecalc.html

Smooth_J

I tried that site, but same issue.

According to the site, or any other site that I have found - 245/45 R17 would give 785 Revs, but according to tire rack its 811?!

Revs per mile = 20168 / tire diameter (25.68)
Revs = 785.358 (or 785)

I tried different tires - same issue Please help!

sweet99

I think the difference is caused by a tire inflated to spec and the same tire with your car's weight on it. With the tire mounted it will have a smaller diameter. mark

Colorado_Mustang

Tires will grow a little bit at higher speeds. Any calculation for rev's per mile will be based on the theoretical circumferance of the tire based on its size. If you want to know for sure, measure the circumferance of your tire and divide it into 63360 (5280 feet times 12 for inches).

wisk

Yeah I know this thread has been dead and all, but the calculator didn't work for me as well.
275/35R18, supposed to be 788 revs. I was driving behind my buddy today in his new focus, called him up real quick to double check the speedos, and while there was no noticeable visual difference in our distance apart, he said he was going 61mph while i was going 69mph. Guess I'll just have to piddle on the tuner with it.