The results of this calculator are based on the mathematical equations of the sizes entered, not the actual tire specs provided by the tire manufacturers. Please refer to the guides supplied by manufacturers for exact specifications. Not for use with high flotation sizes, i.e. 31x10.50R-15. Fill out this section if you would like specs on just one tire size. What size is being run now? /   R-   Would you like to compare it to another size? Enter new size below. What size would you like to run? /   R-   Results Totals are in inches Tire 1 Tire 2 Difference Sidewall Height: Section Width: Overall Diameter: Circumference: Revs per mile: If your speedometer reads:   20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 You're going approximately: