Contour Enthusiasts Group Archives Forums Modifications Wheels & Tires looking for a website....

...that calculates at X mph how far off your speedometer is with different size tires. i remember seeing one it seems like it was a tire place like www.tires.com or something. when you punched in the tire size you want versus the stock ones, you can enter a mph and it will tell you how far off you are. can anyone help out? its actually for my father, he put 31" (31x10.5x15) tires on his f-150.

Here u go tire calculator

I have two pages. The first one will tell you percentage off, and the second does inches off (I think).

http://www.miata.net/garage/tirecalc.html

http://www.c5-corvette.com/tirecalc.htm

good stuff. thanx guys! i had the miata one but it wont let me enter in an oddball size like 31x10.5x15

i actually just found a cool site here where you enter in your original tire diameter, your new tire diameter, and the mph, and it will tell you how many mph you are off. i got the tire diameters from www.tirerack.com

Checkout
www.whalentire.com

pick your car and wheel size then click tires for current vehicle and they will show you the speedo reading for different plus tire sizes.

.......and another