Originally Posted by tyler85
What about a 265/70/17?? I'm sorry for asking but trying to figure out the right millimeter for my edge is so confusing. I think the millimeters typed in right now may be off a little because my speedo is a tad off from my edge speedo. Any help would be appreciated!
Rim Dia. Calculation 17 * 25.4 = 431.8mm
Tire Sectional Dia.. Calculation 265 * .70 = 185.5 * 2 = 371
Total Dia. 431.8 + 371 = 802.8mm
Circumference 802.8 * Pi 2522.07mm Round to 2522
Rolling circumference will be about 97% of the Hanging Circumference of a properly inflated tire, so 2522 * .97 = 2446.34 so 2446mm
I have been using this since before I found the video. He calculates in Inches, but Just apply the Ratio to the Millimeters for your Rolling Circumference.
My calculated is 2646(275-70/18) but my edge reads dead on to mt GPS at 2604, and my Custom tune for my size came from Power hungary at 2567(which is 97%) but I air my tires high 65-70 PSI since they are 80psi Tires.