11-10-2015, 07:32 AM
736,
You'll have to forgive me if this is more than you bargained for. Tire sizes work like this:
A 140/70-18 has a 140mm wide tire, with a 70% aspect ratio meaning the sidewall is 70% of the width, on an 18" rim. To find the total diameter use this equation
D = 2 x width x aspect ratio / 25.4 + rim size in inches.
You multiply by 2 to account for both sidewalls on (top and bottom across the diameter) and divide by 25.4 to convert mm to inches. That being said....
160/60-18 = 2*160*.6/25.4 + 18 = 25.56"
the 140/70-18 = 2*140*.7/25.4+18 = 25.72"
Difference is 0.16" overall.
You'll have to forgive me if this is more than you bargained for. Tire sizes work like this:
A 140/70-18 has a 140mm wide tire, with a 70% aspect ratio meaning the sidewall is 70% of the width, on an 18" rim. To find the total diameter use this equation
D = 2 x width x aspect ratio / 25.4 + rim size in inches.
You multiply by 2 to account for both sidewalls on (top and bottom across the diameter) and divide by 25.4 to convert mm to inches. That being said....
160/60-18 = 2*160*.6/25.4 + 18 = 25.56"
the 140/70-18 = 2*140*.7/25.4+18 = 25.72"
Difference is 0.16" overall.