315/70R15 in inches

315/70R15 — what does it mean?

• 315 stands for tread width in millimeters
• 70 is an aspect ration between the tread width and the sidewall in percents
• R means that the tire has a radial construction
• 15 is a wheel diameter (or rim) in inches

How to convert 315 70R15 to inches?

First of all, we need to divide 315 mm (width) by 25.4 (mm to inch conversion), which will give us a width of 12.4″. Then, 70% of the 12.4″ will result in 8.7″ sidewall.

To get the total height or tire diameter, we need to sum the 15″ rim diameter with two of the sidewall heights. It will result in a 32.4″ total tire diameter (or height).

For your convenience, below is a table for 315/70R15 conversion to inches:

Alternatives to a 315/70R15 tire

If you're looking to upsize your 315 70R15 tires, try to stay within 3% deviation of an overall diameter for safety reasons.