315/45R21 in Inches

A 315/45R21 tire has a 32.2-inch diameter, a 12.4-inch width, and is designed for a 21-inch rim.

In high flotation terms, this tire is labeled as 32.2x12.4R21.

315/45R21 Tire Size
315/45R21 Tire Size in Inches
315/45R21 Tire Circumference
627.1 revs/mile

315/45R21 Tire Overview

32.2 inches
Wheel Diameter
21 inches
Tire Width
12.4 inches
101 inches
Sidewall Height
5.6 inches
627.1 per mile

What does 315/45R21 mean?

315/45R21 tire size meaning in inches

315/45R21 is a tire size with the following dimensions:

  • 315 is the width of the tire in millimeters. This number also indicates the appropriate width of the rim on which the tire should be mounted.
  • 45 is the aspect ratio, which is the ratio of the tire's height to its width. This affects the tire's handling and ride comfort
  • R indicates the tire's construction type, meaning it has a radial construction. This provides stability and precision to the tire.
  • 21 is the diameter of the wheel in inches, on which the tire is to be mounted.

315/45R21 Tire Conversion

Tire Diameter32.2 in816.9 mm
Section Width12.4 in315 mm
Rim Height21 in533 mm
Sidewall Height5.6 in141.8 mm
Circumference101 in2566.4 mm
Revolutions627.1 revs/mile
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FAQ About 315/45R21 Tire

How tall is a 315/45R21 tire?

The height (or diameter) of a 315/45R21 tire is 32.2 inches

How wide is a 315/45R21 tire?

The width of a 315/45R21 tire is 315 mm, which is about 12.4 inches.

What size rim fits a 315/45R21 tire?

A 315/45R21 tire fits on a rim that is 21 inches in diameter.

What does the 45 in a 315/45R21 tire mean?

The 45 in a 315/45R21 tire refers to the aspect ratio, meaning the height of the tire's sidewall is 45% of its width.

Alternative Tire Sizes for 315/45R21

Typically, it's recommended to choose a tire with a diameter (height) within 3% of the original equipment manufacturer (OEM) tire size.

However, keep in mind that this is a general guideline and not an absolute rule.

Here are some tire sizes that are compatible with the 315/45R21:

Tire SizeDiameterRim
275/50R2131.8″ (-1.2%)21 x 7.5-9.5
275/55R2132.9″ (2.2%)21 x 7.5-9.5