305/30R21 in Inches

A 305/30R21 tire has a 28.2-inch diameter, a 12-inch width, and is designed for a 21-inch rim.

In high flotation terms, this tire is labeled as 28.2x12R21.

305/30R21 Tire Size
12"
28.2"
305/30R21 Tire Size in Inches
305/30R21 Tire Circumference
88.6"
21"
3.6"
715.1 revs/mile

305/30R21 Tire Overview

Height
28.2 inches
Wheel Diameter
21 inches
Tire Width
12 inches
Circumference
88.6 inches
Sidewall Height
3.6 inches
Revolutions
715.1 per mile
Tirelib.com

What does 305/30R21 mean?

305/30R21 tire size meaning in inches

305/30R21 is a tire size with the following dimensions:

  • 305 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.
  • 30 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.

305/30R21 Tire Conversion

DimensionsInchesMillimeters
Tire Diameter28.2 in716.4 mm
Section Width12 in305 mm
Rim Height21 in533 mm
Sidewall Height3.6 in91.5 mm
Circumference88.6 in2250.6 mm
Revolutions715.1 revs/mile
Not the tire size you are searching for? Try our Tire Size Calculator.

FAQ About 305/30R21 Tire

How tall is a 305/30R21 tire?

The height (or diameter) of a 305/30R21 tire is 28.2 inches

How wide is a 305/30R21 tire?

The width of a 305/30R21 tire is 305 mm, which is about 12 inches.

What size rim fits a 305/30R21 tire?

A 305/30R21 tire fits on a rim that is 21 inches in diameter.

What does the 30 in a 305/30R21 tire mean?

The 30 in a 305/30R21 tire refers to the aspect ratio, meaning the height of the tire's sidewall is 30% of its width.

Alternative Tire Sizes for 305/30R21

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 305/30R21:

Tire SizeDiameterRim
235/35R2127.5″ (-2.5%)21 x n/a
245/35R2127.8″ (-1.4%)21 x 8.0-9.0
245/40R2128.7″ (1.8%)21 x 8.0-9.5
255/35R2128.0″ (-0.7%)21 x 8.5-10.0
255/40R2129.0″ (2.8%)21 x 8.5-10.0
265/35R2128.3″ (0.4%)21 x 9.0-10.5
275/30R2127.5″ (-2.5%)21 x 9.0-10.0
275/35R2128.6″ (1.4%)21 x 9.0-11.0
285/30R2127.7″ (-1.8%)21 x 9.5-10.5
285/35R2128.9″ (2.5%)21 x 9.5-11.0
295/30R2128.0″ (-0.7%)21 x 10.0-11.0
315/30R2128.4″ (0.7%)21 x 10.5-11.5
325/25R2127.4″ (-2.8%)21 x 11.5-12.5
325/30R2128.7″ (1.8%)21 x 11.0-12.0
355/25R2128.0″ (-0.7%)21 x 12.5-13.5