How to Measure Tires and Rims

Learn how to measure different types of tires and rims with the charts below. Maintain and repair tires with Gempler's selection of tire supplies ranging from air gauges & chucks, flat tire prevention supplies, tire changing tools, and much more.

Tire Sizes

Outside Diameter x Width x Rim Diameter

For Example: 18 x 8.50 - 8

A: 18" - Height of the tire; overall diameter
B: 8.5" - Width of the tire from sidewall to sidewall
C: 8" - Diameter of rim

Diagram of tire showing various measurement locations

Industrial Tire & Wheel Assemblies

Example:
4.80 x 8 Wheelbarrow tire assembly

OD: 16"
Hub Length: 6"
Axle Shaft: 5/8"

Wheel Offset

Positive Offset: A wheel with a positive offset moves the tire and wheel closer to the frame.

Rim Diameter & Width

Diameter: Rim diameter is measured from tire
bead seat area to tire bead seat area

Width: Rim width is measured from tire bead
seat area to tire beat seat area

Diagram of rim showing diameter and width measurement locations

ATV Tires

Example size: 20 x 7 - 8

A: 20" Height of tire overall diameter
B: 7" - Width of tire from sidewall to sidewall
C: 8" - Diameter of rim

Agricultural Wheels

Correct Way to Measure the Bolt Pattern of a 5 Bolt Wheel : Measure from center on one bolt hole straight across the wheel to the center of the two opposite bolt holes