Tire Sizing & Technical Data

Tire Sizing Explained

The earliest tire designs, known as Type I, emerged in the 1930s. These were referred to only by their outside diameter, such as 27″, which was a common fitment for aircraft like the Harvard or P51 Mustang.

General aviation tires are typically Type III designs and include commonly used sizes such as 5.00-5, 6.00-6, 8.50-6, and others. From this data, you can determine the tire’s width and the wheel size it fits, but not the outside diameter. For example, a 5.00-5 tire has a cross-section width of 5” and fits a 5” wheel.

Three-Part Name sizes cover most of today’s designs and typically describe the Outside Diameter, Section Width, and Wheel Size. For instance, a typical size like 15×6.00-6 means the tire is 15 inches tall, 6 inches wide, and fits a 6-inch wheel. Some tires in this classification are preceded with an ‘H’, indicating a higher percentage of deflection.

Metric sizes are the same as Three-Part Name sizes, but the Overall Diameter and Section Width are given in millimeters, while the rim sizes remain in inches. For example, a 380×150-5 tire has an imperial equivalent of 15×6.00-5.

Radial tires also follow the Three-Part Name size format, but the dash preceding the rim diameter is replaced with the letter ‘R’. For example, 26×6.6R14.

Aircraft tires are generally serialized, though some general aviation and tailwheel sizes may not be. Most have 8 digits in the serial number, using the Julian calendar. For example, the serial number 92561234 can be deciphered as follows: (9) indicates 2019 production, (256) is the day of the year of production, and the last four characters indicate serialization for the tire size/PR during its production run.

Aircraft inner tubes may be used in Aircraft Tubeless tires. Markings on the tire may include TT for Tube Type, TL for Tubeless, and TL/TT for a dual-use tire that can be used on both tube and tubeless wheel designs.