Glossary

Load index

Last reviewed: 2026-05-20

A numeric code appearing in a tire's service description that corresponds to a specific maximum load capacity in a published table. Commercial truck tires typically use a two- or three-digit load index — for example, "149/146" on a dual-rated tire, where the first number is the single-service index and the second is the dual-service index. The actual load capacity in pounds for each index number is found in the published load index table. For commercial truck applications, the load range designation often provides more direct decision-making information, but the load index is part of the complete service description used to verify the tire is correct for the application.

Look up the load index through reliable tire data — the manufacturer's catalog, load index table, or the tire data book — especially when comparing tires from different brands or replacing a single tire in a matched set. The same load index number on a steer application and a dual application means different things: use the single index for steer and the dual index for drive or trailer dual positions. Mixing tires with different load indexes in a dual set can create unequal load sharing even when sizes appear identical.

Real-World Use

A dispatcher receives a photo of a replacement tire being considered at a remote location. The sidewall shows a load index different from the tire currently on the truck. The dispatcher uses the photo as a first check but does not approve the tire remotely — instead, the truck is routed to the nearest company-approved shop where a technician can verify the full service description and manufacturer data against the axle load before mounting. The load index difference in the photo was enough to flag the substitution for review rather than accepting it on the road.

What to Pair It With

Read this term with the full tire sidewall, vehicle rating information, manufacturer documentation, and the actual condition of the tire.

This site is for general information only. It does not replace professional tire service, DOT compliance advice, tire manufacturer instructions, vehicle manufacturer recommendations, or fleet policy.