Understanding Your Tires

Service Description

Your tire's load capacity is a critical factor when it comes to safe operation and must properly match up with axle capacities and your overall loaded vehicle weight. This 'Tire Tips' video shows how to ensure that your tire and axle configuration follow the specs that came with your truck.

To avoid overloading tires, maintain the proper inflation pressure and never exceed the vehicle’s load capacity, Gross Axle Weight Rating (GAWR) or the Gross Vehicle Weight Rating (GVWR) of your vehicle. The vehicle must also be distributed so that no individual axle, tire or dual assembly is overloaded. Never exceed the maximum load rating stamped on the sidewall of your tire, and never exceed the maximum load or inflation pressure capacity of the rim or wheel assembly. Consult the vehicle tire information placard, certification label and owner’s manual for the recommended vehicle load limits and loading requirements.

A tire’s load capacity and speed limits are indicated by the tire service description located on the sidewall.
Size & Service

Load Index
The load index indicates how much weight a tire is capable of carrying safely (Single/Dual).

Load Index


Driving your vehicle in an overloaded condition is dangerous. Overloading causes excessive heat build-up and internal structural damage. This may cause a tire failure, including a tread/belt separation, even at a later date, which can lead to an accident and serious personal injury or death.

Speed Category 
The maximum speed indicates the top speed at which the tires are designed to operate safely. Regardless of the speed capability of your tires, never exceed lawful speeds or speeds dictated by driving conditions. Exceeding a tire’s speed capacity could cause overheating and sudden tire failure.

Speed Category

Tire Spinning
  • Do not allow the reading on the speedometer to exceed 35 mph if tires are spinning because the vehicle becomes stuck in mud, snow, ice, etc. When only one tire on an axle is spinning, its speed can be up to four times what is indicated on the speedometer and can quickly exceed the capability of the tire.
  • Never allow anyone to stand near a spinning tire. Speed and force can cause a tire to rupture and explode and may cause property damage, serious personal injury or death to you or a bystander. Property damage, serious personal injury or death may result from tire failure due to excessive tire spinning.

Related Information

Understanding Your Tires

Reading a Sidewall
Tire Dimensions