Tire Weight Limit

Tire Width

You cannot exceed tire rating or state posted limit for the max load on a tire, for example in some state it is 650 pounds per inch of tire width. Many states have different limits and some states have different tire weight limits for steer axles.

Move the slider to see an interactive animation

The normal tire weight rating is established by the manufacturer and the states per inch rule for the tire width. As tire width increases, weight allowance also increases by both the manufacture and state law.

Number Of Tires

The more tires you have, the higher is your weight limit for that axle based on the tire weight rating, as you’ll be multiplying the tire weight limit * tire width * number of tires

Move the slider to see an interactive animation

Single tires are the easiest to maneuver and usually used for the steer axle. As in the example above, 650 pounds per inch on a standard 11” tire on an axle with one tire on each side will get you a 650*11*2=14,300 pounds limit on that axle.

#2 Axle and Axle Group Limits

Every state has limits for a max single axle and each axle group weights.

Axles in the axle groups are almost always given a lower weight per axle than if they were single axles, e.g. a single axle in texas can carry 25,000 pounds, but a tandem (two axles in a group) can only carry 46,000 pounds, so 23,000 per individual axle in that tandem.

The axles or axle groups are:

Steer Axle: The steer axle provides directional control through the driver’s steering wheel, it's usually the first axle with only a single tire on each side, so it is almost always limited by the tire weight limit and can carry a much lower weight. You can get more weight by putting a wider tire on the steer, but overloading the steer makes steering harder.

Example of a steer axle

Single Axle: Single axle is an axle spaced enough apart from other axles to not be considered to be in a group

Example single axle on a booster

Tandem Axle: A tandem axle describes two axles spaced more than 40” but not exceeding a certain limit that is different in many states. Distances are measured from the centers of the two axles. Note: two axles spaced less than 40 inches apart are considered a single axle. Tandem axles may be drive axles.

Example tandem on a lowboy trailer

Tridem Axle: A tridem axle is made up of three consecutive axles spaced within a state posted limit of each other

Example tridem on an rgn

Quad Axle: A quad axle is made up of four consecutive axles spaced within a state posted limit of each other

Example quad axle on an extendable step deck trailer

Note: Axle groups of five and more axles may be used when hauling certain loads. These are uncommon special cases and not all states specify weight limits for five and over axle groups.

Axle Spacings

Axle groups above are determined based on the distance between the axles and are different in many states. Sliding axles apart will give you a higher weight.

Federal regulations for a normal tandem allows 34K based on the Federal Bridge Formula (the standard for all commercial vehicles). Most states will allow you more than that with a permit.

Axle Type

Some states consider steer and drive axles as a different type of axle and will give you a higher or a lower limit on them. For example many states will give you a different tire weight rating for the steer.

Always make sure to check if there is a different steer weight limit or tandem drive axle limit posted by the state.

Frost Laws

During the spring thaw, the roadbed is softened by moisture trapped beneath the pavement, reducing the supporting strength of the road to less than the original construction strengths. For that reason during spring, the northern states significantly reduce the permitted allowable weights.

Always make sure to research the frost laws of the state you go through during spring months. You can find that information on our frost laws by state page.

Axle Weight Regulations And Limits By State

Now that you understand what is involved in determining state limits, you can use the map below to lookup specific state regulations or use the calculator below.Every US state and Canadian province has its own regulations concerningoverweight loads and must be researched. Each has available literature that it provides to help you make an informeddecision about how to configure your equipment or disperse your load weight while traveling on their roadways.