Tire Pressure for Load: Using the Load and Inflation Table

What a load and inflation table shows

A load and inflation table is a chart that pairs cold inflation pressure with the maximum load a tire can support at that pressure. Federal regulations define load rating as the maximum load a tire is rated to carry for a given inflation pressure, and this definition appears in standards for both light and heavy vehicles. For example, 49 CFR 571.139, which covers new pneumatic radial tires for light vehicles, uses that exact wording. The table simply presents those ratings for each tire size in an easy to read format.

The table is not the same as the pressure recommendation on your vehicle placard. The placard gives the pressure for the vehicle's normal load, determined by the manufacturer. The load and inflation table shows the full range of loads the tire can handle as pressure changes. You need the table when you plan to exceed the normal load, such as when towing, hauling cargo, or carrying many passengers. Before diving into the table, review the basics of tire pressure and understand how the load index rating relates to actual capacity.

Why pressure changes with load

Pressure and load capacity are directly linked. At a given inflation pressure, a tire has a maximum load it can safely support. If you inflate to a higher pressure, the tire can carry more weight, as long as you stay below the maximum permissible inflation pressure molded on the sidewall. Conversely, running at too low a pressure for the actual load causes excessive flexing, heat buildup, and potential failure.

Federal safety standards also set a margin for normal driving. Standard 571.110, which covers tire selection for vehicles with a gross vehicle weight rating of 10,000 pounds or less, requires that the vehicle normal load on the tire not exceed 94 percent of the load rating at the recommended pressure. This leaves a buffer for load shifts and minor pressure loss. Keeping tires properly inflated also affects fuel economy; the U.S. Department of Energy's fueleconomy.gov notes that under-inflated tires can lower gas mileage by about 0.2 percent for every 1 psi drop in the average pressure of all tires. For a deeper look at how load and speed interact, see our guide on tire speed and load requirements and the factors in tire vehicle load inflation.

Determining the load your tires actually carry

Before you can use a load and inflation table, you need to know the weight each tire supports. The regulations define two useful terms. Vehicle maximum load on the tire is the load on an individual tire when the vehicle is at its maximum loaded weight, distributed per axle and divided by two. Vehicle normal load on the tire is the load at curb weight plus accessory weight and normal occupant weight, again divided by two.

To find your actual load, you can weigh the vehicle on a scale, or use the gross axle weight rating (GAWR) from the certification label. For a single tire on an axle, divide the axle load by two. For dual wheels, divide by four. If you are towing, the tongue weight of the trailer adds to the rear axle load. Always use the worst case, such as a full tank of fuel and all passengers, when choosing pressure. You can also reference a tire load capacity chart to see how these numbers are derived from the sidewall markings.

• Weigh each axle separately at a public scale.
• Use the GAWR from the vehicle label if you know the loaded weight is below it.
• For trailers, include the tongue weight on the tow vehicle's rear axle.

How to read the load and inflation table

The table is organized by tire size and load index. Your tire sidewall shows the size, such as 265/70R17, and the load index, a number like 115 or 121. The load index corresponds to a specific load capacity at a reference pressure, but the full table provides ratings for many pressures. For LT (light truck) tires, the table is often printed on the sidewall in small text. For P-metric tires, you may need to find it in the owner's manual or from the tire manufacturer's published data.

Once you have the table, locate your tire size and load index. The columns list inflation pressures, typically from about 30 psi up to the maximum for that tire. The rows show the load rating at each pressure. Find the pressure where the listed load rating is equal to or greater than the actual load you calculated. That is the minimum pressure you should use for that load.

Never set the pressure lower than the value from the table for your load, even if the placard says a lower number. Conversely, never exceed the maximum permissible inflation pressure on the tire sidewall. The table may also be expressed in kilopascals (kPa) in some regions; convert carefully if needed. Understanding the sidewall markings will help you locate the load index and maximum pressure correctly.

• Identify the tire size and load index from the sidewall.
• Obtain the correct table from the tire manufacturer or an industry standard.
• Find your tire size in the table, then locate the row for your actual load.
• Read the corresponding inflation pressure and set it using a cold tire.

Setting pressure for heavy loads and towing

When you increase the load on your vehicle, you must increase the tire pressure accordingly. For example, if your normal placard pressure is 35 psi but your rear axle is loaded near its GAWR, you may need to inflate the rear tires to 40 or 45 psi, depending on the table. The door placard is only valid for the vehicle's designed normal load, not for towing or heavy cargo.

LT tires are built for heavier loads and have higher load ranges. If you regularly tow or carry heavy payloads, consider a tire with a higher load index or an LT construction. Many light trucks and SUVs come with P-metric tires, but the vehicle may be certified for LT tires as an option. Check the tire and rim matching information required by FMVSS 571.110 to ensure the rims are compatible. For heavy trailers, ST (special trailer) tires have their own tables and should only be used on trailers. If you're selecting tires for heavy-duty use, explore our picks for light truck tires and trailer tires to find suitable options.

Safety rules and common mistakes

The Federal Motor Vehicle Safety Standards prohibit operating a vehicle with tires that are overloaded relative to their inflation pressure. Standard 571.110 states that the vehicle maximum load on the tire must not be greater than the maximum load rating marked on the sidewall. For vehicles over 10,000 pounds GVWR, Standard 571.120 has a similar requirement: the sum of the maximum load ratings of the tires on an axle must not be less than the GAWR.

A common mistake is using the maximum pressure printed on the sidewall as a daily setting. That pressure is the upper limit, not a recommendation. Another mistake is ignoring the load table and running the placard pressure when heavily loaded. Always inflate to the pressure from the table for the actual load, but do not go above the sidewall maximum. Check the pressure when the tires are cold, and remember that the TPMS only warns of significant under-inflation, not overload. Learn more about TPMS systems and how tire construction types affect load capacity.

What to pick for your use

Questions

What is a tire load and inflation table?

It is a chart that shows the maximum load a tire can carry at each cold inflation pressure. The values are defined by tire standards and let you match pressure to your actual load rather than relying on the vehicle placard alone.

Where do I find the load and inflation table for my tire?

For LT tires, the table is often printed on the sidewall. For P-metric tires, check the owner's manual, the tire manufacturer's website, or industry publications like those from the Tire and Rim Association. The tire sidewall lists the size and load index that identify the correct table.

Can I use the pressure on the tire sidewall for heavy loads?

The sidewall maximum pressure is the upper limit, not a recommended setting. You should use the pressure from the load and inflation table that matches your actual load, but never exceed that maximum. The sidewall pressure may be needed only for the highest possible load the tire can carry.

How do I know the actual load on each tire?

Weigh each axle at a scale and divide by two for a single tire per side, or by four for duals. Use the GAWR from the vehicle certification label if the vehicle is loaded near its limit. Always include the tongue weight of a trailer on the rear axle.

Is it legal to exceed the maximum pressure on the tire sidewall?

No. Federal regulations define maximum permissible inflation pressure as the maximum cold pressure that a tire may be inflated to, and exceeding it violates FMVSS 571.110 or 571.120 depending on vehicle weight. The load table will not require pressures above that limit.