Tire Inflation for Towing vs Speed: How to Balance

Load capacity and inflation pressure

The load rating of a tire is defined as the maximum load a tire is rated to carry at a given inflation pressure. A higher inflation pressure increases the load capacity, up to the maximum permissible inflation pressure, which is the maximum cold inflation pressure to which a tire may be inflated.

The vehicle manufacturer specifies a recommended cold inflation pressure for normal driving conditions, based on the vehicle's gross axle weight ratings and the distribution of load. This pressure is found on the placard in the driver's door jamb, as explained in our tire pressure basics.

Why towing and high speed both demand higher pressure

Towing adds load to the rear axle (or to the trailer axles). The vehicle maximum load on the tire must not exceed the tire's maximum load rating at the operating pressure. Because load rating increases with inflation pressure, you need to raise the pressure to gain enough load capacity for the heavier axle.

High-speed driving also increases the stress on tires. Heat builds up more quickly, and under-inflated tires flex more, which worsens that heat. While the exact relationship between speed and required pressure depends on the tire and vehicle, the principle is the same: more speed and more load call for more pressure, not less.

However, you must not exceed the maximum cold inflation pressure molded on the sidewall. Exceeding that limit can lead to premature wear and even tire failure.

How to set the right pressure for towing or speed

Start with the vehicle manufacturer's recommended cold inflation pressure from the door placard. This is the baseline for normal, unloaded driving. For towing, you need to determine the actual load on each axle, then find the inflation pressure that gives a load rating at or above that load. The tire sidewall lists the maximum load rating at the maximum permissible inflation pressure, and load rating tables from the tire manufacturer show values for intermediate pressures. If you cannot locate the table, you can increase the pressure in steps and compare the load rating to the axle load, but always stay below the maximum.

For sustained high-speed driving, the placard pressure is often sufficient for an unloaded vehicle. If you are also carrying a heavy load, use the towing pressure. The TPMS will warn you if pressure drops to 25 percent below the vehicle's recommended pressure, so a higher starting point gives you more margin before the warning triggers.

Check the pressure when the tires are cold, before driving. For a more detailed guide, see our towing tire pressure adjustment article.

The trade-offs between pressure, wear, and fuel economy

Higher inflation pressure reduces rolling resistance, which improves fuel economy. According to the U.S. Department of Energy, properly inflated tires can improve gas mileage by 0.6% on average, and under-inflated tires lower gas mileage by about 0.2% for every 1 psi drop in the average pressure of all tires.

On the other hand, too high a pressure can reduce the tire's contact patch, leading to center tread wear and a harsher ride. Too low a pressure increases sidewall flex, generates heat, and can cause shoulder wear or even blowout. The right balance is to use the pressure that provides adequate load capacity without exceeding the manufacturer's maximum.

If you drive with a variety of loads, it may be worth using a tire with a higher load range, such as a light truck (LT) tire, which can handle more load at a given pressure. Look at the best light truck tires Alternatively, if you often tow a trailer, consider a dedicated trailer tire. View best trailer tires

Balancing towing and high speed in practice

The simplest rule is to set your tire pressure for the heaviest load and the highest speed you expect to encounter on a given trip. If you tow a trailer at highway speed, the pressure that covers the trailer's axle load and the towing vehicle's rear axle load is the correct one. Once you are towing, do not lower the pressure to soften the ride; that can lead to dangerous heat buildup.

For unloaded, high-speed cruising, the placard pressure is usually sufficient. If you notice the tires are running hot or the steering feels vague, you may need to add a few psi, but never exceed the sidewall maximum. The trade-off between comfort and load capacity is inherent, and you can only get one or the other at the extremes.

Remember that the TPMS is set to the vehicle's recommended pressure, not to your towing pressure. If you increase pressure for towing, the TPMS will still warn based on the original threshold, which is actually safer because it gives you an earlier warning. Learn more about tire pressure and TPMS.

Special cases: LT tires, ST tires, and trailers

Light truck (LT) tires are designed for heavier loads and have load/inflation tables that differ from passenger car tires. They are a good choice for frequent towing. See the best light truck tires

Special trailer (ST) tires are for trailers only and have their own load and pressure requirements. Always use the pressure recommended for the trailer tire and check it before every trip. Find the best trailer tires

If you are using a pickup truck for towing, you may need to adjust the rear pressure more than the front, because the rear axle carries more of the tongue weight. Review towing considerations

What to pick for your use

Questions

Should I lower tire pressure when towing to get a smoother ride?

No. Lowering pressure under load increases heat and can lead to tire failure. You should increase pressure to support the load, not soften the ride.

Can I use the maximum sidewall pressure for all driving?

No. The maximum is a limit, not a target. Use the pressure that matches the load and speed, and never exceed the sidewall maximum.

How often should I check pressure when towing?

Check cold pressure before each trip and periodically during long trips, since heat can raise pressure. Use a reliable gauge and check when tires are cool.

Does high speed require lower pressure to keep tires cool?

No. Lower pressure increases flexing and heat. Higher pressure is usually safer at speed, but stay within the tire's maximum.

What is the difference between the placard pressure and the sidewall pressure?

The placard gives the vehicle manufacturer's recommendation for normal load, while the sidewall lists the maximum cold inflation pressure and maximum load rating. Use the placard as a baseline and adjust upward for load.