Automatic tire inflation systems can save tire maintenance costs and improve fuel economy by nearly 1%, saving

100 gallons of fuel and eliminating one metric ton of greenhouse gas emissions per year. Properly inflated tires

also wear longer and have fewer punctures.

What is the challenge?

When not properly inflated, tires flex more under

load, producing heat and increasing rolling

resistance, which wastes fuel. Truck tires inflated ten

pounds per square inch (psi) below recommended air

pressure levels can reduce truck fuel economy from

0.5 percent to one percent. Heat and stress from

improper inflation soften and deflect tire components,

causing faster and more uneven wear, which

shortens the life of the tire. Under inflated tires have

more frequent punctures, increasing the risk of tire

failures that could lead to costly road service and loss

of revenue.

Despite these costs, a recent survey of combination

trucks found that less than half the tires surveyed

were within five percent of the recommended inflation

pressure. Fleets may find it difficult to keep tires

properly inflated since truck tires can lose up to 2 psi

each month, even if the rim seal and valve stems are

tight. This is because air molecules can permeate

through tires. Temperature and load also affect tire

pressure. For these reasons, tire manufacturers

recommend checking tire pressure each week and

establishing a tire maintenance program. 

Even a good tire maintenance program may fall short

of its aims. In part, this is because trailer tires have

more impact on truck fuel economy than tractor tires,

yet trailers are interchangeable and thus harder to

monitor. Since the bulk of the load is carried in the

trailer, a 10-psi under inflation in a trailer tire may

have nearly twice the impact on truck fuel economy

as the same amount of under inflation in a drive tire.

Despite the importance of keeping trailer tires

properly inflated, a fleet may not be able to inspect its

trailers regularly. A trailer may be gone from the

service yard for extended periods of time while on the

road, at a customer’s facility or at drop-off location

waiting for a back haul. A fleet may not even own the

trailers it hauls, but pick them up from a shipper or

third party. These circumstances can place much of

the responsibility for checking tire pressure onto

drivers. However, one industry survey indicates only

eight percent of truck drivers check tire pressure with

a tire gauge before each trip. 

What is the solution?

Automatic tire inflation (ATI) systems monitor and

continually adjust the level of pressurized air in tires,

maintaining proper tire inflation automatically, even

while the truck is moving. One ATI system uses the

vehicle’s own air-brake compressor to supply air to all

the tires. Another system uses self-contained

compressors mounted on each hub that are powered

by the rolling motion of the wheels. Once an ATI

system is installed, it should not require any special

attention from the driver.

The results are in . . . 

ATI systems can extend tire life by eight percent or

more. The systems eliminate the need to check tire

pressure manually, saving time and labor while

ensuring consistent and proper tire inflation. Installing

an ATI system on a truck’s drive axles and trailer

costs up to $900, but can save over $200 annually in

tire maintenance costs. For a typical long-haul

combination truck, annual fuel savings could reach

100 gallons, saving $170 in fuel costs and eliminating

one metric ton of greenhouse gas emissions. The

cost of installing an ATI system in a line-haul truck is

generally recouped in just over two years through

fuel and maintenance cost savings. Truck fleets may

realize additional savings from reducing the risk of

expensive tire failure caused by under inflation.

Next steps

Line-haul carriers that find it too difficult or expensive

to monitor tire pressure on a regular basis should

consider installing automatic tire pressure inflation

systems on drive and trailer tires. ATIs can be readily

retrofitted onto existing trucks and trailers. Interested

fleets can check with ATI manufacturers and truck

and tire dealers for more information. Fleets may also

contact tire manufacturers or their state or national

trucking associations for more information about the

benefits of proper tire inflation.