Automatictire 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 flexmore under load, produci n g 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 p ercent to one percent. Heat and stress from improper inflation soften an d deflect tire components,
c ausing faster and more uneven wear, whic h shortens the life of thetire. Under inflated tires have
more frequ ent 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
werewithin 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 ti g ht. This is because air molecules can permeate through tires. Temperature an d load also affect tire pressure. For these reasons, t ir e 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 b ulk of the load is carried in the tra iler, a 10-psi under inflation in a trailer tire ma y have nearly twice the impact on truck fuel econom y as the same amount of under inflation in a drive tire. Despite the importance of keepi ng trailer tires properly inflated, a fleet may not be able to inspect its trailers regularly. A trailer may be gone from th e serviceyard for

extended periods of time while on the road, at a customer’s facility or at dro p-o ff 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 resp onsib ility for checking tire pressure onto drivers. However, one industry survey indicates only eightpercent of truck

drivers checktire pressure with a tire gauge before each trip. 

## What is the solution? Au tomatic tire inflation (ATI) systems monitor a n d continuallyadjust 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-conta in ed compressors mounted on each hub that are powered by the rolling moti on o f the wheels. Once an ATI system is installed, it should n ot require any special attention from the driver.


## The results are in . . . ATI syste ms c an extend tire life by eight percent or
more. The systems eliminat e the n eed to check tire pressure manually, saving time a nd la bor while
e nsuring con sistent and proper tire inflation. Installing
an ATI system on a truck’s driv e axlesand trailer costsup to$900, but can save over $200 annually in tire maintenance costs. For a t ypical long-haul combination truck, annual fuel savi ng s could reach 100 gallons, saving $170 in fuel costs and eliminating
one m etr ic ton of greenhouse gas emissions. The costof 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 f r om reducing the risk of expensive tire failure caused by under inflation.


## Next steps Line-haul carriers that find it too difficult or expensive t o monitor tire pressure on a regular basis should consider installing auto matic tire pressure inflation systems on drive and trailer tires. ATIs can be readily retrofitted ontoexisting trucks and trailers. Interested fleetscan check wi th ATI manufacturers and truck and tire dealers for moreinformation. Fleets may also
con tacttire manufacturers or their state or nation al trucking associations for more information about the benefits of proper tire inflation.