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MENTAL PROTECTION AGENCY »
U.S. ENVIRONMENTAL PROTECTION AGENCY
Maintaining Proper Tire Inflation Pressure
A Glance at Clean Freight Strategies
ENERGY &
FUEL SAVINGS
Gallons Saved:
100 gallons
CO2 Savings:
1.02 metric tons
Fuel Economy
Increase:
.6%
MPG
(original 6 mpg):
6.04 mpg
Fuel Cost Savings:
$346
Maintaining proper tire inflation pressure can save tire maintenance costs and
improve fuel economy by nearly i percent, saving 100 gallons of fuel and eliminating
i metric ton of greenhouse gas emissions per year. Properly inflated tires also
have fewer punctures and a longer life expectancy.
What is the challenge?
When not properly inflated, tires flex more under load. This produces heat and increases
rolling resistance, which wastes fuel. Truck tires inflated 1 0 pounds per square inch (psi) below
recommended air pressure levels can reduce truck fuel economy between 0.5 percent and 1
percent.
Heat and stress from improper inflation soften and deflect tire components, causing faster and
more uneven wear, which shorten the life of the tire. Underinflated tires have more frequent
punctures, increasing the risk of tire failures that could lead to costly road service and loss of
revenue.
Despite the importance of proper tire inflation pressure, a recent survey of combination trucks
found that less than half the tires surveyed were within 5 percent of the recommended inflation
pressure. Another industry survey indicates only 8 percent of truck drivers check tire pressure with
a tire gage before each trip. One reason fleets may find it difficult to keep tires properly inflated
is that truck tires can lose up to 2 psi each month, even if the rim seal and valve stems are tight.
A fleet may not be able to inspect or monitor its trailer tires regularly due to the fact that extended
periods of time are spent away from service yards and because trailers are interchangeable. This
places greater responsibility for checking tire pressure onto drivers.
What is the solution?
One way to prevent tire pressure underinflation is for fleets to have tire maintenance management
systems in place to ensure that drivers and equipment maintenance personnel check tire pressure
at frequent intervals and fill tires that are underinflated. This can be made easier by the use of
electronic tire pressure monitoring systems that signal to drivers and maintenance personnel when
a tire becomes underinflated.
Automatic tire inflation (ATI) systems monitor and continually adjust the level of pressurized air in
tires, maintaining proper tire inflation automatically while the truck is in motion. One ATI system
uses the vehicle's own air-brake compressor to supply air to all the tires. Once an ATI system
is installed, it should not require any special attention from the drivers. This eliminates
the need to check tire pressure manually, which saves time and labor while ensuring
consistent and proper tire inflation.
There is some evidence that loss of tire inflation pressure can be slowed by
using nitrogen gas instead of air to inflate tires. While this method is not
recommended as a substitute for regular checks of tire pressure, testing by
the U.S. Department of Transportation has shown that nitrogen inflation
reduces the rate of pressure loss.
Savings and Benefits
ATI systems can not only extend tire life but truck fleets can also offer
additional savings from reducing the risk of expensive tire failure
caused by underinflation. Installing an ATI system on a truck's
drive and trailer axles costs up to $800. For a typical long-haul
combination truck, annual fuel savings could reach
Continued
U.S. EPA SmartWay | EPA-420-F-16-035 | June 2016 | www.epa.gov/smartway
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SmartWay
MENTAL PROTECTION AGENCY »
U.S. ENVIRONMENTAL PROTECTION AGENCY
Maintaining Proper Tire Inflation Pressure
A Glance at Clean Freight Strategies continued
100 gallons, saving $346 in fuel costs and eliminating 1 metric ton of greenhouse gas emissions. Annual tire maintenance costs
can also decrease. The cost of installing an ATI system in a long-haul truck is generally recouped in just over 2 years through fuel
and maintenance cost savings.
There have been no scientific studies to document fuel savings obtained through the use of nitrogen inflation, but anecdotal reports
indicate some fleets are seeing benefits from this approach. One large national fleet reported to a panel of the National Academy
of Sciences that it observed a 1 to 1.5 percent reduction in fuel use after using a nitrogen inflation system. Additionally, nitrogen
inflation systems typically remove oxygen and water from the inflation gas; both oxygen and water can contribute to tire aging.
NEXT STEPS
1 Trucking compa-
nies can contact
tire manufactur-
ers or their state or
national trucking
associations for more
information about
the benefits of keep-
ing tires properly
inflated.
2 Fleet operation
managers can
consider installing
automatic tire pres-
sure inflation systems
on drive and trailer
tires to help maintain
proper tire inflation
pressure while trucks
are on the road.
3Interested fleets
can check with
equipment manufac-
turers and truck and
tire dealers for more
information on ATI,
nitrogen fill or other
technologies devel-
oped to enhance tire
maintenance and
ensure proper tire
inflation pressure.
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