050310020G

Bulletin No.:
Service Bulletin
Date:
05-03-10-020G
March, 2020
INFORMATION
Subject:
Use of Nitrogen Gas in Tires
Models:
2020 and Prior GM Passenger Cars and Trucks
Attention: This bulletin also applies to any of the above models that may be Export from North
America vehicles.
This bulletin has been revised to add the 2016-2020 Model Years. Please discard Corporate
Bulletin Number 05-03-10-020F.
GM's Position on the Use of Nitrogen
Gas in Tires
General Motors does not oppose the use of purified
nitrogen as an inflation gas for tires. We expect the
theoretical benefits to be reduced in practical use due
to the lack of an existing infrastructure to continuously
facilitate inflating tires with nearly pure nitrogen. Even
occasional inflation with compressed atmospheric air
will negate many of the theoretical benefits. Given
those theoretical benefits, practical limitations, and the
robust design of GM original equipment TPC tires, the
realized benefits to our customer of inflating their tires
with purified nitrogen are expected to be minimal.
GM’s Position on the Use of Green
Valve Stem Caps
Green valve stem caps should not be installed on
vehicles in dealer stock, and should only be installed at
point-of-sale if the owner of the vehicle approves/
requests that they be installed along with nitrogen.
Copyright 2020 General Motors LLC. All Rights Reserved.
Important: The use of non GM valve stem caps can
result in a loss of sealing at the cap. This may allow
contaminants/water into the valve stem. These
contaminants can damage/destroy the TPMS and such
damage caused by leakage of contaminants would not
be covered by the GM New Vehicle Warranty.
The Promise of Nitrogen: Under
Controlled Conditions
Recently, nitrogen gas (for use in inflating tires) has
become available to the general consumer through
some retailers. The use of nitrogen gas to inflate tires is
a technology used in automobile racing. The following
benefits under controlled conditions are attributed to
nitrogen gas and its unique properties:
• A reduction in the expected loss of Tire Pressure
over time.
• A reduction in the variance of Tire Pressures with
temperature changes due to reduction of water
vapor concentration.
• A reduction of long term rubber degradation due to
a decrease in oxygen concentrations.
Important: These are obtainable performance
improvements when relatively pure nitrogen gas is
used to inflate tires under controlled conditions.
Page 2
March, 2020
The Promise of Nitrogen: Real
World Use
Nitrogen inflation can provide some benefit by reducing
gas migration (pressure loss) at the molecular level
through the tire structure. NHTSA (National Highway
Traffic Safety Administration) has stated that the
inflation pressure loss of tires can be up to 5% a month.
Nitrogen molecules are larger than oxygen molecules
and, therefore, are less prone to “seeping” through the
tire casing. The actual obtainable benefits of nitrogen
vary, based on the physical construction and the
materials used in the manufacturing of the tire being
inflated.
Another potential benefit of nitrogen is the reduced
oxidation of tire components. Research has
demonstrated that oxygen consumed in the oxidation
process of the tire primarily comes from the inflation
media. Therefore, it is reasonable to assume that
oxidation of tire components can be reduced if the tire
is inflated with pure nitrogen. However, only very small
amounts of oxygen are required to begin the normal
oxidation process. Even slight contamination of the tire
inflation gas with compressed atmospheric air during
normal inflation pressure maintenance, may negate the
benefits of using nitrogen.
GM Tire Quality, Technology and Focus of
Importance
Since 1972, General Motors has designed tires under
the TPC (Tire Performance Criteria) specification
system, which includes specific requirements that
Bulletin No.: 05-03-10-020G
ensure robust tire performance under normal usage.
General Motors works with tire suppliers to design and
manufacture original equipment tires for GM vehicles.
The GM TPC addresses required performance with
respect to both inflation pressure retention, and
endurance properties for original equipment tires. The
inflation pressure retention requirements address
availability of oxygen and oxidation concerns, while
endurance requirements ensure the mechanical
structure of the tire has sufficient strength. This
combination has provided our customers with tires that
maintain their structural integrity throughout their useful
treadlife under normal operating conditions.
Regardless of the inflation media for tires (atmospheric
air or nitrogen), inflation pressure maintenance of tires
is critical for overall tire, and ultimately, vehicle
performance. Maintaining the correct inflation pressure
allows the tire to perform as intended by the vehicle
manufacturer in many areas, including comfort, fuel
economy, stopping distance, cornering, traction,
treadwear, and noise. Since the load carrying capability
of a tire is related to inflation pressure, proper inflation
pressure maintenance is necessary for the tire to
support the load imposed by the vehicle without
excessive structural degradation.
Important: Regardless of the inflation media for tires
(atmospheric air or nitrogen), inflation pressure
maintenance of tires is critical for overall tire, and
ultimately, vehicle performance.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these
technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper
service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a
job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your
vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the
information.
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