[Code of Federal Regulations]
[Title 49, Volume 6]
[Revised as of October 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 49CFR571.139]
[Page 501-507]
TITLE 49--TRANSPORTATION
OF TRANSPORTATION
PART 571_FEDERAL MOTOR VEHICLE SAFETY STANDARDS--Table of Contents
Subpart B_Federal Motor Vehicle Safety Standards
Sec. 571.139 Standard No. 139; New pneumatic radial tires for light vehicles.
S1. Scope and purpose. This standard specifies tire dimensions, test
requirements, labeling requirements, and defines tire load ratings.
S2 Application and Incorporation by Reference.
S2.1 Application. This standard applies to new pneumatic radial
tires for use on motor vehicles (other than motorcycles and low speed
vehicles) that have a gross vehicle weight rating (GVWR) of 10,000
pounds or less and that were manufactured after 1975. This standard does
not apply to special tires (ST) for trailers in highway service, tires
for use on farm implements (FI) in agricultural service with
intermittent highway use, tires with rim diameters of 8 inches and
below, or T-type temporary use spare tires with radial construction.
S2.2 Incorporation by reference. ASTM F-1805-00, Standard Test
Method for Single Wheel Driving Traction in a Straight Line on Snow- and
Ice-Covered Surfaces is incorporated by reference in S3 of this section.
The Director of the Federal Register has approved the incorporation by
reference of this material in accordance with 5 U.S.C. 552(a) and 1 CFR
Part 51. A copy of ASTM F-1805-00 may be obtained from the ASTM Web site
http://www.astm.org/ or by contacting ASTM, or by contacting ASTM, 100
Barr Harbor Drive, West Conshohocken, PA 19428-2959. A copy of ASTM F-
1805-00 may be obtained from the NHTSA docket at Docket No. 2005-23439,
or at the National Archives and Records Administration (NARA). For
information on the availability of this material at NARA, call 202-741-
6030, or go to: http://www.archives.gov/federal--register/code--of--
federal--regulations/ibr--locations.html.
S3 Definitions.
Bead means the part of the tire that is made of steel wires, wrapped
or reinforced by ply cords and that is shaped to fit the rim.
Bead separation means a breakdown of the bond between components in
the bead.
Bias ply tire means a pneumatic tire in which the ply cords that
extend to the beads are laid at alternate angles substantially less than
90 degrees to the centerline of the tread.
Carcass means the tire structure, except tread and sidewall rubber
which, when inflated, bears the load.
Chunking means the breaking away of pieces of the tread or sidewall.
[[Page 502]]
Cord means the strands forming the plies in the tire.
Cord separation means the parting of cords from adjacent rubber
compounds.
Cracking means any parting within the tread, sidewall, or inner
liner of the tire extending to cord material.
Extra load tire means a tire designed to operate at higher loads and
higher inflation pressure than the corresponding standard tire.
Groove means the space between two adjacent tread ribs.
Innerliner means the layer(s) forming the inside surface of a
tubeless tire that contains the inflating medium within the tire.
Innerliner separation means the parting of the innerliner from cord
material in the carcass.
Light truck (LT) tire means a tire designated by its manufacturer as
primarily intended for use on lightweight trucks or multipurpose
passenger vehicles.
Load rating means the maximum load that a tire is rated to carry for
a given inflation pressure.
Maximum load rating means the load rating for a tire at the maximum
permissible inflation pressure for that tire.
Maximum permissible inflation pressure means the maximum cold
inflation pressure to which a tire may be inflated.
Measuring rim means the rim on which a tire is fitted for physical
dimension requirements.
Open splice means any parting at any junction of tread, sidewall, or
innerliner that extends to cord material.
Outer diameter means the overall diameter of an inflated new tire.
Overall width means the linear distance between the exteriors of the
sidewalls of an inflated tire, including elevations due to labeling,
decorations, or protective bands or ribs.
Passenger car tire means a tire intended for use on passenger cars,
multipurpose passenger vehicles, and trucks, that have a gross vehicle
weight rating (GVWR) of 10,000 pounds or less.
Ply means a layer of rubber-coated parallel cords.
Ply separation means a parting of rubber compound between adjacent
plies.
Pneumatic tire means a mechanical device made of rubber, chemicals,
fabric and steel or other materials, that, when mounted on an automotive
wheel, provides the traction and contains the gas or fluid that sustains
the load.
Radial ply tire means a pneumatic tire in which the ply cords that
extend to the beads are laid at substantially 90 degrees to the
centerline of the tread.
Reinforced tire means a tire designed to operate at higher loads and
at higher inflation pressures than the corresponding standard tire.
Rim means a metal support for a tire or a tire and tube assembly
upon which the tire beads are seated.
Section width means the linear distance between the exteriors of the
sidewalls of an inflated tire, excluding elevations due to labeling,
decoration, or protective bands.
Sidewall means that portion of a tire between the tread and bead.
Sidewall separation means the parting of the rubber compound from
the cord material in the sidewall.
Test rim means the rim on which a tire is fitted for testing, and
may be any rim listed as appropriate for use with that tire.
Tread means that portion of a tire that comes into contact with the
road.
Tread rib means a tread section running circumferentially around a
tire.
Tread separation means pulling away of the tread from the tire
carcass.
Treadwear indicators (TWI) means the projections within the
principal grooves designed to give a visual indication of the degrees of
wear of the tread.
Wheel-holding fixture means the fixture used to hold the wheel and
tire assembly securely during testing.
S4. Tire and rim matching information.
S4.1. Each manufacturer of tires must ensure that a listing of the
rims that may be used with each tire that it produces is provided to the
public in accordance with S4.1.1 and S4.1.2.
S4.1.1 Each rim listing for a tire must include dimensional
specifications and a diagram of the rim and must be in one of the
following forms:
[[Page 503]]
(a) Listed by manufacturer name or brand name in a document
furnished to dealers of the manufacturer's tires, to any person upon
request, and in duplicate to: Docket Section, National Highway Traffic
Safety Administration, 400 Seventh Street, SW., Washington, DC 20590; or
(b) Contained in publications, current at the date of manufacture of
the tire or any later date, of at least one of the following
organizations:
(1) The Tire and Rim Association.
(2) The European Tyre and Rim Technical Organization.
(3) Japan Automobile Tire Manufacturers' Association, Inc.
(4) Tyre & Rim Association of Australia.
(5) Associacao Latino Americana de Pneus e Aros (Brazil).
(6) South African Bureau of Standards.
S4.1.2 A listing compiled in accordance with paragraph (a) of S4.1.1
need not include dimensional specifications or a diagram of a rim whose
dimensional specifications and diagram are contained in a listing
published in accordance with paragraph (b) of S4.1.1.
S4.2. Information contained in a publication specified in S4.1.1(b)
that lists general categories of tires and rims by size designation,
type of construction, and/or intended use, is considered to be
manufacturer's information required by S4.1 for the listed tires, unless
the publication itself or specific information provided according to
S4.1(a) indicates otherwise.
S5. General requirements
S5.1. Size and construction. Each tire shall fit each rim specified
for its size designation in accordance with S4.1.
S5.2. Performance requirements. Each tire shall conform to each of
the following:
(a) It shall meet the requirements specified in S6 for its tire size
designation, type, and maximum permissible inflation pressure.
(b) It shall meet each of the applicable requirements set forth in
paragraphs (c) and (d) of this S5.2, when mounted on a model rim
assembly corresponding to any rim designated by the tire manufacturer
for use with the tire in accordance with S4.
(c) Its maximum permissible inflation pressure shall be 240, 280,
300, 340, or 350 kPa.
(d) Its load rating shall be that specified either in a submission
made by an individual manufacturer, pursuant to S4, or in one of the
publications described in S4 for its size designation, type and each
appropriate inflation pressure. If the maximum load rating for a
particular tire size is shown in more than one of the publications
described in S4, each tire of that size designation shall have a maximum
load rating that is not less than the published maximum load rating, or
if there are differing maximum load ratings for the same tire size
designation, not less then the lowest published maximum load rating.
S5.3. Test sample. For the tests specified in S6, use:
(a) One tire for high speed;
(b) Another tire for endurance and low inflation pressure
performance; and
(c) A third tire for physical dimensions, resistance to bead
unseating, and strength, in sequence.
S5.4. Treadwear indicators. Except in the case of tires with a 12-
inch or smaller rim diameter, each tire shall have not less than six
treadwear indicators spaced approximately equally around the
circumference of the tire that enable a person inspecting the tire to
determine visually whether the tire has worn to a tread depth of one
sixteenth of an inch. Tires with 12-inch or smaller rim diameter shall
have not less than three such treadwear indicators.
S5.5 Tire markings. Except as specified in paragraphs (a) through
(i) of S5.5, each tire must be marked on each sidewall with the
information specified in S5.5(a) through (d) and on one sidewall with
the information specified in S5.5(e) through (i) according to the phase-
in schedule specified in S7 of this standard. The markings must be
placed between the maximum section width and the bead on at least one
sidewall, unless the maximum section width of the tire is located in an
area that is not more than one-fourth of the distance from the bead to
the shoulder of the tire. If the maximum section width falls within that
area, those markings
[[Page 504]]
must appear between the bead and a point one-half the distance from the
bead to the shoulder of the tire, on at least one sidewall. The markings
must be in letters and numerals not less than 0.078 inches high and
raised above or sunk below the tire surface not less than 0.015 inches.
S5.5.1 Tire identification number.
(a) Tires manufactured before September 1, 2009. Each tire must be
labeled with the tire identification number required by 49 CFR part 574
on a sidewall of the tire. Except for retreaded tires, either the tire
identification number or a partial tire identification number,
containing all characters in the tire identification number, except for
the date code and, at the discretion of the manufacturer, any optional
code, must be labeled on the other sidewall of the tire.
(b) Tires manufactured on or after September 1, 2009. Each tire must
be labeled with the tire identification number required by 49 CFR part
574 on the intended outboard sidewall of the tire. Except for retreaded
tires, either the tire identification number or a partial tire
identification number, containing all characters in the tire
identification number, except for the date code and, at the discretion
of the manufacturer, any optional code, must be labeled on the other
sidewall of the tire. Except for retreaded tires, if a tire does not
have an intended outboard sidewall, the tire must be labeled with the
tire identification number required by 49 CFR part 574 on one sidewall
and with either the tire identification number or a partial tire
identification number, containing all characters in the tire
identification number except for the date code and, at the discretion of
the manufacturer, any optional code, on the other sidewall.
S5.5.2 [Reserved]
S5.5.3 Each tire must be labeled with the name of the manufacturer,
or brand name and number assigned to the manufacturer in the manner
specified in 49 CFR part 574.
S5.5.4 For passenger car tires, if the maximum inflation pressure of
a tire is 240, 280, 300, 340, or 350 kPa, then:
(a) Each marking of that inflation pressure pursuant to S5.5(c) must
be followed in parenthesis by the equivalent psi, rounded to the next
higher whole number; and
(b) Each marking of the tire's maximum load rating pursuant to
S5.5(d) in kilograms must be followed in parenthesis by the equivalent
load rating in pounds, rounded to the nearest whole number.
S5.5.5 If the maximum inflation pressure of a tire is 420 kPa (60
psi), the tire must have permanently molded into or onto both sidewalls,
in letters and numerals not less than \1/2\ inch high, the words
``Inflate to 60 psi'' or ``Inflate to 420 kPa (60 psi).'' On both
sidewalls, the words must be positioned in an area between the tire
shoulder and the bead of the tire. However, the words must be also
positioned on the tire so that they are not obstructed by the flange of
any rim designated for use with that tire in this standard or in
Standard No. 110 (Sec. 571.110 of this part).
S5.5.6 For LT tires, the maximum permissible inflation pressure
shown must be the inflation pressure that corresponds to the maximum
load of the tire for the tire size as specified in one of the
publications described in S4.1.1.(b) of Sec. 571.139. At the
manufacturer's option, the shown inflation pressure may be as much as 10
psi (69 kPa) greater than the inflation pressure corresponding to the
specified maximum load.
S6. Test procedures, conditions and performance requirements. Each
tire shall meet all of the applicable requirements of this section when
tested according to the conditions and procedures set forth in S5 and
S6.1 through S6.7.
S6.1. Tire dimensions
S6.1.1 Test conditions and procedures.
S6.1.1.1 Tire Preparation.
S6.1.1.1.1 Mount the tire on the measuring rim specified by the tire
manufacturer or in one of the publications listed in S4.1.1
S6.1.1.1.2 For passenger car tires, inflate to the pressure
specified in the following table:
------------------------------------------------------------------------
Inflation pressure (kPa)
-------------------------------------------------------------------------
Standard Reinforced
------------------------------------------------------------------------
180..................................................... 220
------------------------------------------------------------------------
[[Page 505]]
S6.1.1.1.3 In the case of a LT tire, inflate it to the pressure at
maximum load as labeled on sidewall.
S6.1.1.1.4 Condition the assembly at an ambient room temperature of
20 [deg]C to 30 [deg]C for not less than 24 hours.
S6.1.1.1.5 Readjust the tire pressure to that specified in
S6.1.1.1.2.
S6.1.1.2 Test procedure.
S6.1.1.2.1 Measure the section width and overall width by caliper at
six points approximately equally spaced around the circumference of the
tire, avoiding measurement of the additional thickness of the special
protective ribs or bands. The average of the measurements so obtained
are taken as the section width and overall width, respectively.
S6.1.1.2.2 Determine the outer diameter by measuring the maximum
circumference of the tire and dividing the figure so obtained by Pi
(3.14).
S6.1.2 Performance Requirements. The actual section width and
overall width for each tire measured in accordance with S6.1.1.2 shall
not exceed the section width specified in a submission made by an
individual manufacturer, pursuant to S4.1.1(a) or in one of the
publications described in S4.1.1(b) for its size designation and type by
more than:
(a) (For tires with a maximum permissible inflation pressure of 32,
36, or 40 psi) 7 percent, or
(b) (For tires with a maximum permissible inflation pressure of 240,
280, 300, 340 or 350 kPa) 7 percent or 10 mm (0.4 inches), whichever is
larger.
S6.2 High Speed Performance
S6.2.1 Test conditions and procedures.
S6.2.1.1 Preparation of tire.
S6.2.1.1.1 Mount the tire on a test rim and inflate it to the
pressure specified for the tire in the following table:
------------------------------------------------------------------------
Test
Tire application pressure
(kPa)
------------------------------------------------------------------------
Passenger car tires
------------------------------------------------------------------------
Standard load.............................................. 220
Extra load................................................. 260
Load Range C............................................... 320
Load Range D............................................... 410
Load Range E............................................... 500
------------------------------------------------------------------------
Light truck tires with a nominal cross section 295 mm (11.5
inches)
------------------------------------------------------------------------
Load Range C............................................... 230
Load Range D............................................... 320
Load Range E............................................... 410
------------------------------------------------------------------------
S6.2.1.1.2 Condition the assembly at 32 to 38 [deg]C for not less
than 3 hours.
S6.2.1.1.3 Before or after mounting the assembly on a test axle,
readjust the tire pressure to that specified in S6.2.1.1.1.
S6.2.1.2 Test procedure.
S6.2.1.2.1 Press the assembly against the outer face of a test drum
with a diameter of 1.70 m 1%.
S6.2.1.2.2 Apply to the test axle a load equal to 85% of the tire's
maximum load carrying capacity.
S6.2.1.2.3 Break-in the tire by running it for 2 hours at 80 km/h.
S6.2.1.2.4 Allow tire to cool to 38[deg] C and readjust inflation
pressure to applicable pressure in 6.2.1.1.1 immediately before the
test.
S6.2.1.2.5 Throughout the test, the inflation pressure is not
corrected and the test load is maintained at the value applied in
S6.2.1.2.2.
S6.2.1.2.6 During the test, the ambient temperature, measured at a
distance of not less than 150 mm and not more than 1 m from the tire, is
maintained at not less than 32 [deg]C or more than 38 [deg]C.
S6.2.1.2.7 The test is conducted, continuously and uninterrupted,
for ninety minutes through three thirty-minute consecutive test stages
at the following speeds: 140, 150, and 160 km/h.
S6.2.1.2.8 Allow the tire to cool for between 15 minutes and 25
minutes. Measure its inflation pressure. Then, deflate the tire, remove
it from the test rim, and inspect it for the conditions specified in
S6.2.2(a).
S6.2.2 Performance requirements. When the tire is tested in
accordance with S6.2.1:
(a) There shall be no visual evidence of tread, sidewall, ply, cord,
innerliner, belt or bead separation, chunking, open splices, cracking,
or broken cords.
(b) The tire pressure, when measured at any time between 15 minutes
and 25 minutes after the end of the test, shall not be less than 95% of
the initial pressure specified in S6.2.1.1.1.
[[Page 506]]
S6.3 Tire Endurance
S6.3.1 Test conditions and procedures.
S6.3.1.1 Preparation of Tire.
S6.3.1.1.1 Mount the tire on a test rim and inflate it to the
pressure specified for the tire in the following table:
------------------------------------------------------------------------
Test
Tire application pressure
(kPa)
------------------------------------------------------------------------
Passenger car tires
------------------------------------------------------------------------
Standard load.............................................. 180
Extra load................................................. 220
Load Range C............................................... 260
Load Range D............................................... 340
Load Range E............................................... 410
------------------------------------------------------------------------
Light truck tires with a nominal cross section 295 mm (11.5
inches)
------------------------------------------------------------------------
Load Range C............................................... 190
Load Range D............................................... 260
Load Range E............................................... 340
------------------------------------------------------------------------
S6.3.1.1.2 Condition the assembly at 32 to 38 [deg]C for not less
than 3 hours.
S6.3.1.1.3 Readjust the pressure to the value specified in
S6.3.1.1.1 immediately before testing.
S6.3.1.2 Test Procedure.
S6.3.1.2.1 Mount the assembly on a test axle and press it against
the outer face of a smooth wheel having a diameter of 1.70 m 1%.
S6.3.1.2.2 During the test, the ambient temperature, at a distance
of not less than 150 mm and not more than 1 m from the tire, is
maintained at not less than 32 [deg]C or more than 38 [deg]C.
S6.3.1.2.3 Conduct the test, without interruptions, at the test
speed of not less than 120 km/h with loads and test periods not less
than those shown in the following table. For snow tires, conduct the
test at not less than 110 km/h.
------------------------------------------------------------------------
Load as a
percentage
Test period Duration of tire
(hours) maximum
load rating
------------------------------------------------------------------------
1............................................. 4 85
2............................................. 6 90
3............................................. 24 100
------------------------------------------------------------------------
S6.3.1.2.4 Throughout the test, the inflation pressure is not
corrected and the test loads are maintained at the value corresponding
to each test period, as shown in the table in S6.3.1.2.3.
S6.3.1.2.5 Allow the tire to cool for between 15 minutes and 25
minutes after running the tire for the time specified in the table in
S6.3.1.2.3, measure its inflation pressure. Inspect the tire externally
on the test rim for the conditions specified in S6.3.2(a).
S6.3.2 Performance requirements. When the tire is tested in
accordance with S6.3.1:
(a) There shall be no visual evidence of tread, sidewall, ply, cord,
belt or bead separation, chunking, open splices, cracking or broken
cords.
(b) The tire pressure, when measured at any time between 15 minutes
and 25 minutes after the end of the test, shall not be less than 95% of
the initial pressure specified in S6.3.1.1.1.
S6.4 Low Inflation Pressure Performance
S6.4.1 Test conditions and procedures.
S6.4.1.1 Preparation of tire.
S6.4.1.1.1 This test is conducted following completion of the tire
endurance test using the same tire and rim assembly tested in accordance
with S6.3 with the tire deflated to the following appropriate pressure:
------------------------------------------------------------------------
Test
Tire application pressure
(kPa)
------------------------------------------------------------------------
Passenger car tires
------------------------------------------------------------------------
Standard load.............................................. 140
Extra load................................................. 160
Load Range C............................................... 200
Load Range D............................................... 260
Load Range E............................................... 320
------------------------------------------------------------------------
Light truck tires with a nominal cross section 295 mm (11.5
inches)
------------------------------------------------------------------------
Load Range C............................................... 150
Load Range D............................................... 200
Load Range E............................................... 260
------------------------------------------------------------------------
S6.4.1.1.2 After the tire is deflated to the appropriate test
pressure in S6.4.1.1.1 at the completion of the endurance test,
condition the assembly at 32 to 38 [deg]C for not less than 2 hours.
S6.4.1.1.3 Before or after mounting the assembly on a test axle,
readjust the tire pressure to that specified in S6.4.1.1.1.
S6.4.1.2 Test procedure.
S6.4.1.2.1 The test is conducted for ninety minutes at the end of
the test specified in S6.3, continuous and uninterrupted, at a speed of
120 km/h (75 mph). For snow tires, conduct the test at not less than 110
km/h.
[[Page 507]]
S6.4.1.2.2 Press the assembly against the outer face of a test drum
with a diameter of 1.70 m + 1%.
S6.4.1.2.3 Apply to the test axle a load equal to 100% of the tire's
maximum load carrying capacity.
S6.4.1.2.4 Throughout the test, the inflation pressure is not
corrected and the test load is maintained at the initial level.
S6.4.1.2.5 During the test, the ambient temperature, at a distance
of not less than 150 mm and not more than 1 m from the tire, is
maintained at not less than 32 [deg]C or more than 38 [deg]C.
S6.4.1.2.6 Allow the tire to cool for between 15 minutes and 25
minutes. Measure its inflation pressure. Then, deflate the tire, remove
it from the test rim, and inspect it for the conditions specified in
S6.4.2(a).
S6.4.2 Performance requirements. When the tire is tested in
accordance with S6.4.1:
(a) There shall be no visual evidence of tread, sidewall, ply, cord,
innerliner, belt or bead separation, chunking, open splices, cracking,
or broken cords, and
(b) The tire pressure, when measured at any time between 15 minutes
and 25 minutes after the end of the test, shall not be less than 95% of
the initial pressure specified in S6.4.1.1.1.
S6.5 Tire strength.
S6.5.1 Tire strength for passenger car tires. Each tire shall comply
with the requirements of S5.3 of Sec. 571.109.
S6.5.2 Tire strength for LT tires. Each tire shall comply with the
requirements of S7.3 of Sec. 571.119.
S6.6 Tubeless tire bead unseating resistance. Each tire shall comply
with the requirements of S5.2 of Sec. 571.109. For light truck tires,
the maximum permissible inflation pressure to be used for the bead
unseating test is as follows:
Load Range C............................... 260 kPa.
Load Range D............................... 340 kPa.
Load Range E............................... 410 kPa.
For light truck tires with a nominal cross section greater than 295
mm (11.5 inches), the maximum permissible inflation pressure to be used
for the bead unseating test is as follows:
Load Range C............................... 190 kPa.
Load Range D............................... 260 kPa.
Load Range E............................... 340 kPa.
S7. Phase-in schedule for tire markings.
S7.1 Tires manufactured on or after September 1, 2005 and before
September 1, 2006. For tires manufactured on or after September 1, 2005
and before September 1, 2006, the number of tires complying with S4,
S5.5, S5.5.1, S5.5.2, S5.5.3, S5.5.4, S5.5.5, and S5.5.6 of this
standard must be equal to not less than 40% of the manufacturer's
production during that period.
S7.2 Tires manufactured on or after September 1, 2006 and before
September 1, 2007. For tires manufactured on or after September 1, 2006
and before September 1, 2007, the number of tires complying with S4,
S5.5, S5.5.1, S5.5.2, S5.5.3, S5.5.4, S5.5.5, and S5.5.6 of this
standard must be equal to not less than 70% of the manufacturer's
production during that period.
S7.3 Tires manufactured on or after September 1, 2007. Each tire
must comply with S4, S5.5, S5.5.1, S5.5.2, S5.5.3, S5.5.4, S5.5.5, and
S5.5.6 of this standard.
[67 FR 69627, Nov. 18, 2002, as amended at 68 FR 38150, June 26, 2003;
69 FR 31319, June 3, 2004; 71 FR 886, Jan. 6, 2006; 72 FR 49211, Aug.
28, 2007]