§571.109 Standard No. 109--New pneumatic and certain specialty tires.
S1. Scope. This standard specifies tire dimensions and laboratory test requirements for bead unseating resistance, strength, endurance, and high speed performance; defines tire load ratings; and specifies labeling requirements for passenger car tires.
S2 Application This standard applies to new pneumatic radial tires for use on passenger cars manufactured before 1975, new pneumatic bias ply tires, T-type spare tires, ST, FI, and 8-12 rim diameter and below tires for use on passenger cars manufactured after 1948. However, it does not apply to any tire that has been so altered so as to render impossible its use, or its repair for use, as motor vehicle equipment.
S3. Definitions.
Bead means that part of the tire made of steel wires, wrapped or reinforced by ply cords, that is shaped to fit the rim.
Bead separation means a breakdown of bond between components in the bead area.
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 90º to the centerline of the tread.
Carcass means the tire structure, except tread and sidewall rubber.
Chunking means the breaking away of pieces of the tread or sidewall.
Cord means the strands forming the plies in the tire.
Cord separation means cords parting away from adjacent rubber compounds.
Cracking means any parting within the tread, sidewall, or innerliner of the tire extending to cord material.
CT means a pneumatic tire with an inverted flange tire and rim system in which the rim is designed with rim flanges pointed radially inward and the tire is designed to fit on the underside of the rim in a manner that encloses the rim flanges inside the air cavity of the 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.
Load rating means the maximum load a tire is rated to carry for a given inflation pressure.
Maximum permissible inflation pressure means the maximum cold inflation pressure to which a tire may be inflated.
Maximum load rating means the load rating at the maximum permissible inflation pressure for that tire.
Open splice means any parting at any junction of tread, sidewall, or innerliner that extends to cord material.
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.
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, which, 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 which extend to the beads are laid at substantially 90º to the centerline of the tread.
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 the bead.
Sidewall separation means the parting of the rubber compound from the cord material in the sidewall.
Test rim means, with reference to a tire to be tested, any rim that is listed as appropriate for use with that tire in accordance with S4.4. For purposes of this section and It shall incorporate a tread wear indicator that will provide a visual indication that the tire has worn to a tread depth of 1.6 mm (1/16 inch).
(e) It shall, before being subjected to either the endurance test procedure specified in S5.4 or the high speed performance procedure specified in S5.5, exhibit no visual evidence of tread, sidewall, ply, cord, innerliner, or bead separation, chunking, broken cords, cracking, or open splices.
(f) It shall meet the requirements of S4.2.2.5 and S4.2.2.6 when tested on a test wheel described in S5.4.2.1 either alone or simultaneously with up to 5 other tires.
S4.2.2 Test requirements.
S4.2.2.1 Test sample. For each test sample use:
(a) One tire for physical dimensions, resistance to bead unseating, and strength, in sequence;
(b) Another tire for tire endurance; and
(c) A third tire for high speed performance.
S4.2.2.2 Physical dimensions. The actual section width and overall width for each tire measured in accordance with S5.1, shall not exceed the section width specified in a submission made by an individual manufacturer, pursuant to S4.4.1(a) or in one of the publications described in S4.4.1(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%, or
(b) (For tires with a maximum permissible inflation pressure of 240, 280, 290, 300, 330, 350, or 390 kPa, or 60 psi) 7% or 10 mm (0.4 inches), whichever is larger.
S4.2.2.3 Tubeless tire resistance to bead unseating.
S4.2.2.3.1. When a tubeless tire that has a maximum inflation pressure other than 420 kPa (60 psi) is tested in accordance with S5.2, the applied force required to unseat the tire bead at the point of contact shall be not less than:
(a) 6,670 N (1,500 pounds) for tires with a designated section width of less than 160 mm (6 inches);
(b) 8,890 N (2,000 pounds) for tires with a designated section width of 160 mm (6 inches) or more but less than 205 mm (8 inches);
(c) 11,120 N (2,500 pounds) for tires with a designated section width of 205 mm (8 inches) or more, using the section width specified in a submission made by an individual manufacturer, pursuant to S4.4.1(a), or in one of the publications described in S4.4.1(b) for the applicable tire size designation and type.
S4.2.2.3.2 When a tire that has a maximum inflation pressure of 420 kPa (60 psi) is tested in accordance with S5.2, the applied force required to unseat the bead at the point of contact shall be not less than:
(a) 6,670 kPa (1,500 pounds) for tires with a maximum load rating of less than 399 kg (880 pounds);
(b) 8,8890 N (2,000 pounds) for tires with a maximum load rating of 399 kg (880 pounds) or more but less than 635 kg (1,400 pounds);
(c) 11,120 N (2,500 pounds) for tires with a maximum load rating of 635 kg
(1,400 pounds) or more, using the maximum load rating marked on the sidewall of
the tire. Labeling Requirements.
Except as provided in S4.3.1 and S4.3.2 of this standard, each tire, except
for those certified to comply with S5.5 of §571.139, shall have permanently
molded into or onto both sidewalls, in letters and numerals not less than 0.078
inches high, the information shown in paragraphs S4.3 (a) through (g) of this
standard. On at least one sidewall, the information shall be positioned in an
area between the maximum section width and bead of the tire, unless the maximum
section width of the tire falls between the bead and one-fourth of the distance
from the bead to the shoulder of the tire. For tires where the maximum section
width falls in that area, locate all required labeling between the bead and a
point one-half the distance from the bead to the shoulder of the tire. However,
in no case shall the information be positioned on the tire so that it is
obstructed by the flange or any rim designated for use with that tire in
Standards Nos. 109 and 110 (§571.109
and §571.110 of this part).
(a) One size designation, except that equivalent inch and metric size
designations may be used;
(b) Maximum permissible inflation pressure;
(c) Maximum load rating;
(d) The generic name of each cord material used in the plies (both sidewall
and tread area) of the tire;
(e) Actual number of plies in the sidewall, and the actual number of plies
in the tread area if different;
(f) The words “tubeless” or “tube type” as applicable; and
(g) The word “radial” if the tire is a radial ply tire.
S4.3.1 Each tire shall be labeled with the symbol DOT in the manner specified in part 574 of this chapter, which shall constitute a certification that the tire conforms to applicable Federal motor vehicle safety standards.
S4.3.2 Each tire shall be labeled with the name of the manufacturer, or brand name and number assigned to the manufacturer in the manner specified in part 574.
S4.3.3 [Reserved]
S4.3.4 If the maximum inflation pressure of a tire is 240, 280, 290, 300, 330, 340, 350, or 390 kPa, then:
(a) Each marking of that inflation pressure pursuant to S4.3(b) shall be followed in parenthesis by the equivalent inflation pressure in psi, rounded to the next higher whole number; and
(b) Each marking of the tire's maximum load rating pursuant to S4.3(c) in kilograms shall be followed in parenthesis by the equivalent load rating in pounds, rounded to the nearest whole number.
S4.3.5 If the
maximum inflation pressure of a tire is 420 kPa (60 psi),
the tire shall have permanently molded into or onto both sidewalls, in letters
and numerals not less than 12.7 mm (½ inch), the words "Inflate to 420 kPa
(60 psi)".
On both sidewalls, the words shall be positioned in an area between the tire
shoulder and the bead of the tire. However, in no case shall the words be
positioned on the tire so that they are obstructed by the flange of any rim designated
for use with that tire in this standard or in Standard No. 110 (§571.139 shall ensure that a
listing of the rims that may be used with each tire that he produces is
provided to the public. A listing compiled in accordance with paragraph (a) of
S4.4.1 of this standard need not include dimensional specifications or diagram
of a rim if the rim's dimensional specifications and diagram are contained in
each listing published in accordance with paragraph (b) of S4.4.1 of this
standard. The listing shall be in one of the following forms:
(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 the 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:
The Tire and Rim Association
The European
Deutsche Industrie
Norm
British Standards Institution
Scandinavian Tire and Rim Organization
The
S4.4.2 Information contained in any publication specified in S4.4.1(b)
of this standard which lists general categories of tires and rims by size
designation, type of construction and/or intended use, shall be considered to
be manufacturer's information pursuant to S4.4.1 of this standard for the
listed tires and rims, unless the publication itself or specific information
provided according to S4.4.1(a) of this standard indicates otherwise.
S5. Test procedures.
S5.1 Physical Dimensions. Determine tire physical dimensions under uniform ambient conditions as follows:
(a) Mount the tire on a test rim having the test rim width specified in a submission made by an individual manufacturer, pursuant to S4.4.1(a), or in one of the publications described in S4.4.1(b) for that tire size designation and inflate it to the applicable pressure specified in Table II.
(b) Condition it at ambient room temperature for at least 24 hours.
(c) Readjust pressure to that specified in (a).
(d) Caliper the section width and overall width at six points approximately equally spaced around the tire circumference.
(e) Record the average of these measurements as the section width and overall width, respectively.
(f) Determine tire outer diameter by measuring the maximum circumference of the tire and dividing this dimension by pi (3.14).
S5.2 Tubeless tire bead unseating resistance.
S5.2.1 Preparation of tire-wheel assembly.
S5.2.1.1 Wash the tire, dry it at the beads, and mount it without lubrication or adhesives on a clean, painted test rim.
S5.2.1.2 Inflate it to the applicable pressure specified in Table II at ambient room temperature.
S5.2.1.3 Mount the wheel and tire in a fixture shown in Figure 1, and force the bead unseating block shown in Figure 2 or Figure 2A against the tire sidewall as required by the geometry of the fixture. However, in testing a tire that has an inflation pressure of 60 psi, only use the bead unseating block described in Figure 2A.
S5.2.2 Test procedure.
S5.2.2.1 Apply a load through the block to the tire outer sidewall at the distance specified in Figure 1 for the applicable wheel size at a rate of 50 mm (2 inches) per minute, with the load arm substantially parallel to the tire and rim assembly at the time of engagement. Force a 19 mm (¾–inch) diameter cylindrical steel plunger with a hemispherical end perpendicularly into the tread rib as near to the centerline as possible, avoiding penetration into the tread groove, at the rate of 50 mm (2 inches) per minute. Compute the breaking energy for each test point by means of the two following formulas:
W = [(F X P)/2]X103 (joules)
Where
W = Energy, in joules;
F = Force,
P = Penetration, mm;
or
W = [(F X P)/2]
Where
W = Energy, inch–pounds;
F = Force, pounds; and
P = Penetration, inches. S5.4.1.2 Condition the tire assembly to 38±3 ºC (100±5 °F) for at least three hours. S5.4.2.1 Mount the tire and wheel assembly on a test axle and press it against a flat-faced steel test wheel 1708 mm (67.23 inches) in diameter and at least as wide as the section width of the tire to be tested or an approved equivalent test wheel, with the applicable test load specified in the table in S5.4.2.3 for the tire's size designation, type, and maximum permissible inflation pressure. During the test, the air surrounding the test area shall be 38±3 ºC 100±5 °F. Conduct the test at 80 kilometers per hour (km/h) 50 miles per hour) in accordance with the following schedule without pressure adjustment or other interruptions:
The loads for the following periods are the specified percentage of the
maximum load rating marked on the tire sidewall:
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Percent |
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4 hours |
85 |
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6 hours |
90 |
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24 hours |
100 Break in the tire by running it for 2 hours at 80 km/h (50 mph). S5.5.3 Allow to cool to 38±3 °C (100±5 °F) and readjust the inflation pressure to the applicable pressure specified in Table II. S5.5.4 Without readjusting inflation
pressure, test at 121 km/h (75 mph) for 30 minutes, 129 km/h (80 mph) for 30
minutes, and 137 km/h (85 mph) for 30 minutes.
FIGURE 2. DIAGRAM OF BEAD UNSEATING BLOCK ALL DIMENSIONS IN MILLIMETERS (mm) FIGURE 2A. DIAGRAM OF BEAD UNSEATING BLOCK ALL DIMENSIONS IN MILLIMETERS (mm) Appendix A—Federal Motor Vehicle
Safety Standard No. 109 The following tables list tire sizes and tire constructions with proper load and inflation values. The tables group tires of related constructions and load/inflation values. Persons requesting the addition of new tire sizes to the tables or the addition of tables for new tire constructions may, when the additions requested are compatible with existent groupings, or when adequate justification for new tables exists, submit five (5) copies of information and data supporting the request to the Vehicle Dynamics Division, Office of Crash Avoidance Standards, National Highway Traffic Safety Administration, 400 Seventh Street SW., Washington, DC 20590. The information should contain the following: 1. The tire size designation, and a statement either that the tire is an addition to a category of tires listed in the tables or that it is in a new category for which a table has not been developed. 2. The tire dimensions, including aspect ratio, size factor, section width, overall width, and test rim size. 3. The load–inflation schedule of the tire. 4. A statement as to whether the tire size designation and load inflation schedule has been coordinated with the Tire and Rim Association, the European Tyre and Rim Technical Organisation, the Japan Automobile Tire Manufacturers' Association, Inc., the Deutsche Industrie Norm, the British Standards Institution, the Scandinavian Tire and Rim Organization, and the Tyre and Rim Association of Australia. 5. Copies of test data sheets showing test conditions, results and
conclusions obtained for individual tests specified in
Cord Material Maximum permissible
inflation Cord Material 32 psi 36 psi 40 psi 240 kPa 280 kPa 300 kPa 340 kPa Rayon (in-lbs) 1,650 2,574 3,300 1,650 3,300 1,650 3,300 Rayon (joules) 186 291 373 186 373 186 373 Nylon or polyester (in-lbs) 2,600 3,900 5,200 2,600 5,200 2,600 5,200 Nylon or polyester (joules) 294 441 588 294 588 294 588 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
TABLE I–B—FOR BIAS PLY TIRES WITH
DESIGNATED SECTION WIDTH BELOW 152 mm (6 INCHES
|
Cord Material |
Maximum permissible inflation |
||||||
|
32 psi |
36 psi |
40 psi |
240 kPa |
280 kPa |
300 kPa |
340 kPa |
|
|
Rayon (in-lbs) |
1,000 |
1,875 |
2,500 |
1,000 |
2,500 |
1,000 |
2,500 |
|
Rayon (joules) |
113 |
212 |
282 |
113 |
282 |
113 |
282 |
|
Nylon or polyester (in-lbs) |
1,950 |
2,925 |
3,900 |
1,950 |
3,900 |
1,950 |
3,900 |
|
Nylon or polyester (joules) |
220 |
330 |
441 |
220 |
441 |
220 |
441 |
TABLE I–C—FOR RADIAL PLY TIRES
|
Size designation |
Maximum Permissible Inflation |
|||||||||||
|
Tires other than CT tires |
CT Tires |
|||||||||||
|
psi |
kPa |
kPa |
||||||||||
|
32 |
36 |
40 |
240 |
280 |
300 |
340 |
350 |
290 |
330 |
350 |
390 |
|
|
Below 160 mm (in-lbs) |
1,950 |
2,925 |
3,900 |
1,950 |
3,900 |
1,950 |
3,900 |
1,950 |
1,950 |
3,900 |
1,950 |
3,900 |
|
(joules) |
220 |
330 |
441 |
220 |
441 |
220 |
441 |
220 |
220 |
441 |
220 |
441 |
|
160 mm or above (in-lbs) |
2,600 |
3,900 |
5,200 |
2,600 |
5,200 |
2,600 |
5,200 |
2,600 |
2,600 |
5,200 |
2,600 |
5,200 |
|
(joules) |
294 |
441 |
588 |
294 |
588 |
294 |
588 |
294 |
294 |
588 |
294 |
588 |
TABLE I–D FOR TIRES WITH 420 kPa
(60 psi)
MAXIMUM PERMISSIBLE INFLATION PRESSURE AND MAXIMUM LOAD RATING BELOW 399 kg
(880 LB) AND ABOVE
|
Cord material |
Inch-pounds – joules (J) |
|
Rayon |
1,650 inch pounds – |
|
Nylon or polyester |
2,600 inch pounds - |
TABLE I–E—FOR TIRES WITH 420 kPa
(6O psi)
MAXIMUM PERMISSIBLE INFLATION PRESSURE AND MAXIMUM LOAD RATING BELOW 399 kg
(880 LB)
|
Cord material |
Inch-pounds – joules (J) |
|
Rayon |
1,000 inch pounds - |
|
Nylon or polyester |
1,950 inch pounds - |
[38 FR 30235,