S1.
S2.
S3.
S4.
S4.1
S4.2
S4.2.1
(a) It shall meet the requirements specified in S4.2.2 for its tire size designation, type, and maximum permissible inflation pressure.
(b) Its maximum permissible inflation pressure shall be either 32, 36, 40, or 60 psi, or 240, 280, 300, 340, or 350 kPa.
(c) Its load rating shall be that 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, 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 S4.4.1(b), 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 than the lowest published maximum load rating.
(d) 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 (
(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
S4.2.2.1
(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
(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, or 60 psi) 7 percent or 10 mm (0.4 inches), whichever is larger.
S4.2.2.3
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 N (1,500 pounds) for tires with a maximum load rating of less than 399 kg (880 pounds);
(b) 8,890 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.
S4.2.2.4
S4.2.2.5
(a) There shall be no visual evidence of tread, sidewall, ply, cord, innerliner, or bead separation, chunking, broken cords, cracking, or open splices.
(b) The tire pressure at the end of the test shall be not less than the initial pressures specified in S5.4.1.1.
S4.2.2.6
(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, 300, 340, or 350 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 (
S4.4
S4.4.1 Each manufacturer of tires not certified to comply with S4 of § 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
(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 (No: NHTSA–2009–0117), National Highway Traffic Safety Administration, West Building, 1200 New Jersey Ave SE., 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:
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.
S5.1
(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
S5.2.1
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
S5.2.2.1 Apply a load through the block to the tire's 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.
S5.2.2.2 Increase the load until the bead unseats or the applicable value specified in S4.2.2.3 is reached.
S5.2.2.3 Repeat the test at least four places equally spaced around the tire circumference.
S5.3
S5.3.1
S5.3.1.1 Mount the tire on a test rim and inflate it to the applicable pressure specified in Table II.
S5.3.1.2 Condition it at room temperature for at least 3 hours; and
S5.3.1.3 Readjust its pressure to that specified in S5.3.1.1.
S5.3.2
S5.3.2.1 Force a 19 mm (
S5.3.2.2 Record the force and penetration at five test points equally spaced around the circumference of the
S5.3.2.3 Compute the breaking energy for each test point by means of one of the two following formulas:
S5.3.2.4 Determine the breaking energy value for the tire by computing the average of the five values obtained in accordance with S5.3.2.3.
S5.4
S5.4.1
S5.4.1.1 Mount a new tire on a test rim and inflate it to the applicable pressure specified in Table II.
S5.4.1.2 Condition the tire assembly to 38° ±3 °C (100° ±5 °F) for at least three hours.
S5.4.1.3 Readjust tire pressure to that specified in S5.4.1.1 immediately before testing.
S5.4.2
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.
S5.4.2.2 During the test, the air surrounding the test area shall be 38° ±3 °C (100° ±5 °F).
S5.4.2.3 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:
S5.4.2.4 Immediately after running the tire the required time, measure its inflation pressure. Allow the tire to cool for one hour. Then deflate the tire, remove it from the test rim, and inspect it for the conditions specified in S4.2.2.5(a).
S5.5 High speed performance.
S5.5.1 After preparing the tire in accordance with S5.4.1, mount the tire and wheel assembly in accordance with S5.4.2.1, and press it against the test wheel with a load of 88 percent of the tire's maximum load rating as marked on the tire sidewall.
S5.5.2 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.
S5.5.5 Immediately after running the tire the required time, measure its inflation pressure. Allow the tire to cool for one hour. Then deflate the tire, remove it from the test rim, and inspect it for the conditions specified in S4.2.2.5(a).
S6.
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 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 deloped.
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 § 571.109.
6. Justification for the additional tire sizes.
Persons requesting the addition of new tire sizes not included in S4.4.1(b) organizations may, upon approval, 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, West Building, 1200 New Jersey Ave. SE., 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 Organization, the Japan Automobile Tyre Manufacturers Association, Inc., the Tyre and Rim Association of Australia, the Associacao Latino Americana de Pneus e Aros (Brazil), or the South African Bureau of Standards.
5. Copies of test data sheets showing test conditions, results and conclusions obtained for individual tests specified in § 571.109.
6. Justification for the additional tire sizes.
For