Source: https://www.govregs.com/regulations/title49_chapterV_part571_subpartB_section571.109
Timestamp: 2019-04-23 10:56:50+00:00

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49 CFR 571.109 - Standard No. 109; New pneumatic and certain specialty tires. § 571.109 - Standard No. 109; New pneumatic and certain specialty tires.
§ 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.
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 90° to the centerline of the tread.
Carcass means the tire structure, except tread and sidewall rubber.
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.
Load rating means the maximum load a tire is rated to carry for a given inflation pressure.
Maximum load rating means the load rating at the maximum permissible inflation pressure for that tire.
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 90° to the centerline of the tread.
Sidewall means that portion of a tire between the tread and the bead.
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 § 571.110, each rim listing shall include dimensional specifications and a diagram of the rim.
S4.1 Size and construction. Each tire shall be designed to fit each rim specified for its size designation in each reference cited in the definition of test rim in S3.
(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 ( 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.
(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 Tubeless tire resistance to bead unseating.
(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.
(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 Tire strength. Each tire shall meet the requirements for minimum breaking energy specified in Table 1 when tested in accordance with S5.3.
(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 High speed performance. When the tire has been subjected to the laboratory high speed performance test specified in S5.5, using a test rim that undergoes no permanent deformation and allows no loss of air through the portion that it comprises of the tire-rim pressure chamber, the tire shall meet the requirements set forth in S4.2.2.5 (a) and (b).
S4.3 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 (Sec. 571.109 and Sec. 571.110 of this part).
(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.
(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 ( 1/2 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 (§ 571.110 of this part).
S4.4 Tire and rim matching information.
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.
(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.
S5.2.2.1 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.
S5.3.1.1 Mount the tire on a test rim and inflate it to the applicable pressure specified in Table II.
S5.3.1.3 Readjust its pressure to that specified in S5.3.1.1.
S5.3.2.1 Force a 19 mm ( 3/4 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.
S5.3.2.2 Record the force and penetration at five test points equally spaced around the circumference of the tire. If the tire fails to break before the plunger is stopped by reaching the rim, record the force and penetration as the rim is reached and use these values in S5.3.2.3.
W=[(F × P)/2] × 10 × 3 (joules) Where W = Energy, in joules; F = Force, Newtons; and P = Penetration, mm; or W=[(F × P)/2] Where W = Energy, inch-pounds; F = Force, pounds; and P = Penetration, inches.
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.
S5.4.1.1 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.
S5.4.2.1 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).
S5.4.2.4 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).
S5.5.4 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. Nonconforming tires. No tire that is designed for use on passenger cars and manufactured on or after October 1, 1972, but does not conform to all the requirements of this standard, shall be sold, offered for sale, introduced or delivered for introduction into interstate commerce, or imported into the United States, for any purpose.
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.
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.
Rayon 1,650 inch pounds 186 joules (J).
Nylon or Polyester 2,600 inch pounds 294 joules (J).
Rayon 1,000 inch pounds 113 joules (J).
Nylon or Polyester 1,950 inch pounds 220 joules (J).
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.
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.
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.
[38 FR 30235, Nov. 1, 1973] Editorial Note:For Federal Register citations affecting § 571.109, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www.fdsys.gov.

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