The following words and terms, when used in this chapter, have the following meanings, unless the context clearly indicates otherwise:

   Bead—That part of the tire made of steel wires, wrapped or reinforced by ply cords, that is shaped to fit the rim.

   Bead separation—A breakdown of bond between components in the bead area.

   Bias ply tire—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—The tire structure, except tread and sidewall rubber.

   Chunking—The breaking away of pieces of the tread or sidewall.

   Cord—The strands forming the plies in the tire.

   Cord separation—Cords parting away from adjacent rubber compounds.

   Cracking—Any parting within the tread, sidewall or innerliner of the tire extending to cord material.

   Groove—The space between two adjacent tread ribs.

   Innerliner—The layers forming the inside surface of a tubeless tire that contains the inflating medium within the tire.

   Innerliner separation—The parting of the innerliner from cord material in the carcass.

   Load rating—The maximum load a tire is rated to carry for a given inflation pressure.

   Maximum load rating—The load rating at the maximum permissible inflation pressure for that tire.

   Maximum permissible inflation pressure—The maximum cold inflation pressure to which a tire may be inflated.

   Open splice—Any parting at any junction of tread, sidewall or innerliner that extends to cord material.

   Overall width—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—A layer of rubber-coated parallel cords.

   Ply separation—A parting of rubber compound between adjacent plies.

   Pneumatic tire—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—A pneumatic tire in which the ply cords which extend to the beads are laid at substantially 90° to the centerline of the tread.

   Rim—A metal support for a tire or a tire and tube assembly upon which the tire beads are seated.

   Section width—The linear distance between the exteriors of the sidewalls of an inflated tire, excluding elevations due to labeling, decoration, or protective bands.

   Sidewall—That portion of a tire between the tread and the bead.

   Sidewall separation—The parting of the rubber compound from the cord material in the sidewall.

   Size factor—The sum of the section width and the outer diameter of a tire determined on the test rim.

   Test rim—With reference to a tire to be tested, any rim that is listed as appropriate for use with that tire in accordance with §  159.4(d) (relating to requirements). For purposes of this chapter and section 571.110, each rim listing shall include dimensional specifications and a diagram of the rim.

   Tread—That portion of a tire that comes into contact with the road.

   Tread rib—A tread section running circumferentially around a tire.

   Tread separation—Pulling away of the tread from the tire carcass.

 (a)  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 §  159.3 (relating to definitions).

 (b)  Performance requirements. Performance requirements shall be as follows:

   (1)  General. Each tire shall conform to each of the following:

     (i)   It shall meet the requirements specified in paragraph (2) for its tire size designation, type and maximum permissible inflation pressure.

     (ii)   Its maximum permissible inflation pressure shall be either 32, 36, 40, or 60 p.s.i., or 240, 280 or 300 KPa.

     (iii)   Its load rating shall be that specified in Table I of Appendix A of this chapter for its size designation, type and each appropriate inflation pressure.

     (iv)   If manufactured on or after August 1, 1968, it shall incorporate a tread wear indicator that will provide a visual indication that the tire has worn to a tread depth of 1/16 inch.

     (v)   It shall, before being subjected to either the endurance test procedure specified in §  159.5(d) (relating to test procedures) or the high speed performance procedure specified in §  159.5(e), exhibit no visual evidence of tread, sidewall, ply, cord, innerliner, or bead separation, chunking, broken cords, cracking or open splices.

     (vi)   It shall meet the requirements of paragraph (2)(v) and (2)(vi) when tested on a test wheel described in §  159.5(d)(2)(i) (relating to test procedures), either alone or simultaneously with up to five other tires.

   (2)  Test requirements. Test requirements shall be as follows:

     (i)   Test sample. For each test sample the following shall be used:

       (A)   One tire for physical dimensions, resistance to bead unseating, and strength, in sequence.

       (B)   Another tire for tire endurance.

       (C)   A third tire for high speed performance.

     (ii)   Physical dimensions. Each tire, when measured in accordance with §  159.5(a) shall conform with each of the following:

       (A)   Its actual section width and overall width shall not exceed by more than 7.0% the section width specified in Table I of Appendix A for its size designation and type.

       (B)   Its size factor shall be at least as large as that specified in Table I of Appendix A for its size designation and type.

     (iii)   Tubeless tire resistance to bead unseating. When tested in accordance with §  159.5(b), the applied force required to unseat the tire bead at the point of contact is less than:

       (A)   1,500 pounds for tires with a designated section width of less than 6 inches.

       (B)   2,000 pounds for tires with a designated section width of 6 inches or more but less than 8 inches.

       (C)   2,500 pounds for tires with a designated section width of 8 inches or more, using the section width specified in Table I of Appendix A for the applicable tire size designation and type.

     (iv)   Tire strength. Each tire shall meet the requirements for minimum breaking energy specified in Table II of Appendix A when tested in accordance with §  159.5(c).

     (v)   Tire endurance. When the tire has been subjected to the laboratory endurance test specified in §  159.5(d) 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:

       (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 §  159.5(d)(1)(i).

     (vi)   High speed performance. When the tire has been subjected to the laboratory high speed performance test specified in §  159.5(e), 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 subparagraph (v)(A) and (B).

 (c)  Labeling requirements. Labeling requirements shall be as follows:

   (1)  Except as provided in paragraphs (2) and (3), each tire shall have permanently molded into or onto both sidewalls, in letters and numerals not less than 0.078 inches high, the information shown in subparagraphs (i) through (vii). On at least one sidewall, the information shall be positioned in an area between the maximum section width and bead of the tire. However, in no case shall the information be positioned on the tire so that it is obstructed by the flange of any rim designed for use with that tire under the provisions of this chapter and Standard No. 571.110.

     (i)   One size designation, except that equivalent inch and metric size designations may be used.

     (ii)   Maximum permissible inflation pressure.

     (iii)   Maximum load rating.

     (iv)   The generic name of each cord material used in the plies, both sidewall and tread area, of the tire.

     (v)   Actual number of plies in the sidewall, and the actual number of plies in the tread area, if different.

     (vi)   The words ‘‘tubeless’’ or ‘‘tube type’’ as applicable.

     (vii)   The word ‘‘radial’’ if the tire is a radial ply tire.

   (2)  Each tire shall be labeled with the symbol ‘‘DOT’’ in the manner specified in 49 CFR Part 574, which shall constitute a certification that the tire conforms to applicable Federal motor vehicle safety standards.

   (3)  Each tire shall be labeled with the name of the manufacturer, or brand name and number assigned to manufacturer in the manner specified in 49 CFR Part 574.

   (4)  Each tire manufactured between March 1, 1971, and May 22, 1971, shall either:

     (i)   Comply with section 4.3(d)(2) and 4.3(i), as effective until May 22, 1971.

     (ii)   Be labeled with the tire identification number required by 49 CFR 574.5 and comply with paragraphs (2) and (3) as effective on and after May 22, 1971.

 (d)  Tire and rim matching information. Matching information requirements shall be as follows:

   (1)  Each manufacturer of tires 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 subparagraph (i) need not include dimensional specifications or diagram of a rim if the dimensional specifications and diagram of the rim are contained in each listing published in accordance with subparagraph (ii). The listing shall be in one of the following forms:

     (i)   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: Tire Division, National Highway Traffic Safety Administration, 400 Seventh Street S.W., Washington D.C. 20590.

     (ii)   Contained in publications current at the date of manufacture of the tire or any later date of at least one of the following organizations:

       (A)   The Tire and Rim Association.

       (B)   The European Tyre and Rim Technical Organisation.

       (C)   Japanese Industrial Standards.

       (D)   Deutsche Industrie Norm.

       (E)   The Society of Motor Manufacturers and Traders, Ltd.

       (F)   British Standards Institution.

       (G)   Scandinavian Tire and Rim Organisation.

   (2)  Information contained in any publication specified in paragraph (1)(ii) of this subsection which lists general categories of tires and rims by size designation, type of construction or intended use, shall be considered to be information of the manufacturer under paragraph (1) for the listed tires and rims, unless the publication itself or specific information provided according to paragraph (1)(i) indicates otherwise.

   The provisions of this §  159.4 amended January 26, 1979, effective January 27, 1979, 9 Pa.B. 346.

 (a)  Physical dimensions. Tire physical dimensions shall be determined under uniform ambient conditions as follows:

   (1)  Mount the tire on a test rim having the test rim width specified in Appendix A of this chapter for that tire size designation and inflate it to the applicable pressure specified in Table III of Appendix A.

   (2)  Condition it at ambient room temperature for at least 24 hours.

   (3)  Readjust pressure to that specified in paragraph (1).

   (4)  Caliper the section width and overall width at six points approximately equally spaced around the tire circumference.

   (5)  Record the average of these measurements as the section width and overall width, respectively.

   (6)  Determine tire outer diameter by measuring the maximum circumference of the tire and dividing this dimension by pi (3.14).

 (b)  Tubeless tire bead unseating resistance. Bead unseating resistance shall be tested as follows:

   (1)  Preparation of tire-wheel assembly. The tire-wheel assembly shall be prepared as follows:

     (i)   Wash the tire, dry it at the beads, and mount it without lubrication or adhesives on a clean, painted test rim.

     (ii)   Inflate it to the applicable pressure specified in Table III of Appendix A of this chapter at ambient room temperature.

     (iii)   Mount the wheel and tire in the fixture shown in Figure 1 of this section, and force the standard block shown in Figure 2 of this section, against the tire sidewall as required by the geometry of the fixture.

   Bead Unsealing Fixture Dimensions in InchesDiagram of Bead Unsealing Block Dimensions in Inches

Figure 1

Figure 2

   (2)  Test procedure. The test procedure shall be as follows:

     (i)   Apply a load through the block to the tire outer sidewall at the distance specified in Figure 1 of this section for the applicable wheel size at a rate of two inches per minute, with the load arm substantially parallel to the tire and rim assembly at the time of engagement.

     (ii)   Increase the load until the bead unseats or the applicable value specified in §  159.4(b)(2)(iii) (relating to requirements) is reached.

     (iii)   Repeat the test at least four places equally spaced around the tire circumference.

 (c)  Tire strength. Tire strength shall be tested as follows:

   (1)  Preparation of tire. The tire shall be prepared as follows:

     (i)   mount the tire on a test rim and inflate it to the applicable pressure specified in Table III of Appendix A of this chapter;

     (ii)   condition it at room temperature for at least three hours; and

     (iii)   readjust its pressure to that specified in subparagraph (i).

   (2)  Test procedure. The test procedure shall be as follows:

     (i)   Force a 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 two inches per minute.

     (ii)   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 subparagraph (iii).

     (iii)   Compute the breaking energy for each test point by means of the following formula:
F x P
W =
2

       W =Energy, inch-pounds;

       F =Force, pounds; and

       P =Penetration, inches.

     (iv)   Determine the breaking energy value for the tire by computing the average of the five values obtained in accordance with subparagraph (iii) of this paragraph.

 (d)  Tire endurance. Endurance shall be tested as follows:

   (1)  Preparation of tire. The tire shall be prepared as follows:

     (i)   Mount a new tire on a test rim and inflate it to the applicable pressure specified in Table III of Appendix A.

     (ii)   Condition the tire assembly to 100°F plus or minus 5°F for at least three hours.

     (iii)   Readjust tire pressure to that specified in subparagraph (i) immediately before testing.

   (2)  Test procedure. The test procedure shall be as follows:

     (i)   Mount the tire and wheel assembly on a test axle and press it against a flat-faced steel test wheel 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 Table I of Appendix A for the size designation, type, and maximum permissible inflation pressure of the tire.

     (ii)   During the test, the air surrounding the test area shall be 100°F plus or minus 5°F.

     (iii)   Conduct the test at 50 miles per hour in accordance with the following schedule without pressure adjustment or other interruptions:

     (iv)   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 §  159.4(b)(2)(v)(A) (relating to requirements).

 (e)  High speed performance. High speed performance shall be tested as follows:

   (1)  After preparing the tire in accordance with subsection (d)(1), mount the tire and wheel assembly in accordance with subsection (d)(2)(i) and press it against the test wheel with the load specified in Table I of Appendix A for the size designation of the tire and the applicable pressure specified in Column B of the following table:

   (2)  Break in the tire by running it for two hours at 50 miles per hour.

   (3)  Allow to cool to 100°F plus or minus 5°F and readjust the inflation pressure to the applicable pressure specified in Table III of Appendix A of this chapter.

   (4)  Without readjusting inflation pressure, test at 75 miles per hour for 30 minutes, 80 miles per hour for 30 minutes, and 85 miles per hour for 30 minutes.

   (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 §  159.4(b)(2)(v)(A).

   The provisions of this §  159.5 amended January 26, 1979, effective January 27, 1979, 9 Pa.B. 346.

 No tire of a type and size designation specified in Table I of Appendix A 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 in interstate commerce, or imported into the United States, for any purpose.

APPENDIX A

 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 copies of information and data supporting the request to the Secretary of Transportation, Attention: Motor Vehicle Programs, National Highway Traffic Safety Administration, U.S. Department of Transportation, Washington, D.C. 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 society of Manufacturers and Traders Limited, the Japan Automobile Tire Manufacturers Association, the Deutsche Industrie Norm and the Scandinavian Tire and Rim Organisation.

   (5)  Copies of test data sheets showing test conditions, results and conclusions obtained for individual tests specified in this chapter.

   (6)  Justification for the additional tire sizes.

   TIRE LOAD RATINGS, TEST RIMS, MINIMUM SIZE FACTORS, AND SECTION WIDTHS FOR CONVENTIONAL AND LOW SECTION HEIGHT BIAS PLY TIRES

    ¹ The letters “H”, “S” or “V” may be included in any specified tire size designation adjacent to or in place of the "dash".

    ² Actual section width and overall width shall not exceed the specified section width by more than 7 percent.

   TIRE LOAD RATINGS, TEST RIMS, MINIMUM SIZE FACTORS, AND SECTION WIDTHS FOR “70 SERIES” BIAS PLY TIRES

    ¹ The letters “H”, “S” or “V” may be included in any specified tire size designation adjacent to or in place of the “dash”.

    ² Actual section width and overall width shall not exceed the specified section width by more than 7 percent.

   TIRE LOAD RATINGS, TEST RIMS, MINIMUM SIZE FACTORS, AND SECTION WIDTHS FOR BIAS PLY TIRES

    ¹ The letters “H”, “S” or “V” may be included in any specified tire size designation adjacent to or in place of the “dash”.

    ² Actual section width and overall width shall not exceed the specified section width by more than 7 percent.

   TIRE LOAD RATINGS, TEST RIMS, MINIMUM SIZE FACTORS, AND SECTION WIDTHS FOR DASH(-) RADIAL PLY TIRES

    ¹ The letters “H”, “S” or “V” may be included in any specified tire size designation adjacent to or in place of the “dash”.

    ² Actual section width and overall width shall not exceed the specified section width by more than 7 percent.

   TIRE LOAD RATINGS, TEST RIMS, MINIMUM SIZE FACTORS, AND SECTION WIDTHS FOR “77 SERIES” BIAS PLY TIRES

    ¹ The letters “H”, “S” or “V” may be included in any specified tire size designation adjacent to or in place of the “dash”.

    ² Actual section width and overall width shall not exceed the specified section width by more than 7 percent.

   TIRE LOAD RATINGS, TEST RIMS, MINIMUM SIZE FACTORS, AND SECTION WIDTHS FOR TYPE “R” RADIAL PLY TIRES

    ¹ The letters “H”, “S” or “V” may be included in any specified tire size designation adjacent to the “R”.

    ² Actual section width and overall width shall not exceed the specified section width by more than 7 percent.

   TIRE LOAD RATINGS, TEST RIMS, MINIMUM SIZE FACTORS, AND SECTION WIDTHS FOR “70 SERIES” RADIAL PLY TIRES

    ¹ The letters “HR”, “SR” or “VR” may be included in any specified tire size designation adjacent to or in place of the “dash”.

    ² Actual section width and overall width shall not exceed the specified section width by more than 7 percent.

   TIRE LOAD RATINGS, TEST RIMS, MINIMUM SIZE FACTORS, AND SECTION WIDTHS FOR TYPE “R” RADIAL PLY TIRES

    ¹ The letters “H”, “S” or “V” may be included in any specified tire size designation adjacent to the “R”.

    ² Actual section width and overall width shall not exceed the specified section width by more than 7 percent.

   TIRE LOAD RATINGS, TEST RIMS, MINIMUM SIZE FACTORS, AND SECTION WIDTHS FOR “78 SERIES” BIAS PLY TIRES

    ¹ The letters “H”, “S” or “V” may be included in any specified tire size designation adjacent to or in place of the “dash”.

    ² Actual section width and overall width shall not exceed the specified section width by more than 7 percent.

   TIRE LOAD RATINGS, TEST RIMS, MINIMUM SIZE FACTORS, AND SECTION WIDTHS FOR “60 SERIES” BIAS PLY TIRES

    ¹ The letters “H”, “S” or “V” may be included in any specified tire size designation adjacent to or in place of the “dash”.

    ² Actual section width and overall width shall not exceed the specified section width by more than 7 percent.

   TIRE LOAD RATINGS, TEST RIMS, MINIMUM SIZE FACTORS, AND SECTION WIDTHS FOR “50 SERIES” CANTILEVERED SIDEWALL TIRES

    ¹ The letters “H”, “S” or “V” may be included in any specified tire size designation adjacent to or in place of the “dash”.

    ² Actual section width and overall width shall not exceed the specified section width by more than 7 percent.

   TIRE LOAD RATINGS, TEST RIMS, MINIMUM SIZE FACTORS, AND SECTION WIDTHS FOR “78 SERIES” RADIAL PLY TIRES

    ¹ The letters “H”, “S” or “V” may be included in any specified tire size designation adjacent to or in place of the “dash”.

    ² Actual section width and overall width shall not exceed the specified section width by more than 7 percent.

   TIRE LOAD RATINGS, TEST RIMS, MINIMUM SIZE FACTORS, AND SECTION WIDTHS FOR “70 SERIES” RADIAL PLY TIRES

    ¹ The letters “H”, “S” or “V” may be included in any specified tire size designation adjacent to the “R”.

    ² Actual section width and overall width shall not exceed the specified section width by more than 7 percent.

   TIRE LOAD RATINGS, TEST RIMS, MINIMUM SIZE FACTORS, AND SECTION WIDTHS FOR “LOW SECTION” TYPE “R” RADIAL PLY TIRES

    ¹ The letters “H”, “S” or “V” may be included in any specified tire size designation adjacent to the “R”.

    ² Actual section width and overall width shall not exceed the specified section width by more than 7 percent.

   TIRE LOAD RATINGS, TEST RIMS, MINIMUM SIZE FACTORS, AND SECTION WIDTHS FOR SERIES 45 CANTILEVERED SIDEWALL TIRES

    ¹ The letter “H”, “S” or “V” may be included in any specified tire size designation adjacent to or in place of the “dash”.

    ² Actual section width and overall width shall not exceed the specified section width by more than 7 percent.

   TIRE LOAD RATINGS, TEST RIMS, MINIMUM SIZE FACTORS, AND SECTION WIDTHS FOR “60 SERIES” RADIAL PLY TIRES

    ¹ The letters “H”, “S” or “V” may be included in any tire size designation adjacent to the “R”.

    ² Actual section width and overall width shall not exceed the specified section width by more than 7 percent.

   TIRE LOAD RATINGS, TEST RIMS, MINIMUM SIZE FACTORS, AND SECTION WIDTHS FOR “60 SERIES” RADIAL PLY TIRES

    ¹ The letters “H”, “S” or “V” may be included in any tire size designation adjacent to the “R”.

    ² Actual section width and overall width shall not exceed the specified section width by more than 7 percent.

   TIRE LOAD RATINGS, TEST RIMS, MINIMUM SIZE FACTORS, AND SECTION WIDTHS FOR “70 SERIES” RADIAL PLY TIRES

    ¹ The letter “H”, “S” or “V” may be included in any specified tire size designation adjacent to the “R”.

    ² Actual section width and overall width shall not exceed the specified section width by more than 7 percent.

   TIRE LOAD RATINGS, TEST RIMS, MINIMUM SIZE FACTORS, AND SECTION WIDTHS FOR “60 SERIES” CANTILEVERED TIRES

    ¹ The letters “H”, “S” or “V” may be included in any specified tire size designation adjacent to or in place of the “dash”.

    ² Actual section width and overall width shall not exceed the specified section width by more than 7 percent.

   TIRE LOAD RATINGS, TEST RIMS, MINIMUM SIZE FACTORS, AND SECTION WIDTHS FOR “50 SERIES” BIAS PLY TIRES