(a)
(b)
(c)
(2) “Limited production tire” means a tire meeting all of the following criteria, as applicable:
(i) The annual domestic production or importation into the United States by the tire's manufacturer of tires of the same design and size as the tire does not exceed 15,000 tires;
(ii) In the case of a tire marketed under a brand name, the annual domestic purchase or importation into the United States by a brand name owner of tires of the same design and size as the tire does not exceed 15,000 tires;
(iii) The tire's size was not listed as a vehicle manufacturer's recommended tire size designation for a new motor vehicle produced in or imported into the United States in quantities greater than 10,000 during the calendar year preceding the year of the tire's manufacture; and
(iv) The total annual domestic production or importation into the United States by the tire's manufacturer, and in the case of a tire marketed under a brand name, the total annual domestic purchase or purchase for importation into the United States by the tire's brand name owner, of tires meeting the criteria of paragraphs (c)(2) (i), (ii), and (iii) of this section, does not exceed 35,000 tires.
(d)
(A) Except for a tire of a new tire line, manufactured within the first six months of production of the tire line, each tire shall be graded with the words, letters, symbols, and figures specified in paragraph (d)(2) of this section, permanently molded into or onto the tire sidewall between the tire's maximum section width and shoulder in accordance with one of the methods described in Figure 1. For purposes of this paragraph, new tire line shall mean a group of tires differing substantially in construction, materials, or design from those previously sold by the manufacturer or brand name owner of the tires. As used in this paragraph, the term “construction” refers to the internal structure of the tire (e.g., cord angles, number and placement of breakers), “materials” refers to the substances used in manufacture of the tire (e.g., belt fiber, rubber compound), and “design” refers to properties or conditions imposed by the tire mold (e.g., aspect ratio, tread pattern).
(B) Each tire manufactured on and after the effective date of these amendments, other than a tire sold as original equipment on a new vehicle, shall have affixed to its tread surface so as not to be easily removable a label or labels containing its grades and other information in the form illustrated in Figure 2, Parts I and II. The treadwear grade attributed to the tire shall be either imprinted or indelibly stamped on the label containing the material in Part I of Figure 2, directly to the right of or below the word “TREADWEAR.”
(ii) In the case of the information required by § 575.6(c) to be furnished to prospective purchasers of tires, each tire manufacturer or brand name owner shall, as part of that information, list all possible grades for traction and temperature resistance, and restate verbatim the explanation for each performance area specified in Figure 2. The information need not be in the same format as in Figure 2. The information must indicate clearly and unambiguously the grade in each performance area for each tire of that manufacturer or brand name owner offered for sale at the particular location.
(iii) Each manufacturer of motor vehicles equipped with passenger car tires shall include in the owner's manual of each such vehicle a list of all possible grades for traction and temperature resistance and restate verbatim the explanation for each performance area specified in Figure 2, Part II. The information need not be in the exact format of Figure 2, Part II, but it must contain a statement referring the reader to the tire sidewall for the specific tire grades for the tires with which the vehicle is equipped, as follows:
Quality grades can be found where applicable on the tire sidewall between tread shoulder and maximum section width. For example:
(iv) In the case of information required in accordance with § 575.6(a) to be furnished to the first purchaser of a new motor vehicle, each manufacturer of motor vehicles shall, as part of the required information, list all possible grades for traction and temperature resistance and restate verbatim the explanation for each performance area specified in Figure 2 to this section. The information need not be in the format of Figure 2 to this section, but it must contain a statement referring the reader to the tire sidewall for the specific tire grades for the tires with which the vehicle is equipped.
(2)
(ii)
(A) The tire shall be graded C when the adjusted traction coefficient is either:
(
(
(B) The tire may be graded B only when its adjusted traction coefficient is both:
(
(
(C) The tire may be graded A only when its adjusted traction coefficient is both:
(
(
(D) The tire may be graded AA only when its adjusted traction coefficient is both:
(
(
(iii)
(A) The tire shall be graded C if it fails to complete the 500 rpm test stage specified in paragraph (g)(9) of this section.
(B) The tire may be graded B only if it successfully completes the 500 rpm test stage specified in paragraph (g)(9) of this section.
(C) The tire may be graded A only if it successfully completes the 575 rpm test stage specified in paragraph (g)(9) of this section.
(e)
(ii) Treadwear grades are evaluated by first measuring the performance of a candidate tire on the government test course, and then correcting the projected mileages obtained to account for environmental variations on the basis of the performance of the course monitoring tires run in the same convoy.
(iii) In convoy tests, each vehicle in the same convoy, except for the lead vehicle, is throughout the test within human eye range of the vehicle immediately ahead of it.
(iv) A test convoy consists of two or four passenger cars, light trucks, or MPVs, each with a GVWR of 10,000 pounds or less.
(v) On each convoy vehicle, all tires are mounted on identical rims of design or measuring rim width specified for tires of that size in accordance with
(2)
(ii) Inflate each candidate and each course monitoring tire to the applicable pressure specified in Table 1 of this section.
(iii) Load each vehicle so that the load on each course monitoring and candidate tire is 85 percent of the test load specified in § 575.104(h).
(iv) Adjust wheel alignment to the midpoint of the vehicle manufacturer's specifications, unless adjustment to the midpoint is not recommended by the manufacturer; in that case, adjust the alignment to the manufacturer's recommended setting. In all cases, the setting is within the tolerance specified by the manufacturer of the alignment machine.
(v) Subject candidate and course monitoring tires to “break-in” by running the tires in the convoy for two circuits of the test roadway (800 miles). At the end of the first circuit, rotate each vehicle's tires by moving each front tire to the same side of the rear axle and each rear tire to the opposite side of the front axle. Visually inspect each tire for any indication of abnormal wear, tread separation, bulging of the sidewall, or any sign of tire failure. Void the grading results from any tire with any of these anomalies, and replace the tire.
(vi) After break-in, allow the air pressure in the tires to fall to the applicable pressure specified in Table 1 of this section or for 2 hours, whichever occurs first. Measure, to the nearest 0.001 inch, the tread depth of each candidate and each course monitoring tire, avoiding treadwear indicators, at six equally spaced points in each groove. For each tire compute the average of the measurements. Do not measure those shoulder grooves which are not provided with treadwear indicators.
(vii) Adjust wheel alignment to the midpoint of the manufacturer's specifications, unless adjustment to the midpoint is not recommended by the manufacturer; in that case, adjust the alignment according to the manufacturer's recommended setting. In all cases, the setting is within the tolerance specified by the manufacturer of the alignment machine.
(viii) Drive the convoy on the test roadway for 16 circuits (approximately 6,400 miles).
(A) After every circuit (approximately 400 miles), rotate each vehicle's tires by moving each front tire to the same side of the rear axle and each rear tire to the opposite side of the front axle. Visually inspect each tire for treadwear anomalies.
(B) After every second circuit (approximately 800 miles), rotate the vehicles in the convoy by moving the last vehicle to the lead position. Do not rotate driver positions within the convoy. In four-car convoys, vehicle one shall become vehicle two, vehicle two shall become vehicle three, vehicle three shall become vehicle four, and vehicle four shall become vehicle one.
(C) After every second circuit (approximately 800 miles), if necessary, adjust wheel alignment to the midpoint of the vehicle manufacturer's specification, unless adjustment to the midpoint is not recommended by the manufacturer; in that case, adjust the alignment to the manufacturer's recommended setting. In all cases, the setting is within the tolerance specified by the manufacturer of the alignment machine.
(D) After every second circuit (approximately 800 miles), if determining the projected mileage by the 9-point method set forth in paragraph (e)(2)(ix)(A)(
(E) After every fourth circuit (approximately 1,600 miles), move the complete set of four tires to the following vehicle. Move the tires on the last vehicle to the lead vehicle. In moving the tires, rotate them as set forth in paragraph (e)(2)(viii)(A) of this section.
(F) At the end of the test, measure the tread depth of each tire pursuant
(ix)(A) Determine the projected mileage for each candidate tire either by the nine-point method of least squares set forth in paragraph (e)(2)(ix)(A)(
(
(
(
(B) Average the wear rates of the four course monitoring tires as determined in accordance with paragraph (e)(2)(ix)(A) of this section.
(C) Determine the course severity adjustment factor by dividing the base course wear rate for the course monitoring tires (
The ASTM F2493 standard reference test tire is the course monitoring tire (CMT). The base wear rate for the CMTs will be obtained by the Government by running the course monitoring tires for 16 circuits over the San Angelo, Texas, UTQGS test route 4 times per year, then using the average wear rate from the last 4 quarterly CMT tests for the base course wear rate calculation. Each new base course wear rate will be published in Docket No. NHTSA–2001–9395. The course monitoring tires used in a test convoy must be no more than one-year-old at the commencement of the test and must be used within four months after removal from storage.
(D) Determine the adjusted wear rate for each candidate tire by multiplying its wear rate determined in accordance with paragraph (e)(2)(ix)(A) of this section by the course severity adjustment factor determined in accordance with paragraph (e)(2)(ix)(C) of this section.
(E) Determine the projected mileage for each candidate tire by applying the appropriate formula set forth below:
(
(
(F) Compute the grade (P) of the of the NHTSA nominal treadwear value for each candidate tire by using the following formula:
Round off the percentage to the nearest lower 20-point increment.
(f)
(ii) The standard tire is the tire specified in ASTM E 501 (incorporated by reference,
(iii) The pavement surface is wetted in accordance with paragraph 4.7, “Pavement Wetting System,” of ASTM E 274 (incorporated by reference,
(iv) The test apparatus is a test trailer built in conformity with the specifications in paragraph 4, “Apparatus,” of ASTM E 274 (incorporated by reference,
(v) The test apparatus is calibrated in accordance with ASTM F 377 (incorporated by reference,
(vi) Consecutive tests on the same surface are conducted not less than 30 seconds apart.
(vii) A standard tire is discarded in accordance with ASTM E 501 (incorporated by reference,
(2)
(A) Condition the tires by running them for 200 miles on a pavement surface.
(B) Mount each tire on a rim of design or measuring rim width specified for tires of its size in accordance with 49 CFR 571.109, S4.4.1 (a) or (b), or a rim having a width within −0 to + 0.50 inches of the width listed. Then inflate the tire to 24 psi, or, in the case of a tire with inflation pressure measured in kilopascals, to 180 kPa.
(C) Statically balance each tire-rim combination.
(D) Allow each tire to cool to ambient temperature and readjust its inflation pressure to 24 psi, or, in the case of a tire with inflation pressure measured in kilopascals, to 180 kPa.
(ii) Mount the tires on the test apparatus described in paragraph (f)(1)(iv) of this section and load each tire to 1,085 pounds.
(iii) Tow the trailer on the asphalt test surface specified in paragraph (f)(1)(i) of this section at a speed of 40 mph, lock one trailer wheel, and record the locked-wheel traction coefficient on the tire associated with that wheel between 0.5 and 1.5 seconds after lockup.
(iv) Repeat the test on the concrete surface, locking the same wheel.
(v) Repeat the tests specified in paragraphs (f)(2) (iii) and (iv) of this section for a total of 10 measurements on each test surface.
(vi) Repeat the procedures specified in paragraphs (f)(2) (iii) through (v) of this section, locking the wheel associated with the other tire.
(vii) Average the 20 measurements taken on the asphalt surface to find the standard tire traction coefficient for the asphalt surface. Average the 20 measurements taken on the concrete surface to find the standard tire traction coefficient for the concrete surface. The standard tire traction coefficient so determined may be used in the computation of adjusted traction coefficients for more than one candidate tire.
(viii) Prepare two candidate tires of the same construction type, manufacturer, line, and size designation in accordance with paragraph (f)(2)(i) of this section, mount them on the test apparatus, and test one of them according to the procedures of paragraph (f)(2)(ii) through (v) of this section, except load each tire to 85% of the test load specified in § 575.104(h). For CT tires, the test inflation of candidate tires shall be 230 kPa. Candidate tire measurements may be taken either before or after the standard tire measurements used to compute the standard tire traction coefficient. Take all standard tire and candidate tire measurements used in computation of a candidate tire's adjusted traction coefficient within a single three hour period. Average the 10 measurements taken on the asphalt surface to find the candidate tire traction coefficient for the asphalt surface. Average the 10 measurements taken on the concrete surface to find the candidate tire traction coefficient for the concrete surface.
(ix) Compute a candidate tire's adjusted traction coefficient for asphalt (μ
(x) Compute a candidate tire's adjusted traction coefficient for concrete (μ
(g)
(2) Condition the tire-rim assembly to a temperature of 95 °F for at least 3 hours.
(3) Adjust the pressure again to the applicable pressure specified in Table 1 of this section.
(4) Mount the tire-rim assembly on an axle, and press the tire tread against the surface of a flat-faced steel test wheel that is 67.23 inches in diameter and at least as wide as the section width of the tire.
(5) During the test, including the pressure measurements specified in paragraphs (g) (1) and (3) of this section, maintain the temperature of the ambient air, as measured 12 inches from the edge of the rim flange at any point on the circumference on either side of the tire at 95 °F. Locate the temperature sensor so that its readings are not affected by heat radiation, drafts, variations in the temperature of the surrounding air, or guards or other devices.
(6) Press the tire against the test wheel with a load of 88 percent of the tire's maximum load rating as marked on the tire sidewall.
(7) Rotate the test wheel at 250 rpm for 2 hours.
(8) Remove the load, allow the tire to cool to 95 °F or for 2 hours, whichever occurs last, and readjust the inflation pressure to the applicable pressure specified in Table 1 of this section.
(9) Reapply the load and without interruption or readjustment of inflation pressure, rotate the test wheel at 375 rpm for 30 minutes, and then at successively higher rates in 25 rpm increments, each for 30 minutes, until the tire has run at 575 rpm for 30 minutes, or to failure, whichever occurs first.
(h)
(2) Determine the tire's maximum inflation pressure and maximum load rating both as specified on the tire's sidewall.
(3) Determine the appropriate multiplier corresponding to the tire's maximum inflation pressure, as set forth in Table 2.
(4) Multiply the tire's maximum load rating by the multiplier determined in paragraph (h)(3). This is the tire's calculated load.
(5) Round the product determined in paragraph (h)(4) (the calculated load) to the nearest multiple of ten pounds or, if metric units are used, 5 kilograms. For example, 903 pounds would be rounded to 900 and 533 kilograms would be rounded to 535. This figure is the test load.
(i)–(l) [Reserved]
(Part II) All Passenger Car Tires Must Conform to Federal Safety Requirements in Addition to These Grades
The treadwear grade is a comparative rating based on the wear rate of the tire when tested under controlled conditions on a specified government test course. For example, a tire graded 150 would wear one and one-half (1
The traction grades, from highest to lowest, are AA, A, B, and C. Those grades represent the tire's ability to stop on wet pavement as measured under controlled conditions on specified government test surfaces of asphalt and concrete. A tire marked C may have poor traction performance. Warning: The traction grade assigned to this tire is based on straight-ahead braking traction tests, and does not include acceleration, cornering, hydroplaning, or peak traction characteristics.
The temperature grades are A (the highest), B, and C, representing the tire's resistance to the generation of heat and its ability to dissipate heat when tested under controlled conditions on a specified indoor laboratory test wheel. Sustained high temperature can cause the material of the tire to degenerate and reduce tire life, and excessive temperature can lead to sudden tire failure. The grade C corresponds to a level of performance which all passenger car tires must meet under the Federal Motor Safety Standard No. 109. Grades B and A represent higher levels of performance on the laboratory test wheel than the minimum required by law. Warning: The temperature grade for this tire is established for a tire that is properly inflated and not overloaded. Excessive speed, underinflation, or excessive loading, either separately or in combination, can cause heat buildup and possible tire failure.
The first loop runs south 143 miles through the cities of Eldorado, Sonora, and Juno, Tex. to the Camp Hudson Historical Marker, and returns by the same route.
The second loop runs east over Farm and Ranch Roads (FM) and returns to its starting point.
The third loop runs northwest to Water Valley, northeast toward Robert Lee and returns via Texas 208 to the vicinity of Goodfellow AFB.
(A) Proceed south to Camp Hudson Historical Marker and onto the paved shoulder (7). Reverse route to junction of Loop Road 306 and FM 388 (2); or
(B) Proceed south to junction with Frank's Crossing. Reverse route at Frank's Crossing and proceed north on Texas 163 to junction with Highway 189; Reverse route at junction with Highway 189; proceed south on Texas 163 to junction with Frank's Crossing; reverse route at Frank's Crossing and proceed north to junction of Loop Road 306 and FM 388 (2).
2. When abreast of the STOP AHEAD sign, apply the brakes so that the vehicle decelerates smoothly to 20 mph when abreast of the direction sign.
3. Come to a complete stop at the STOP sign or behind any vehicle already stopped.
Two skid pads have been laid on an unused runway and taxi strip on Goodfellow AFB. Their location is shown in Figure 4.
The asphalt skid pad is 600 ft. × 60 ft. and is shown in black on the runway in Figure 4. The pad is approached from either end by a
The concrete pad is 600 ft. × 48 ft. and is on the taxi strip. The approaches to the concrete pad are of the same design as those for the asphalt pads.
A two lane asphalt road has been built to connect the runway and taxi strip. The road is parallel to the northeast-southwest runway at a distance of 100 ft. The curves have super-elevation to permit safe exit from the runway at operating speeds.
The method of least squares is a method of calculation by which it is possible to obtain a reliable estimate of a true physical relationship from a set of data which involve random error. The method may be used to establish a regression line that minimizes the sum of the squares of the deviations of the measured data points from the line. The regression line is consequently described as the line of “best fit” to the data points. It is described in terms of its slope and its “y” intercept.
The graph in Figure 5 depicts a regression line calculated using the least squares method from data collected from a hypothetical treadwear test of 6,400 miles, with tread depth measurements made at every 500 miles.
In this graph, x
The absolute value of the slope of the regression line is an expression of the mils of tread worn per 1,000 miles, and is calculated by the following formula:
The “
1.
2. Fee payments shall be by check, draft, money order, or Electronic Funds Transfer System made payable to the Treasurer of the United States.
3. The fee set forth in this Appendix continues in effect until adjusted by the Administrator of NHTSA. The Administrator reviews the fee set forth in this Appendix and, if appropriate, adjusts it by rule at least every 2 years.
For