Interpretation ID: nht80-1.9

DATE: 02/06/80

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: The Yokohama Rubber Co., Ltd.

TITLE: FMVSS INTERPRETATION

TEXT: Your September 10, 1979, letter to our Tire Division has been referred to me for reply, since you are requesting an interpretation of Federal Motor Vehicle Safety Standard No. 119 (49 CFR @ 571.119). You asked two questions in your letter. First, you asked whether the definition you offered for "maximum speed" was correct. If it was correct, you stated that the tire could exceed the speed restriction shown on the tire at a lighter load, and showed how the information could be set forth on the tire. The listing of varying maximum loads at different maximum speeds is not permitted to appear on the tire. Second, you asked if speed restricted tires could specify a speed restriction other than the 35, 50, and 55 mile per hour (mph) restrictions shown in the endurance test schedule of Standard No. 119. The answer to this question is no.

Regarding your first question, you defined a tire's maximum speed as "the highest speed at which a tire can carry the maximum single load that is molded on the tire sidewall." This definition is an acceptable one for tires with a speed restriction listed for them. However, you went on to note that if this definition was acceptable, then a tire could list varying maximum loads at varying maximum speeds. Such a listing is expressly prohibited by the language of Standard No. 119.

S6.5 of Standard No. 119 specifies that each tire subject to the Standard shall be marked with the information that is set forth in following paragraphs. Paragraph (d) of S6.5 requires the maximum load rating and corresponding inflation pressures for single load tires, the type of tire about which you are inquiring, to appear as: Max load lbs. at psi cold. Paragraph (e) of S6.5 requires that a speed restriction on the tire appear only as: Max speed mph. Hence, a single load tire can be labeled with only one maximum load and only one maximum speed.

Your second question was whether a manufacturer could restrict the speed of a tire subject to Standard No. 119 to a speed other than the three speed restrictions shown in Table III of the Standard. Paragraph S6.1 requires all tires to pass the endurance test requirements of the Standard, and Table III shows the load and speeds to which the tires will be subjected during the endurance test. If the tire being subjected to the endurance test does not qualify for the special speeds and loads as one of the three speed restricted tires shown in the table or as a motorcycle tire, the tire would be tested at the speed and load shown under the heading "All other". This would mean that the tire's speed restriction would be ignored for purposes of the endurance test, and it would be tested as if it were a non-speed restricted tire. Such a tire would presumably fail the endurance test under these conditions, and no tire which fails to pass the endurance test can be sold in the United States. As a practical matter, therefore, speed restrictions other than the three shown in Table III of the Standard are not recognized by this agency.

The three speed restrictions shown in Table III of the Standard were adopted from descriptions of three types of speed restricted tires used by the United States tire industry in 1972, when the agency was initially promulgating Standard No. 119. If your company would like to add another speed restriction to those shown in Table III, you should file a petition for rulemaking with this agency requesting an amendment to Standard No. 119.

Sincerely,

ATTACH.

September 10, 1979

Tire Division, National Highway Safety Administration,

Re: Confirmation of the definition of Max. Speed

Dear Sirs,

We would like to confirm that meaning of Max. Speed specified in S6.5e of FMVSS No. 119 is as follow:

1 Max. Speed means the highest speed at which a tire can carry the max. single load that is molded on the tire sidewall.

If the actual carrying load is lower than max. single load, the tire can run at a higher speed than the Max. Speed molded on the tire sidewall.

Example

Tire Size 1000R20 Load range H

Max. Load single 6610lbs

Max. Speed 35MPH Load LBS Speed MPH 6610 Max. Load 35 Max. Speed 5300 42 4600 50

2 According to Table Endurance Test Schedule, Max. Speed For Speed-restricted Service is specified as 55, 50 or 35 MPH. May we choose speeds different from the above?

In this case, if Max. Speed chosen is 40 MPH, should the 50 MPH endurance test condition be used?

We would appreciate it very much if you would give careful consideration to our questions.

Very truly yours,

The Yokohama Rubber Co., LTD -- Tire Quality Assurance Department; Taiji Ide, Manager