Interpretation ID: nht73-4.18

DATE: 05/08/73

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: National Tire Dealers & Retreaders Association, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of March 21, 1973, in which you ask how retreaded tires are to be tested to the strength requirements (plunger-energy) of Standard No. 117 (S5.1.1, incorporating by reference S4.2.2.4 of Standard No. 109). You appear to believe testing to the requirement is precluded because Standard No. 117 contains no requirement that the cord material be labeled onto the tire, and the plunger-energy requirements specify different performance levels for differing cord materials.

While Standard No. 117 does not require the generic name of the cord material to be labeled onto the retreaded tire, we expect that it will be found on most tire casings and will be available to the retreader on all post "DOT" casings, and on many pre-DOT casings as well. If a retreaded tire is not labeled with its cord material, the strength test can still be conducted. It is not necessary to know the cord material before the plunger-energy values are obtained. Once they are obtained, a sample can be removed from the tire, from which the material can be determined.

March 21, 1973

Mr. Michael Pescoe, Counsel National Highway Traffic Safety Administration

We would like to forward to you a question on Federal Retread Standard 117 raised by one of the companies in the industry: "As specified in S4.2.2.4 Tire Strength, each tire shall meet the requirement for minimum breaking injuries specified in Table 2, when tested in accordance with S5.3 of Safety Standard 109. My question is, the labelling specification S6.3 has no provision for fabric identification. Without cord type the Plunger Energy test, as specified in F.M.V. S.S. 109, cannot be performed because of the different minimum force values for different types of cord. In other words the minimum force is 1650 lbs. for a Rayon tire with a cross section of 6 inches or above. While the specification is 2600 lbs. for Nylon and Polyester cord with the same cross section width. Cord identification is required for testing in compliance with M.V.S.S. 117. What do we do now?"

As soon as we receive your answer, we will forward it on to the company that requested it.

Phillip P. Priedlander, Jr. Director of Communications