Interpretation ID: nht74-1.15

DATE: 05/01/74

FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA

TO: The Mansfield Tire & Rubber Company

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of March 19, 1974, inquiring whether Motor Vehicle Safety Standard No. 109 permits the labeling of both the 175R13 and the BR78-13 tire size designations on the same tire.

Paragraph S4.3 of Standard No. 109 permits the labeling on the same tire of equivalent inch and metric size designations. Based upon the Tables in the Appendix of Standard No. 109, we would consider the two size designations to be equivalent inch and metric size designations, and both may therefore be labeled on the sidewall of the same tire.

Yours truly,

ATTACH.

Maximum Tire Loads (Pounds) At Various Cold Inflation Pressures Size 16 18 20 22 24 26 28 30 32 34 175R13 790 840 890 930 980 1030 1070 1110 1150 1190 BR78.13 780 840 890 930 980 1030 1070 1110 1150 1190

THE MANSFIELD TIRE & RUBBER COMPANY

March 19, 1974

L. R. Schneider -- Chief Counsel, National Highway Traffic Safety Administration, United States Department of Transportation

Dear Mr. Schneider:

In the Federal Register November 1, 1973, Part III, the Department of Transportation published Passenger Car Tires and Rims Information under MVSS 109. Reviewing Rules and Regulations for Radial Ply Tires, it is noted that under Table I-H for the 175R-13 and under Table I-H for the BR78-13, the loads, inflations, rim, minimum size factor and section width are basically the same. For your observation, we are listing from the Tables both of these sizes as spelled out in these Rules and Regulations.

Maximum Tire Loads (Pounds) At Various Cold Inflation Pressures Test Min.

Rim Size Sect.

Width Fact. Width Size 36 38 40 (In.) (In.) (In.) 175R13 1230 1270 1300 4 1/2 30.30 6.75 BR78.13 1230 1270 1300 4 1/2 30.31 6.75

As these tires are both the same for the American size radial and the millimeter radial, it is our intent to mark both these sizes, as noted in MVSS 109, Part 571, Section S4.3 "Labeling Requirements", on the same tire with the maximum load and inflation branded on the tires. We are intending to use the American size tire code in the tire identification serial.

We will appreciate your reviewing this matter and unless advised to the contrary, we are intending to proceed with the marking as described above. We will appreciate hearing from you at your earliest convenience.

Sincerely,

R. C. Hudson -- Director, Tire Engineering, Tech Service/Quality Control