Interpretation ID: nht75-2.22

DATE: 09/18/75

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

TO: Michelin Tire Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of July 9, 1975, inquiring as to the proper designation of plies on a truck tire constructed with two polyamide plies in the casing and two steel plies in the belt.

The designation that you suggested ("Tread: 2 Steel Plies; Sidewall: 2 Polyamide Plies") is incorrect. The designation on such a tire should indicate the presence of four plies in the tread area and two in the sidewall area (with compositions in each case).

Yours truly,

ATTACH.

JULY 9, 1975

Administrator -- National Highway Traffic Safety Administration, Department of Transportation

Dear Sir:

The Michelin Tire Corporation will be offering for sale in the U.S.A. truck tires which contain casing plies made of polyamide and belts made of steel.

A typical tire would be constructed with two polyamide plies in the casing and two steel plies in the belt.

Pursuant to paragraph S6.5(f) of Federal Motor Vehicle Safety Standard 119, we will mark such a tire as follows: Tread: 2 Steel Plies Sidewall: 2 Polyamide Plies

Please advise us if this does not comply with the requirements of the regulation.

Thank you.

Yours truly,

MICHELIN TIRE CORPORATION Technical Group;

John B. White -- Engineering Manager, Technical Information Dept.