Mr. Douglas J. Shoner

S.E.M. Co.

12244 Truro Avenue

Hawthorne, CA 90250

Dear Mr. Shoner:

This responds to your letter asking which Federal standards would apply to what you call flat-proofed tires, which you state are tires equipped with the system you described as a Cellular Tire Liner and Air Chamber System for Pneumatic Tires. According to your letter, the tire liners consist of an elastometric cellular structure comprising a multiplicity of elastometric cells. You also state that your system equips the inside of a pneumatic tire with both an elastometric cellular tire insert, and an air chamber pressurized with air, resulting in a tire partially filled with foam, and partially filled with pressurized air.

By way of background, the National Highway Traffic Safety Administration (NHTSA) is authorized to issue Federal motor vehicle safety standards that set performance requirements for new motor vehicles and items of motor vehicle equipment (see 49 U.S.C. Chapter 301). NHTSA does not provide approvals of motor vehicles or motor vehicle equipment. Instead, manufacturers are required to self-certify that their products conform to all applicable safety standards that are in effect on the date of manufacture. NHTSA selects a sampling of new vehicles and equipment each year to determine their compliance with applicable regulations. If our testing or examination reveals an apparent noncompliance, we may require the manufacturer to remedy the noncompliance, and may initiate an enforcement proceeding if necessary to ensure that the manufacturer takes appropriate action.

Your letter raises the issue of whether a tire equipped with the tire insert you described would be a pneumatic tire under our standards, and thus regulated under a standard such as Federal Motor Vehicle Safety Standard (FMVSS) No. 109, New Pneumatic Tires, or one of the other standards that apply to pneumatic tires. Our answer is yes; your tire would qualify as a pneumatic tire, and therefore would be regulated as a pneumatic tire by NHTSA. Paragraph S3 of Standard No. 109 states that:

Pneumatic tire means a mechanical device made of rubber, chemicals, fabric and steel or other materials, which, when mounted on an automotive wheel, provides the traction and contains the gas or fluid that sustains the load. (Emphasis added)

In this case, because the tire is filled with an air cavity in addition to the foam, we believe that it meets the definition of a pneumatic tire. We note that your tire differs from a tire addressed in a September 2, 1986 interpretation to Mr. Andrew A. Kroll, in which we stated that Standard No. 109 does not apply to foam-filled tires. In that Kroll letter, the tire at issue was completely filled with foam, and there was no pressurized air or fluid in the tires. In that letter, NHTSA stated that the foam itself did not qualify as a gas or fluid, and that therefore the tires were not pneumatic tires. In the case of your tires, we consider these tires to be pneumatic because of the existence of the pressurized air cavity in the tire.

In addition to Standard No. 109, various other Standards may apply to tires containing your tire insert. If the tires are used for vehicles other than passenger vehicles, Standard No. 119, New Pneumatic Tires for Vehicles Other Than Passenger Cars, applies. If they are radial tires, Standard No. 139, New Pneumatic Radial Tires for Light Vehicles, would apply. If the tires are retreaded, Standard No. 117, Retreaded Pneumatic Tires, may apply. Finally, all tire manufacturers are subject to the requirements of 49 CFR part 574, Tire Identification and Recordkeeping.

We are enclosing a copy of the 1986 Kroll letter mentioned above, as it may be useful to your understanding of this issue. Please note the discussion in the Kroll letter about the tires being items of motor vehicle equipment subject to NHTSAs defect investigation and recall authority. This discussion applies to your tires as well, since your tires are also items of motor vehicle equipment. Manufacturers of motor vehicles and motor vehicle equipment must ensure that their products are free of safety-related defects.

If you have any further questions, please contact Ari Scott of my staff at (202) 366-2992.

Sincerely yours,

Anthony M. Cooke

Chief Counsel

Enclosure

ref:109

d.4/26/07