49 CFR 569.7 - Requirements.
(a) Regrooved tires. (1) Except as permitted by paragraph (a)(2) of this section, no person shall sell, offer for sale, or introduce or deliver for introduction into interstate commerce regrooved tires produced by removing rubber from the surface of a worn tire tread to generate a new tread pattern. Any person who regrooves tires and leases them to owners or operators of motor vehicles and any person who regrooves his own tires for use on motor vehicles is considered to be a person delivering for introduction into interstate commerce within the meaning of this part.
(2) A regrooved tire may be sold, offered for sale, or introduced for sale or delivered for introduction into interstate commerce only if it conforms to each of the following requirements:
(i) The tire being regrooved shall be a regroovable tire;
(ii) After regrooving, cord material below the grooves shall have a protective covering of tread material at least 3/32-inch thick;
(iii) After regrooving, the new grooves generated into the tread material and any residual original molded tread groove which is at or below the new regrooved depth shall have a minimum of 90 linear inches of tread edges per linear foot of the circumference;
(iv) After regrooving, the new groove width generated into the tread material shall be a minimum of 3/16-inch and a maximum of 5/16-inch;
(v) After regrooving, all new grooves cut into the tread shall provide unobstructed fluid escape passages; and
(vi) After regrooving, the tire shall not contain any of the following defects, as determined by a visual examination of the tire either mounted on the rim, or dismounted, whichever is applicable:
(A) Cracking which extends to the fabric,
(B) Groove cracks or wear extending to the fabric, or
(C) Evidence of ply, tread, or sidewall separation;
(vii) If the tire is siped by cutting the tread surface without removing rubber, the tire cord material shall not be damaged as a result of the siping process, and no sipe shall be deeper than the original or retread groove depth.
(b) Siped regroovable tires. No person shall sell, offer for sale, or introduce for sale or deliver for introduction into interstate commerce a regroovable tire that has been siped by cutting the tread surface without removing rubber if the tire cord material is damaged as a result of the siping process, or if the tire is siped deeper than the original or retread groove depth.