Interpretation ID: aiam0315
c/o Barnett Sales and Service
3710 Oxford Boulevard
Maplewood
MO 63143;
Dear Mr. Barnett: This is in reply to your letter of February 23, 1971, requesting advic on the acceptability of your regrooving pattern for regrooved tires.; Enclosed is a copy of the Rules and Regulations on regrooved an regroovable tires as it appears in the *Federal Register* published January 24, 1969, under Section 369.7(a)(3) Requirements, '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 groove depth, shall have a minimum of 90 linear inches of tread edges per linear foot of tire circumference.'; There are no measurements on your drawings to assist us in determinin if your zig-zag grooves and the three circumferencial grooves measure 90 linear inches. Three *straight* circumferential grooves would only provide approximately 72 linear inches.; The use of lateral cuts should substantially increase the tread edg measurements, providing the lateral cuts are from shoulder to shoulder to allow unobstructed fluid escape passages as required in Section 369.7(a)(5); Thank you for your interest in tire safety. Francis Armstrong, Director, Office of Standards Enforcement, Moto Vehicle Programs;