Minnesota Statutes Transportation (Ch. 160-174A) § 169.723. Tires considered unsafe

(1) any part of the ply or cord exposed; or

(2) any bump, bulge or separation; or

(3) a tread design depth of less than 2/32 (1/16) of an inch measured in the tread groove nearest the center of the tire at three locations equally spaced around the circumference of the tire, exclusive of tie bars or for those tires with tread wear indicators; or

(4) been worn to the level of the tread wear indicators in any two tread grooves at three locations; or

(5) a marking “not for highway use,” or “for racing purposes only,” or “unsafe for highway use;” or

(6) tread or sidewall cracks, cuts or snags deep enough to expose the body cords; or

(7) been regrooved or recut below the original tread design depth, except special taxicab tires which have extra undertread rubber and are identified as such.