Minnesota Administrative Rules

CHAPTER 7445, PASSENGER AUTOMOBILE TIRES

DEPARTMENT OF PUBLIC SAFETY

7445.0100 DEFINITIONS.

Subpart 1.

Scope.

For the purposes of this chapter, the following terms shall have meanings ascribed to them.

Subp. 2.

Bead.

"Bead" means the part of the tire which is shaped to fit the wheel rim.

Subp. 3.

Cord.

"Cord" means the strands forming the plies in the tires.

Subp. 4.

Groove.

"Groove" means the space between two adjacent tread ribs.

Subp. 5.

Ply.

"Ply" means a layer of rubber-coated parallel cords.

Subp. 6.

Sidewall.

"Sidewall" means that portion of the tire between tread and bead.

Subp. 7.

Tie bar.

"Tie bar" means a transverse rubber rib manufactured into some tire treads to give lateral stability to tread ribs.

Subp. 8.

Tread.

"Tread" means that portion of the outer surface of the tire that is designed to come into contact with the road surface.

Subp. 9.

Tread design depth.

"Tread design depth" means the distance, measured near the centerline of the tire, from the base of the tread design to the top of the tread.

Subp. 10.

Tread rib.

"Tread rib" means the tread section running circumferentially around the tire.

Subp. 11.

Tread wear indicator.

"Tread wear indicator" means material molded during the manufacturing process into the bottom of tread grooves and designed to visibly disrupt the tread pattern when the tread design depth has worn to a depth of 2/32 of an inch.

Statutory Authority:

MS s 169.722

Published Electronically:

May 13, 1997

7445.0200 PURPOSE AND AUTHORITY.

Subpart 1.

Purpose.

The purpose of parts 7445.0100 to 7445.0300 is to establish minimum standards for the safe operating conditions of tires in use on passenger automobiles, station wagons, and other highway-use motor vehicles using passenger automobile-type tires.

Subp. 2.

Authority.

Parts 7445.0100 to 7445.0300 are promulgated pursuant to the authority granted by Minnesota Statutes 1976, section 169.722.

Statutory Authority:

MS s 169.722

Published Electronically:

May 13, 1997

7445.0300 UNSAFE TIRES.

A tire is unsafe and unlawful if one or more of the following conditions exists:

A.

there is any part of the ply or cord exposed;

B.

there is a separation that may be indicated by a bump or bulge of the sidewall, tread, or ply;

C.

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

D.

it is worn to the level of the tread wear indicators in any two tread grooves at three locations;

E.

it is marked "not for highway use," "for racing purposes only," "unsafe for highway use," or any similar marking indicating the tire is not designed for highway use;

F.

the tread or sidewall has cracks, cuts, or snags deep enough to expose the body cords; or

G.

it has been regrooved or recut below the original tread design depth, except certain taxicab tires that have additional under-tread rubber and are specifically identified as such by use of the word "regrooveable" molded on or into each sidewall of the tire.

Statutory Authority:

MS s 169.722

Published Electronically:

May 13, 1997