Tire Size, Thread Depth, Width and Snow Chains Regulations (USA and Canada)
(a) A person shall not operate on a public highway of this state a vehicle or special mobile equipment which has metal or plastic track or a tire which is equipped with metal that comes in contact with the surface of the road or which has a partial contact of metal or plastic with the surface of the road, except as provided in subsections (c), (d), and (e).
(b) A person shall not operate on a highway a vehicle which has a tire that has on its periphery a block, stud, flange, cleat, spike, or other protuberance of a material other than rubber which projects beyond the tread of the traction surface of the tire, except as provided in subsections (c), (d), and (e). A person may, however, use farm machinery with a tire having a protuberance which will not injure a highway. A person may also use a tire chain of reasonable proportion upon a vehicle when required for safety because of snow, ice, or other condition tending to cause a vehicle to skid.
(c) A person may operate on a highway a vehicle which has a pneumatic tire in which wire of .075 inches in diameter or less is embedded if the tire is constructed so that the percent of metal in contact with the highway does not exceed 5% of the total tire area in contact with the roadway, except that during the first 1,000 miles of use or operation of the tire the metal in contact with the highway shall not exceed 20% of the area.
(d) The department of state highways and transportation shall promulgate rules establishing acceptable standards to permit the use of a tire with studs or other traction devices to be used on a street or highway after April 1, 1975. The rules shall make separate provision for the extreme winter snow and ice conditions of the Upper Peninsula and the northern Lower Peninsula. The rules shall include a restriction on the amount and dimension of protrusions that may be allowed on a tire, the type of material that may be used in a stud, traction device, or tire, and the amount of road wear that a tire with studs or other traction devices may cause on a street or highway.
(e) A person may operate on a highway a vehicle which has a pneumatic tire in which are inserted ice grips or tire studs if the person is a law enforcement officer operating a vehicle owned by a law enforcement agency, a person operating an ambulance, or a United States postal service rural carrier driving a vehicle the rural carrier owns and maintains as a prerequisite to employment in the postal service.
(f) A person shall not operate a vehicle on a highway when a tire in use on that vehicle is unsafe as provided in subsection (h).
(g) A person in the business of selling tires shall not sell or offer for sale for highway use a tire which is unsafe as provided in subsection (h).
(h) A tire is unsafe if it is in any of the following conditions:
(i) Has a part of the belting material, tire cords, or plys exposed.
(ii) Has evidence of cord or tread separations.
(iii) Is worn to or below the minimum tread level in 2 or more adjacent major grooves at 3 or more locations spaced around the circumference of the tire. Minimum allowable tread levels are as follows:
weighing less than 10,000 pounds……………………………2/32 inch front and rear
vehicles weighing 10,000 pounds or more………………………4/32 inch front and 2/32 rear
Measurements shall not be made at locations of tread wear indicators or tie bars. A motor vehicle licensed as an historic vehicle under section 803a is exempt from the tread depth requirements of this subsection.
(iv) Has a marking “not for highway use”, “for racing purposes only”, “for farm use only”, or “unsafe for highway use”.
(v) Has been regrooved or recut below the original tread design depth except in the case of special purpose designed tires having extra under tread rubber provided for this purpose and identified as those tires.
Permissible upon any vehicle when required for safety because of snow, ice, or other conditions tending to cause a vehicle to skid.
Below is a list of states and their tire regulations.
Click on the states below for links to the state's guidelines for for tire regulations for commercial vehicles / heavy haul shipping. These regulations are subject to change for each state. If something doesn't look correct, give us a shout and let us know so we can property update the page.