Tire Size, Thread Depth, Width and Snow Chains Regulations (USA and Canada)
Required to be equipped with tire traction devices when entering a signed restricted area. There are three requirements in California. Requirement One (R1): Chains, traction devices or snow tires are required on the drive axle of all vehicles except four wheel/ all wheel drive vehicles. Requirement Two (R2): Chains or traction devices are required on all vehicles except four wheel/ all wheel drive vehicles with snow-tread tires on all four wheels. (NOTE: Four wheel/all wheel drive vehicles must carry traction devices in chain control areas.) Requirement Three (R3): Chains or traction devices are required on all vehicles, no exceptions. There is no requirement for trucks to carry chains during any specified time period.
27450. When any vehicle is equipped with any solid tire, the solid tire shall have a minimum thickness of resilient rubber as follows: (a) If the width of the tire is three inches but less than six inches, one inch thick. (b) If the width of the tire is six inches but not more than nine inches, 11/4 inches thick. (c) If the width of the tire is more than nine inches, 11/2 inches thick.
27451. The rubber of a solid tire shall be measured between the surface of the roadway and the nearest metal part of the base flange to which the tire is attached at the point where the concentrated weight of the vehicle bears upon the surface of the roadway.
27452. The required thickness of rubber shall extend evenly around the entire periphery of the tire. The entire solid tire shall be securely attached to the channel base and shall be without flat spots or bumpy rubber.
27453. There shall not be an average difference greater than 1/8 inch between the outside diameters of each single tire composing a dual solid rubber tire.
27454. No tire on any vehicle upon any highway shall have on its periphery any block, stud, flange, cleat, ridge, bead, or any other protuberance of metal or wood which projects beyond the tread of the traction surface of the tire.
This section does not apply to the following:
(a) Tire traction devices of reasonable size used to prevent skidding when upon wet surfaces or when upon snow or ice.
(b) Pneumatic tires which have embedded therein wire not to exceed 0.075 of an inch in diameter and which are so constructed that under no conditions will the percentage of metal in contact with the roadway exceed 5 percent of the total tire area in contact with the roadway, except that during the first 1,000 miles of use or operation of any such tire, the metal in contact with the roadway may exceed 5 percent of the tire area in contact with the roadway, but shall in no event exceed 20 percent of such area.
(c) Vehicles operated upon unimproved roadways when necessary in the construction or repair of highways.
(d) Traction engines or tractors when operated under the conditions of a permit first obtained from the Department of Transportation.
(e) Pneumatic tires containing metal-type studs of tungsten carbide or other suitable material and which are so inserted or constructed that under no conditions will the number of studs or the percentage of metal in contact with the roadway exceed 3 percent of the total tire area in contact with the roadway, between the first day of November and April 30. The commissioner, after consultation with the Department of Transportation, may extend the period during which studded pneumatic tires may be used in any area of the state for the protection of the public because of adverse weather conditions.
(f) Pneumatic tires used on an authorized emergency vehicle, as defined in Section 165, containing metal-type studs of tungsten carbide or other suitable material, if the studs are so inserted or constructed that under no conditions will the number of studs or the percentage of metal in contact with the roadway exceed 3 percent of the total tire area in contact with the roadway. Notwithstanding subdivision (e), authorized emergency vehicles are permitted the unrestricted use of studded pneumatic tires throughout the year.
27460. Any passenger vehicle or motortruck having an unladen weight of 6,500 pounds or less and operated and equipped with four-wheel drive and with snow-tread tires on all four drive wheels may be operated upon any portion of a highway without tire traction devices, notwithstanding the fact that the highway is signed for the requirement of those devices and provided that tire traction devices for at least one set of drive wheels are carried in or upon the vehicle. The snow-tread tires shall meet the requirements specified in Section 27459, and the vehicle shall not, when so operated, tow another vehicle except as may be necessary to move a disabled vehicle from the roadway.
No person shall use those tires on four-wheel drive vehicles in place of tire traction devices whenever weather and roadway conditions at the time are such that the stopping, tractive, and cornering abilities of the tires are not adequate or whenever the Department of Transportation or local authorities, in their respective jurisdictions, place signs prohibiting their operation unless equipped with tire traction devices.
(a) No dealer or person holding a retail seller’s permit shall sell, offer for sale, expose for sale, or install on a vehicle axle for use on a highway, a pneumatic tire when the tire has less than the tread depth specified in subdivision (b). This subdivision does not apply to any person who installs on a vehicle, as part of an emergency service rendered to a disabled vehicle upon a highway, a spare tire with which the disabled vehicle was equipped.
(b) No person shall use on a highway a pneumatic tire on a vehicle axle when the tire has less than the following tread depth, except when temporarily installed on a disabled vehicle as specified in subdivision (a):
One thirty-second (1/32) of an inch tread depth in any two adjacent grooves at any location of the tire, except as provided in paragraphs (2) and (3).
Four thirty-second (4/32) of an inch tread depth at all points in all major grooves on a tire on the steering axle of any motor vehicle specified in Section 34500, and two thirty-second (2/32) of an inch tread depth at all points in all major grooves on all other tires on the axles of these vehicles.
Six thirty-second (6/32) of an inch tread depth at all points in all major grooves on snow tires used in lieu of tire traction devices in posted tire traction device control areas.
(c) The measurement of tread depth shall not be made where tie bars, humps, or fillets are located.
(d) The requirements of this section shall not apply to implements of husbandry.
(e) The department, if it determines that such action is appropriate and in keeping with reasonable safety requirements, may adopt regulations establishing more stringent tread depth requirements than those specified in this section for those vehicles defined in Sections 322 and 545, and may adopt regulations establishing tread depth requirements different from those specified in this section for those vehicles listed in Section 34500.
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.