Tire Size, Thread Depth, Width and Snow Chains Regulations (USA and Canada)
19VAC30-70-500. Tires, Wheels, Rims.
Inspect for and reject if:
1. Any tire is marked specifically for use other than on the highway, such as “For Farm Use Only,” “For Off-Highway Use Only,” any tire marked “Not for Steering Axle,” “For Mobile Home Use Only,” or “For Trailer Use Only.”
2. A radial tire is mismatched on the same axle with a bias ply tire or a bias belted tire.
3. Bias ply or bias belted tires are used on the rear axle when radial ply tires are used on the front axle. Except:
a. On a two-axle vehicle equipped with truck tires with 20-inch rim diameter and larger. Bias or radial tires may be used on either axle if the vehicle has dual rear wheels or is equipped with wide-base single tires.
b. Either bias or radial tires may be used on the steering axle of vehicles with three or more axles.
4. Bias tires and radial tires are mixed in a tandem-drive axle combination on a vehicle equipped with truck tires with 20-inch rim diameter and larger.
5. Any tire on the front wheel of a bus, truck or any tractor truck has a tread groove pattern of less than 4/32 inch when measured at any point on a major tread groove.
6. Any bus has regrooved, recapped, or retreaded tires on the front wheels.
7. Any motor vehicle, trailer or semitrailer, except the dual wheels installed on motor vehicles having seats for more than seven passengers: (i) operated wholly within a municipality, or (ii) operated by urban and suburban bus lines, which are defined as bus lines operating over regularly scheduled routes and the majority of whose passengers use the buses for traveling a distance of not exceeding 40 miles, measured one way, on the same day between their place of abode and their place of work, shopping areas, or schools, is equipped with a tire that has a tread depth measuring less than 2/32 of an inch when measured as follows: The exemptions provided in clauses (i) and (ii) of this paragraph do not apply to buses owned or operated by any public school district, private school, or contract operator of buses.
Measure in two adjacent tread grooves where tread is thinnest. If either of the grooves measure 2/32 of an inch or more, no further measurements are necessary and tread depth is satisfactory. Do not measure on tread wear indicators.
If both adjacent grooves measure less than 2/32 of an inch, the tire tread depth must be measured again at two additional equally spaced intervals around the circumference of the tire in a like manner as the first measurement. If the tread depth is less than 2/32 of an inch in two adjacent tread grooves at each of the equally spaced intervals, the tire must be rejected.
Refer to Figures 1, 2, 3, and 4 in this section for illustrations of how to measure tire tread.
IF THE DEPTH IS LESS THAN 2/32-INCH IN BOTH GROOVES MEASURE AT TWO ADDITIONAL EQUALLY SPACED INTERVALS
8. A tire equipped with tread wear indicators if found to have such indicators in contact with the pavement in any two adjacent grooves at three equally spaced intervals around the circumference of the tire.
9. Any tire has a cut to the extent a ply or belt material is exposed or puncture, not to include a plug or patch that may be used as a manner of repair.
Plugs/patches shall be in the tread area only. Plugs/patches are not permitted in the sidewall of the tire.
10. Any tire is worn so that the fabric or steel cord is visible.
11. Any tire has knots or bulges in its sidewalls or if there is evidence of a broken belt under the tread, or if the tread is separating from the fabric.
12. Any tire that has been recut or regrooved except commercial tires so designed and constructed to provide for acceptable and safe recutting and regrooving. Each tire that has been regrooved must be labeled with the word “Regroovable” molded on or into the tire on both sidewalls in raised or recessed letters.
13. Any tire is flat or has an audible air leak.
14. Any tire so mounted or inflated that it comes into contact with its mate or any parts of the vehicle.
15. Rims, or lock rings or wheels are bent, cracked or damaged so as to affect safe operation of the vehicle. Reject if lug nut holes are elongated (out of round).
16. Any wheel studs, bolts, nuts, lugs, or other fasteners (both spoke and disc wheels) are loose, broken, cracked, stripped, missing, or damaged or otherwise ineffective.
17. Any welded repair on aluminum wheel(s) on a steering axle or any welded repair (other than disc to rim attachment) on steel drive wheel(s) mounted on the steering axle.
18. Directional tires and/or wheels, designed and manufactured to go in a certain direction of rotation not installed in the proper direction of rotation.
Permissible when required for safety because of snow, ice, or other conditions tending to cause a vehicle to slide or skid. It shall also be permissible to use on any vehicle whose gross weight does not exceed 10,000 pounds tires with studs which project no more than one-sixteenth of an inch beyond the tread of the traction surface of the tire when compressed if the studs cover no more than three percent of the traction surface of the tire. The use of studded tires is only permissible between October 15 to April 15.
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.