How important are the tires and the wheels that roll under every driver and passenger?
Important enough that states and the federal government have guidelines and regulations about the condition of tires, and according to the Wisconsin Highway Patrol, their inspectors are coming across tire violators on a regular basis.
“Bald tires can be dangerous on any vehicle – especially when cords are showing,” WSP posted on its social media along with an offending photo. “This is just one example of what WSP inspectors come across during daily commercial motor vehicle inspections.”
According to Wisconsin law, a tire must have at least 2/32” of tread depth, with the exception of a steer tire on a commercial motor vehicle which needs a minimum of 4/32″ of depth.
Federal regulations, specifically, Federal Motor Carrier Safety Administration (FMCSA) regulation 5.1.14 states, “Tires on commercial motor vehicles must meet safety standards, including load restrictions, inflation pressure, and other safety standards, and be free from specified defects.”
In more detail, 49 CFR 393.75 gives more specific guidelines on tire usage, wear and weight guidleines.
To begin with, no motor vehicle shall be operated on any tire that has body ply or belt material exposed through the tread or sidewall, has any tread or sidewall separation, is flat or has an audible leak, or has a cut to the extent that the ply or belt material is exposed.
Further, any tire on the front wheels of a bus, truck, or truck tractor shall have a tread groove pattern depth of at least 4⁄32 of an inch when measured at any point on a major tread groove. The measurements shall not be made where tie bars, humps, or fillets are located.
Tires shall have a tread groove pattern depth of at least 2⁄32 of an inch when measured in a major tread groove. The measurement shall not be made where tie bars, humps or fillets are located.
A regrooved tire with a load-carrying capacity equal to or greater than 2,232 kg (4,920 pounds) shall not be used on the front wheels of any truck or truck tractor.
No motor vehicle may be operated with speed-restricted tires labeled with a maximum speed of 55 mph or less in accordance with S6.5(e) of FMVSS No. 119 at speeds that exceed the rated limit of the tire.
No motor vehicle, except manufactured homes, shall be operated with tires that carry a weight greater than that marked on the sidewall of the tire or, in the absence of such a marking, a weight greater than that specified for the tires in any of the publications of any of the organizations listed in Federal Motor Vehicle Safety Standards.
The only exceptions include if the vehicle is being operated under the terms of a special permit issued by the state, and
the vehicle is being operated at a reduced speed to compensate for the tire loading in excess of the manufacturer’s rated capacity for the tire. In no case shall the speed exceed 80 km/hr (50 mph).
Also, no motor vehicle shall be operated on a tire which has a cold inflation pressure less than that specified for the load being carried.
Bruce Guthrie is an award-winning journalist who has lived in three states including Arkansas, Missouri and Georgia. During his nearly 20-year career, Bruce has served as managing editor and sports editor for numerous publications. He and his wife, Dana, who is also a journalist, are based in Carrollton, Georgia.
