Tread Depth
Tread Depth is a vertical measurement of a tire’s grooves (also known as channels, or tread void). Federal Motor Carrier Administration (FMCSA) regulations require all trailers to have a minimum Tread Depth of 2/32″. The tires on buses, trucks, and truck tractors must have a minimum tread depth of 4/32″.
FMCSA Tread Depth Regulations
Steer Tires
According to Federal Motor Carrier Safety Administration (FMCSA) regulations, steer tires must have a minimum tread depth of 4/32″.
49 CFR 393.75(b)
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.
Trailer Tires
According to Federal Motor Carrier Safety Administration (FMCSA) regulations, trailer tires must have a minimum tread depth of 2/32″.
49 CFR 393.75(c)
Except as provided in paragraph (b) of this section, 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.
More Info
Visit the Federal Motor Carrier Safety Administration (FMCSA) for current regulations.