C-24.2, r. 32 - Regulation respecting safety standards for road vehicles
178. The following are major defects:
(1) a tire that is so cut or worn that the cord shows or that has a bulge due to a fault in the carcass;
(2) a tire that has a tread less than 0.8 mm in depth measured in a main groove or sculpture, but not at the level of the wear indicator;
(3) a tire leaking air or that has foreign material deeply embedded in the tread or sidewall which could cause a puncture;
(4) a tire that touches or that could touch a fixed part of the vehicle;
(5) a part mounting the wheel to the axle that is missing, cracked, broken or insufficiently tight; and
(6) a wheel that has a crack, break or elongated bolt hole.