- Tires are considered to be worn out at 2/32 inch minimum tread depth.
- In wet conditions 4/32 inch or less tread means a significant loss of wet traction due to shallower grooves and sipes.
- In snow conditions, traction noticeably diminishes at 6/32 inch tread depth. Shallower lug and groove depths limit a tire's ability to "bite" into snow and clean out snow compressed into the tread.
- Irregular wear necessitates early tire replacement.