October 15, 2026Minimum depth, wear bars, inside wear or cupping: how to read your tires' wear and know when to replace them.
Minimum tread depth
A tire whose tread drops below 1.6 mm (2/32 inch) is worn out and must be replaced. Wear bars, small bars moulded at the bottom of the grooves, become level with the tread at that depth. For a winter tire, don't wait for that threshold: below about 4 mm it clears snow and slush poorly.
- ✓Measure with a tread depth gauge, sold for a few dollars
- ✓Measure in several places: the centre and both edges
- ✓Think about age too: a tire hardens over the years, even with little wear
What uneven wear tells you
The way a tire wears often reveals another problem to fix, or new tires will wear the same way.
- ✓Worn on the inside or outside edge: alignment problem
- ✓Worn in the centre: overinflated tires
- ✓Worn on both edges: underinflated tires
- ✓Cupping (scalloped wear): tired shocks or alignment to check
Making tires last
Check the pressure once a month, cold, according to the sticker on the driver's door. Rotate tires according to the manufacturer's recommendations, and have the alignment checked after hitting a pothole or a curb.
When to go to the garage
Use the seasonal change: the garage can measure tread depth, spot uneven wear and check alignment while mounting your tires.
