Do not trust appearances. Test your tires. Your life depends on it.

The quick reality

Tires can look fine while losing grip, inflating poorly, or aging into failure. Visual shine does not equal safety. Use objective checks that reveal what the eye misses.

A 60-second driveway check

1. Pressure: Measure cold pressure with a gauge. Use the placard on the driver door, not the sidewall max. Expect about 1 psi change for every 10°F change in temperature. Top up evenly across all four.
2. Tread depth: New tires are usually 8 to 9 mm. Replace at 3 to 4 mm for heavy rain, and at 5 mm for snow. The legal minimum is about 1.6 mm which is 2⁄32 in, but braking and aquaplane resistance drop long before that.
3. Wear pattern:
   • Center wear suggests over-inflation.
   • Edge wear suggests under-inflation or aggressive cornering.
   • One-side wear suggests alignment issues.
   • Feathering or cupping suggests worn shocks or imbalance.
4. Sidewalls: Look for cuts, bubbles, or visible cords. Any bulge means immediate replacement.
5. Objects and plugs: Remove stones from grooves. Inspect any repair. A plug in the tread can be OK if done correctly. Anything in the shoulder or sidewall is not safe.

Monthly deeper tests

• Age: Find the DOT code on the sidewall. The last four digits are week and year. Many manufacturers advise replacing by 6 years regardless of tread. Ten years is a hard stop even for spares.
• Rotation: Every 8,000 to 10,000 km helps even wear and maintains handling balance.
• Balance and alignment: If you feel vibration at a specific speed or the car pulls, schedule a shop check. Proper alignment shortens stopping distance and protects tires.
• Brake check: In an empty lot, perform a gentle stop from 30 km/h and a firm stop from 50 km/h. Listen for ABS chatter and feel for straight tracking. Longer distance or pull to one side is a signal to inspect brakes and tires together.

Wet weather and winter rules

• Rain: Tread channels water. Below 4 mm, hydroplaning risk rises sharply. Slow down in standing water and avoid cruise control in heavy rain.
• Snow and ice: Use winter-rated tires with the mountain-snowflake symbol. All-season rubber hardens in cold. Replace winter tires at 5 mm to keep bite edges working.

Load, speed, and heat

• Do not exceed the load index on the tire or the axle limits on the placard.
• High speed and under-inflation create heat which weakens the internal structure. A tire can fail even if the outside still looks healthy.

Repair and replace decisions

• Repairable: Small punctures in the tread area, fixed with a proper plug-patch from inside.
• Replace: Sidewall damage, shoulder punctures, repeated pressure loss, cords showing, bubbles, severe age cracking.

Smart habits that extend life

• Check pressures every month and before road trips.
• Use a quality gauge and keep valve caps on.
• Set torque correctly after wheel service and recheck after 80 to 100 km.
• Store off-season tires in a cool, dark place, inflated and clean.

A final reminder

Safety is measured, not guessed. Make the checks routine, act on what the numbers and wear patterns tell you, and treat tires as life-support equipment.