The grooves in the tread carry water away from under the tire so it keeps its grip. As the tire wears, the grooves get shallower and the tire grips a wet road less well. Replace the tire at the legal limit: the traffic rules require it, and for winter tires so does a technical regulation.
- minimum tread depth for a passenger car under Kazakhstan's rules
- 1.6 mm
- at this depth a winter tire with the snowflake symbol is unfit for snow and ice
- 4 mm
The legal limits
The list of faults that forbid driving is part of the Basic Provisions for admitting vehicles to operation. For tires it sets a minimum tread depth:
| Vehicle | Minimum tread depth |
|---|---|
| Passenger car | 1.6 mm |
| Truck | 1 mm |
| Bus | 2 mm |
| Motorcycle and moped | 0.8 mm |
You also may not drive on a tire if:
- a puncture, cut or tear exposes the cord;
- the carcass has separated, or the tread or sidewall is peeling away;
- tires on one axle differ in size, construction, model or tread pattern, or studded tires are mixed with non-studded ones.
Winter tires: a higher limit
The EAEU regulation on the safety of wheeled vehicles sets a higher limit for winter tires. A tire with the three-peak mountain and snowflake symbol is unfit for snow and ice once its tread is 4 mm deep or less. If your winter tires are down to about 4 mm in autumn, do not fit them for another season.
How to check wear yourself
- Park on level ground and turn the steering wheel so you can see the front tires.
- Find the wear indicators: small raised bars at the bottom of the main grooves. The sidewall marks where they are, with TWI, a triangle or the tire maker’s logo.
- If the tread is worn down to the indicator, about 1.6 mm is left. Replace the tire.
- For winter tires the indicator is not enough. Measure the depth with a tread gauge or caliper in three places around the tire. Each time, measure at both edges and in the middle of the tread.
Causes of uneven wear
When a tread wears unevenly, look at the pressure and the car before the tire. Where the wear is heaviest tells you which.
| Where it is worn | Likely cause | What to do |
|---|---|---|
| In the center | Pressure too high | Check pressure on cold tires and set the car maker’s value |
| On both edges | Pressure too low | Inflate to the correct pressure and check it once a month |
| On one edge or in patches | Wheel alignment or worn suspension | Have the alignment and suspension checked |
If the cause stays, new tires wear the same way. Find the cause first, then replace the tires.
When to go to a tire shop straight away
- The sidewall has a bulge. Replace the tire.
- A cut exposes the cord.
- The tire keeps losing pressure and you cannot see a puncture.
- The tread is worn to the indicator in places but still deep next to them.
At the tire shop the tire is taken off the wheel and checked from the inside. After hitting a pothole or curb, the cord can break inside while the tire looks fine from the outside.
Common questions
Where are the wear indicators?
At the bottom of the main grooves, spaced evenly around the tire. The sidewall marks where they are, with TWI, a triangle or the tire maker's logo.
The indicator shows 1.6 mm. Is that enough for a winter tire?
No. Under the EAEU technical regulation, a winter tire with the mountain and snowflake symbol is unfit for snow and ice at 4 mm. Measure the depth with a tread gauge or caliper.
Why has my tire worn on one side only?
Usually because the wheel alignment is out or suspension parts are worn. Have the alignment and suspension checked, or new tires will wear the same way.
Can I fit two different tires on one axle?
No. Kazakhstan's rules forbid tires of different size, construction, model or tread pattern on one axle, and studded tires mixed with non-studded ones.
Sources
Adilet legal database
Customs Union Commission
Tire Tread Depth: Legal Limits and What to Know
Michelin
How to Interpret Tyre Wear Indicator
Michelin
What can cause excessive or uneven tyre wear?
Michelin
Michelin
