Everyone decides for themselves whether to drive on worn tires. However, it is worth remembering: trying to save on new tires can cost the lives of not only the driver but also those around them.
In Ukraine, the requirements for minimum tread depth are established in the document — order No. 33 of March 1, 2010. This regulatory act defines the list of technical means used by State Automobile Inspectorate units to record traffic violations. According to this document, for passenger cars and trucks with a maximum permissible weight of up to 3.5 tons, the remaining tread depth cannot be less than 1.6 mm. However, in practice, traffic inspectors do not have a certified device to accurately measure this indicator on the spot.
What is aquaplaning and slushplaning
If explained simply, aquaplaning is a situation when the wheels literally float above the road, and the car completely loses traction with the surface. The more worn the tread, the higher the likelihood of this effect. In addition, the braking distance increases. These are the conclusions reached by Nokian specialists during their own research.
Earlier, AvtoPortal wrote about a trip to a test track in Finland, where we learned about the influence of rolling resistance and observed the movement of an autonomous vehicle. In addition, we had the opportunity to try tires with different degrees of wear ourselves and feel the difference in car handling on wet asphalt.
Based on the tests conducted by Nokian, the following conclusions can be drawn. If tires are worn to a remaining tread depth of 1.6 mm, then on a road covered with a layer of water of about 5 mm, the risk of aquaplaning appears already at a speed of 76 km/h. For new tires, this threshold is higher — about 96 km/h.
There is also a phenomenon called slushplaning. In essence, it resembles aquaplaning, but it occurs not on water but on slush — the same wet snow slurry that forms during thaws. Simply put, it is sliding on slush.
When the tread is worn or the speed is too high, the tire stops coping with water evacuation. The reason is that the contact patch area between the tire and the road sharply decreases. The presented illustration shows how the size of the contact zone changes for tires with different tread depths at a water layer of 3 mm and a speed of 75 km/h. For a worn tire with a remaining tread depth of 1.6 mm, the contact patch occupies only 16% of what it would be for a stationary car.
How noticeably the braking distance lengthens when the tread is worn to 4 mm, and what sensations arise when driving through a puddle on fresh tires with a tread depth of 8 mm, is clearly shown in our video material:
Conclusion
If you value your own car and the safety of your loved ones, do not postpone tire replacement. Such a decision, of course, hits the budget, but the consequences of a collision with the vehicle ahead or driving off the road will cost significantly more. Especially do not squeeze the last kilometers out of the wheels, bringing them to a "bald" state. Even with a remaining tread depth of 4 mm, braking properties and vehicle stability on wet roads noticeably deteriorate. And what can we say about the minimum 1.6 mm...
