Have you damaged your tyre? Would you like to replace one, because the other still has more than half the tread? Better to change both – as required by the regulations[1]. The Polish Tyre Industry Association (PZPO) together with TÜV SÜD conducted a TEST, which confirms that the difference in tread depth between tyres on the same axle is dangerous and drastically reduces the car's grip – especially on wet surfaces. The car's safety systems cannot compensate for this. Tyres on the same axle of the vehicle have to be always changed in pairs. Therefore, car workshops should strictly adhere to this rule, and insurers are required to cover the costs for 2 tyres on an axle, not one.
The difference in safety, car handling, braking and grip when the tread depth of the tyres on the same axle is different is huge. The driver's control over the car is reduced and no advanced systems can cope with this problem. This is demonstrated by the track tests carried out in August this year.
Link to the video: https://oponymajamoc.pl/prawidlowe-cisnienie/
Polish regulations assume that tyres mounted on one axle should be identical. This means the same model, same tread, same size and same speed and load ratings.
– The regulations are clear on this matter: tyres on the same axle must have the same structure, shape and tread pattern. A sculpture is understood to mean both the pattern and the height – explains Filip Raszewski, Skoda Auto School.
There are many important elements in a car that affect the quality of driving and the state of safety. However, few are able to match the tyres. Why? Because the tyres are the only car system that touches the road. And the only one non-metallic that rotates so fast.
– Unfortunately, many diagnosticians only verify the tread pattern, they are not interested in its depth. The same approach is followed by motor vehicle claim adjusters – ads Marek Nytko, TÜV SÜD Poland.
Tyres are responsible for many important functions. Grip, steerability and road safety depend on them. The different tread heights on one axle mainly make the car unable to go straight. The car will pull in the direction where the tread is significantly lower.
– Paying the cost of just one damaged tyre is a common practice when settling insurance claims. The test and report by TÜV SÜD clearly show that only two tyres with the same pattern and tread depth will provide the necessary grip necessary for the proper functioning of the car's safety systems – underlines Piotr Sarnecki, General Director of the Polish Tyre Industry Association (PTIA).
– Often, relevant notes are also placed in the vehicle's operating manual. And if we have a car with a permanent 4x4 drive, then – apart from a certain technically permitted tolerance – we have to replace all the tyres. Failure to comply with these provisions may result in damage to the drive train and refusal to repair under the warranty – ads Sarnecki.
Of course, if you go to a professional tyre service – for example, one with a PTIA Tyre Certificate – they will pay attention to it, because they know what dangers it is. Therefore, it is always worth choosing a professional service that will remember to replace the tyres in pairs and will not destroy them during assembly. This is why the Polish Tyre Industry Association, together with the independent certification company TÜV SÜD, has introduced a system for assessing and awarding professional services based on an independent audit of equipment, servicing and qualifications of technical personnel, so that the driver does not have to habilitate in replacing and repairing tyres. Safe service is your safety!
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[1] Regulation of the Minister of Infrastructure on the technical conditions of vehicles and the scope of their necessary equipment, Journal Of Laws of 2016, item 2022
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