There is a popular opinion that all-season tires are a cure-all solution for motorists, and can even in certain cases perform better than dedicated winter tires, in spite of the manufacturers’ advice to have your summer tires replaced with winter ones at temperatures below 7 °C.
In order to find out more about the behavior of summer, all-season, and winter tires at different temperatures, the Tyre Reviews website conducted a special test, the results of which may go a long way to bust the misconceptions and carelessness of some motorists.
Different tires, different temperatures
The test of winter, summer, and all-season tires was conducted in six different temperature modes: -9°C, 0°C, 2°C, 6°C, 10°C, and 15°C. Measuring the influence of temperature on tires, or, rather, on their operational properties, chief of them being the braking distance, was only made possible thanks to the use of the indoor test facilities of the Test World complex in Finland.
The test involved five premium-class tire models in size 205/55 R16. The test car was a VW Golf of the 7th generation.
List of models tested:
- Continental AllSeasonContact — all-season tire
- Continental PremiumContact 6 — summer tire
- Continental WinterContact TS 860 — European winter tire
- Michelin CrossClimate — summer tire with winter capabilities (all-season)
- Nokian Hakkapeliitta R3 — Nordic winter tire
The tires were put through three test disciplines, each one of them conducted at different temperatures:
Measuring the tires’ wet braking performance was done consecutively at 2°C, 6°C, 10°C, and 15°C. In this discipline, it was not without surprises. First of all, even at 2°C, the winter tires of the European type demonstrate a weaker braking performance than the all-season tires Continental AllSeasonContact and Michelin CrossClimate, even though the difference is not that drastic. The leadership of the all-season tires only strengthened with the growth of the temperature.
Yet another surprise was the fact that even at 10°C the summer tires could not surpass the all-season models. Again, however, the differences were all but negligible. The Continental PremiumContact 6 summer model was only able to get ahead when the air temperature in the indoor facility was set at 15°C.
Still another surprise was the long braking distance demonstrated by the winter tires of the Nordic type. Let’s not forget, however, that these tires are engineered to ensure dependable traction on snow and ice, which by definition rules out the possibility of top-class wet braking.
The test conducted at -9°C did not bring any unexpected results. The shortest lap time on the indoor snow track was shown by the Nordic tires Nokian Hakapeliitta R3. The test pilot emphasized that with these tires he did not have the characteristic feeling of one’s tires slipping underneath the car, and that these tires performed with much greater confidence than Continental WinterContact TS 860, who came the second.
Please take notice that the gap between the all-season and winter tires was not as dramatic as between the results of the summer tires.
Yet another braking test, which was this time conducted at 0°C, 2°C, 5°C, and 8°C. In all of the temperature modes, the shortest braking distance was demonstrated by the summer tires. The worst performance, says the technical expert of Shina Guide, was shown by the Nordic winter tires. Against their background, the European winter tires looked more convincing, yet they were still worse than the all-season ones, even at 0°C.
What conclusions are we to draw from this?
Conducted at different temperatures, the Tyre Reviews test yet again proved just how dangerous it is to use summer tires outside of the weather conditions that they were engineered for.
The wet braking tests showed that the braking distance ensured by the summer tires starts to grow abruptly as the temperature drops below 7°C, while the all-season tires and the classic winter tires has a minimum dispersion of results in the temperature interval from 2°C to 15°C.
This again goes to show that summer tires definitely have no business being on winter roads, especially if we are to consider the huge gap between the results they demonstrated on snow, and those ensured by the other contestants.
Using all-season tires, on the other hand, is quite alright, only while purchasing them one must consider the most likely «overboard» weather conditions. Even though the all-season tires perform quite efficiently on snowy roads (and, again, keep in mind that the test involved premium-class models), using them only makes sense in the regions with milder winters.