Misaligned directional tire test

Автор: Mosautoshina

Many tires have directional V-shaped tread patterns designed to quickly divert water or slush from the contact patch. One feature of such tires is that they can be installed incorrectly (for correct installation, such tires are equipped with special markings, for example, with an arrow image, on the sidewall), and if the pattern is "pointing" upwards, not downwards, water will be displaced not outward, but to the central zone of the tread. The traction in this case will deteriorate, and to what extent the experts from the German magazine Auto Motor und Sport decided to check, who conducted tests of correctly and incorrectly installed winter tires with a directional pattern.

In addition, AMS evaluated how much worse new tires work when worn out, and tested snow chains by installing them on winter and summer tires. The tests were carried out on snow and wet asphalt in several disciplines, such as traction, braking, handling, and resistance to longitudinal and transverse aquaplaning.

As an example of directional tires, the winter Nokian Snowproof 2 were chosen, and when starting from a place and braking on rolled snow, the mounting error had an effect, but barely noticeable, but in the handling test, the car began to skid in turns due to uncontrolled slipping of the front tires, and the reason was that the tires could not cope with the resulting transverse loads. On dry asphalt, there was also no significant decrease in traction, but the noise level increased, and on wet pavement, incorrectly installed tires also quickly began to skid, and handling deteriorated seriously, while aquaplaning, as expected, started much faster (almost 10% in the longitudinal direction).

Nokian Snowproof 2 (what directional tires look like when installed correctly)

Thus, when installing directional tires, it is necessary to inspect the sidewalls, where the correct direction of rotation will be indicated. In addition, for more even wear, regular tire rotation is important, and tires with a directional pattern should only be rearranged from one side of the vehicle, from front to back and vice versa, otherwise the level of safety in rainy weather will deteriorate (it remains to add that incorrect installation of directional tires is also believed to lead to their accelerated wear, but such a test was not conducted by AMS).

The tests also showed that the wear of winter tires is very important, because when the tread depth of all tires decreases to 4 mm, the traction on snowy and wet surfaces decreases significantly, and they resist aquaplaning worse than incorrectly installed but new tires. If only two winter tires are replaced, it is recommended to install them on the rear axle (including on front-wheel drive vehicles), and the reason is that the traction of the rear tires is crucial for preventing skidding when cornering.

Summer tires also took part in the tests, and there were no surprises here: they are much more efficient than winter tires on wet asphalt, including in terms of resistance to aquaplaning, but they are not suitable for snow.

Finally, in the final part, the specialists evaluated how well snow chains work, and it turned out that when installed on winter tires, they increase traction on snow, but in combination with summer tires, the grip is still very weak. According to experts, when starting and braking, the wheels spin, and what's worse, on the axle without chains, there is no traction at all.

In general, for maximum safety in cold weather, winter tires with a sufficiently large tread depth and correct installation are needed.