You can easily test the condition of your tires by using tools that are found in your home. The match and coin tests are especially suitable for evaluating the condition of non-studded tires.
All of Nokian Tyres' latest products are equipped with Driving Safety Indicators. The driver can use the indicators to check the condition and safety of the tires. The indicator is located on the centre surface of the tire, and it indicates the depth of the tire's main groove in millimetres; in other words, it shows how much tread remains.
The DSI driving safety indicator displays the remaining tread in millimeters, and tells you when you should replace your tires. It is recommended that the tire be replaced once the "4" has worn away. On some tires, DSI also includes a rain drop symbol. When this has worn away, the tires' hydroplaning capabilities are no longer optimal, indicating it is time for replacement. Once the "2" has worn away, the tires are no longer safe to drive and should be replaced as soon as possible. Also by monitoring the tread wear, you can get more mileage out of your tires by rotating the positions of the tires between the front and rear axles and even different sides of your vehicle. Frequent rotations evens out the differences in tread wear rates between the different positions on the vehicle.
Testing with a match
You can measure safety by using a regular five-centimetre match, which has a 3–4-millimetre sulphur tip. The tip should disappear from sight when the match is placed into the groove. Test at several points around the tire. If the sulphur remains visible, the tread is not safe for winter driving. We recommend a minimum groove depth of 4 millimetres. The law requires 3 millimetres of tread for winter tires, and 1.6 mm for summer tires.
Examine your studded tires
If the studs are still attached, but they wobble from side to side, the grip of the tire has been substantially reduced. A stud that bends will not penetrate the ice, and it has weak grip on slush and snow. If a lot of studs have come loose – and the number of studs differs between the tires – then the grip of the tires can be dangerously weak. According to the stud legislation, the maximum allowed variation in the number of studs between the tires is 25%. Even though it is convenient to assess the safety of your tires, the results will always be slightly imprecise and unreliable – especially since drivers tend to overestimate the condition of their tires. This is why Nokian tires has developed the Driving Safety Indicator for its new tires. The indicator accurately shows the amount of remaining tread and safe kilometres.