FAQ Sidewall markings Tyre care Manufacturing and environmental issues Other topics Studded or non-studded tyres? Should you have a question that is not here, please send it to us here. Sidewall markings In the tyre size designation, what do 175/60 or 175/65 stand for? The first three-digit number is the cross-section width in millimetres measured at the widest point when the tyre is mounted on the measuring rim. The number after the slash is the aspect ratio, which is the relationship between the standing height of the tyre and the cross-section width as a percentage. What does the XL stand for in the size designation of a tyre? XL is the Extra Load load range. The tyre is developed for a maximum load of four units higher. For speeds over 210 km/h the actual load of V, W and Y rated tyres is reduced accordingly. (For further information, refer to the ETRTO Standard Manual 2000, p. 8.) This type of tyre is becoming increasingly popular, because the mass of fast cars has increased.' What information does the Nokian DSI wear indicator provide for the driver? The DSI driving safety indicator displays the remaining tread in numbers, which tells you when you should replace your tyres. By monitoring the tread wear, you can also get more mileage out of your tyres by rotating the positions of the tyres between the front and rear axles, which evens out the differences in tread wear between the different axles. How does one distinguish studless winter tyres from summer tyres? Winter tyres have the M S (MS, M&S or Mud&Snow) marking on the sidewall. Tyre care How long will tyres last? It is difficult to determine a specific maximum age for a tyre, since the wear and ageing of a tyre are due to several different factors. For example, a tyre will wear out 4–5 times faster in the spring than at the end of the summer. According to international practice, the maximum recommended usage life for a tyre is 6 years, and the maximum age of the tyre is 10 years. Tyres that have been manufactured a maximum of 5 years earlier may be sold as new, since tyres will retain their original characteristics for up to 5 years when stored correctly. Between seasons, tyres should be stored in a cool, dark, and dry place. Read more on the proper storage of tyres at https://www.nokiantyres.com/proper-storage. The safe minimum groove depth for winter tyres is 4 mm. We do not recommend using winter tyres (M+S) under summer conditions. Tyres must not come into contact with solvents, such as oil, petrol, or lubricants. My tyres wear more in the middle than at the sides. Do I have incorrect inflation pressures, or why does this happen? Traction tyres normally wear more in the middle than at the sides and free-rolling tyres wear more at the sides. The best way to even out the wear and to get the best possible driving results from your tyres is to rotate the positions of the tyres between the front and rear axles after every 8,000-10,000 km (5,000-6,000 miles). I mounted one of my studded tyres against the rolling direction and drove it like that through the winter. Did it damage the tyre? The tyre does not get damaged when it rolls against the specified rolling direction. However, it is recommended that you do not change the rolling direction of a studded tyre during its useful life as this may affect the grip of the studs on the tyre. To achieve the best possible cleaning and slush properties, the tyres should be mounted in their correct rolling direction. If studs work loose from studded tyres, is it possible to replace lost studs with new ones? It is not possible to replace lost studs with new ones as they cannot be fixed securely to the old stud holes. How do I know the correct inflation pressures? You will find details of the correct inflation pressures for your car in the Owner's manual, on the tyre placard on the petrol tank of your car, on the glove compartment door, on a door edge or on the side of a door. If the information cannot be found in any of these places, professional tyre repair shops and Nokian Tyres Technical Customer Service will be able to help you. May I use a solvent when washing my tyres? We recommend that you use a mild detergent, such as a car shampoo, on your tyres. Remember to rinse tyres thoroughly after washing, so that solvent residue will not remain in stud holes or between sipes. Do not direct the spray of a pressure washer on the tyre surface up close, as the high-pressure spray may damage the coord structure. Manufacturing and environmental issues What makes up the price of a tyre? Tyres are complicated technical products and tyre manufacturing requires massive investments in product development and production. The majority of the price of the tyre is because of the raw materials used and the manufacturing labour costs. How environmentally friendly are Nokian brand passenger car tyres? The environmental friendliness of our products and manufacturing processes is an essential part of our operations. Our main principle is to select the least environmentally damaging raw materials available and, consequently, Nokian Tyres plc is the first ever tyre manufacturer to receive the ISO 14001 environmental certificate. What happens to worn out tyres? There are three major areas of use for used tyres: retreading, energy and material use. Retreaded tyres are used tyres equipped with new treads. Most passenger car and delivery van tyres can be retreaded once and truck and bus tyres between two and three times. Tyre granulate can be burnt to produce energy and its energy value is equal to that of coal. Rubber granulate has hundreds of uses. The most important applications include road maintenance, noise barriers, artificial reefs, floor and wall coverings and as isolation material on new landfill sites under construction or old ones closing down. Where are Nokian brand tyres studded? The Nokian Hakkapeliitta 8, Nokian Hakkapeliitta 7, Nokian Hakkapeliitta 7 SUV, Nokian Hakkapeliitta 5, Nokian Hakkapeliitta 5 SUV, Nokian Hakkapeliitta C Van ja Nokian Hakkapeliitta C Cargo tyres are delivered to retailers studded by Nokian Tyres. Other studded tyres are supplied to order either studded or without studs. How are the stud holes made? Stud pins in the curing mould imprint the stud holes in the tread or, in the case of heavy tyres, the stud holes are drilled. Is there a manufacturing date on tyres? On all Nokian branded tyres, a four-digit-code shows the year and week when the tyre was manufactured. The manufacturing code has four digits, for example, the code 2100 means that the tyre was manufactured in week number 21 of the year 2000. Other topics Tyre's correct rolling direction. Many of Nokian Tyres' summer tyres are so-called Inside/Outside models. The tread pattern is designed so that one shoulder, with a slightly stiffer pattern, is meant to function as the outside shoulder, while the other has a more open pattern and is meant to function as the inside shoulder. In such a case, the tyre's outer sidewall will have the text 'OUTSIDE', indicating the side which should be installed as the outer side, so that the tyre will function correctly. The sidewall will also carry the tyre's placement memory with its F/R markings, which indicate front and rear axles; however, these markings have nothing to do with the tyre's rolling direction. Can I drive my non-studded winter tyres all year round? We do not recommend the use of special non-studded winter tyres like the new Nokian WR A3 and Nokian WR D3 (Central Europe) or Nokian Hakkapeliitta R (Northern Countries) throughout the year. Modern non-studded winter tyres may wear unnecessarily quickly, particularly on coarse spring roads. The wear may also be uneven due to unusual fast wear. Non-studded winter tyres should be mounted in the autumn when the ground freezes and replaced in the spring when the sun is starting to warm the roads. How do I know which tyres fit which rims? Expert tyre repair shops will assist you in selecting the correct tyres for your rims. For example, the STRO (Scandinavian Tire & Rim Organization) or the ETRTO (European Tyre and Rim Technical Organisation) tyre norm books contain fitting guidelines. You can also contact Nokian Tyres Technical Customer Support, if you have a particularly difficult question. Studded or non-studded tyres?