The tyre lettering can be located on the inner side of tyre. Certain labels may only be found on one side of the tyre, e.g. tyre identification num- ber and manufacturing date. a) The TIN is the tyre serial number. Tyre load The load index indicates the maximum load ca- pacity of an individual tyre in kilograms (kg, tyre load). Any further numbers and letters are internal co- des used by the tyre manufacturer or country- specific codes. Examples:
88 91 92 93 95 97 99 100 101 102 103 104 105 560 kg 615 kg 630 kg 650 kg 690 kg 730 kg 775 kg 800 kg 825 kg 850 kg 875 kg 900 kg 925 kg Low-profile tyres Low-profile tyres have a wider tread surface, larger rim diameter and lower side walls than conventional wheel/tyre combinations. → in Using of Wheels and Tyres on page 188. Low- profile tyres can improve the vehicle's handling and precision. They may however result in a less comfortable ride on uneven road surfaces and tracks. Tyres with directional tread pattern An arrow on the tyre sidewall indicates the direc- tion of rotation on tyres with directional tread.
Therefore, the tyres must be fitted in accordance with the marked rotation direction to ensure that the tyres have the best road adhesion, prevent the wheels from slipping, and reduce the rolling noise and wear rate of the tyres. Speed index. The speed index indicates the maximum permit- ted speed that may be driven with the tyre. If, however, the tyre is fitted in the opposite di- rection to the tread pattern, you must take more care when driving, especially on slippery roads. The tyres must be replaced as quickly as possible or be fitted with the tread in the correct direc- tion. P Q R S T U H V Z W Y Max. 150 km/h Max. 160 km/h Max. 170 km/h Max. 180 km/h Max. 190 km/h Max. 200 km/h Max.
210 km/h Max. 240 km/h above 240 km/h Max. 270 km/h Max. 300 km/h Asymmetrical tyres Asymmetrical tyres take into account the differ- ing behaviour of the inner and outer areas of the tread pattern. The sidewalls of asymmetrical tyres are marked to indicate “inside” or “out- side”, to ensure that the tyre has the best road adhesion, prevent the wheel from slipping and reduce the rolling noise and wear rate of the tyres. Some tyre manufacturers use the letter “ZR” to indicate a tyre with a maximum permissible speed above 240 km/h. 182.5C1.TRO.74 Wheels and tyres 195 → Fig. 150 Tyre lettering (example) Meaning 20 SIDEWALL 1 PLY RAYON Details of the tyre carcass components:
1 ply of rayon (artificial silk). TREAD 4 PLIES 1 RAYON + 2 STEEL + 1 NYLON Details of the tread components: In the example there are 4 plies under the tread surface: 1 ply of rayon (artificial silk), 2 steel belt plies and 1 nylon ply.