The information for the user about the tyre size is on the sidewall . Standardisation of tyre markings is in accordance with the European regulations of ECE-R 30. The inscription on the sidewall of a tyre indicates the key parameters of the product.
195 - tyre width. The first value in the tyre size designation is expressed in millimetres. The width of a tyre on the marking increases every 10 mm, so we can find models with dimensions 175/65R 14, 185/65 R14 or 205/55 R16. In fact, the width of tyres differs slightly from the values used in the markings, especially with different manufacturers. For example, the number 195 means that the tyre width is 195 mm. This length indicates the distance between the outermost sidewall point on the outer wall and the outermost point on the inner sidewall after the tyre has been fitted on a rim with appropriate width. The dimensions described here are called the cross section width of a tyre.
60 - aspect ratio. The next value in the tyre size is an indicator of the profile of the model. This symbol informs the user about the percentage of profile height to tyre width. In this way we learn how much of the tyre width is occupied by the tyre profile. For example, for a tyre size 195/60 R15, the profile is 65, which indicates 65% of the tyre width. 65% of 195 mm is 117 mm. Lower tyre sidewall values are characteristic of low profile tyres, which are usually marked with numbers 50, 45 and 40. High profile tyres, on the other hand, usually do not have profile height information, e.g. for 165R13 the profile is 80.
R - means a tyre of radial construction. This symbol is used for radial tyres with a body based on layers of radial spreading fibres at an angle of 90 degrees across the tyres. The use of the R mark on a 195/60 R15 size tyre informs the user that the model has a radial construction consisting of carcass layers running radially from the centre of the wheel. Radial tyres are the most popular product among tyres and account for 98% of worldwide sales.
15 - the value by which we can find out what diameter of the rim is recommended when mounting a tyre. This parameter is specified in inches.