That would be an example of a relatively low height-to-width ratio: 235/35 ZR 19. Its minimization goes hand in hand with an ever-increasing rim diameter. The laughing third is the disc brake, which can also increase in diameter, but usually only does so extensively at the front. However, the limit is the diameter of the standard tires.

In this chapter, however, we are not concerned with the numbers in the tire designation, but with the letters.This is very easy with the 'R', it stands for radial tires. The additional letter, here in front of it, sometimes at the very end, represents the permitted speed. By the way, this is extremely important.

For example, tire tests were carried out and this speed was exceeded by 20 km/h, for example. In some of these tests, tires burst already after just 10 minutes. Critics say the tests on the roller are not representative because the wheel would always put the same piece of roller under its tires, which would mean more heat, for example. After all, the rollers have now become huge drums in which the wheels roll on the inside.

Of course, you would never have a tire fitted below the permissible speed of the vehicle and, in the case of winter tires with a lower permissible maximum speed, you would always attach the associated sticker in a clearly visible place in the cockpit or directly on the speedometer. This would also protect you against any surprises when it comes to insurance cover.

The basic code for the speeds is easy to remember. You start with 'F' and 80 km/h and count up by 10 km/h with each letter. Only the many exceptions are complicated. This starts with the 'H', which has to be left out, the 'I' and the 'O' too. So it goes cheerfully up to the 'U' and 200 km/h. Now, unscheduled, the 'H' for 210 km/h is added after all, a tribute to the past when the 'H' stood for 'high speed' and 210 km/h.

It continued with 'Very high speed' and 240 km/h. Here you can see where the highest imaginable speeds used to begin. So today there is still a gap between 210 and 240 km/h, the latter marked with a 'V'. And then the letters gradually ran out.

For the sake of simplicity, the jumps of 30 have been retained and 270 km/h marked with 'W' and 300 km/h with 'Y'. The 'X' is missing from the table, as is the 'I'. And because there are still much faster vehicles, the designation 'ZR' means that vehicle and tire manufacturers should agree on. There is usually only one make of tire for such vehicles.