Two types of the tyre size designation can be found on a tyre sidewall, a tyre width expressed in mm and the tyre width expressed in inches.
1. The tyre width expressed in mm
All tyres for the commercial vehicles must be marked with a
Service Description located after the size designation (European regulation ECE-R54). The service description consists of
load index and
speed rating (e.g. 156/150 L).
Listed below are a few examples of the truck/bus tyre size designations.
Here is an example of the tyre size designation for commonly used truck tyre:
Tyre size designation can be found on the tyre's sidewall with information about tyre:
- » Tyre width in inches or mm
- » Aspect ratio – ratio of height to width
- » Construction type
- » Speed index - Maximum allowed speed
- » Rim diameter
- » Load index - Maximum load capacity
1. Radial motorcycle tyres - designation in mm
Metric tyre size designation is the most common designation system. For example:
During the hot summer days, when you drive, the temperature of tyres increases faster, consequently, the heated air inside the tyres expands and its pressure rises quickly, which can lead to tyre blowout with disastrous consequences. A tyre blowout is a rapid loss of inflation pressure of a pneumatic tyre leading to an explosion.
Recommended car tyre pressure in manufacturers manuals are for the cold tyres. It means that the vehicle hasn't been driven for a several hours before the measurement of pressure. Ideal time for this is during the night or early in the morning, before going to work, or when the temperature of the tyres equals the outside air temperature. It also means that normal ambient temperature of tyres is about +20 degrees °C.