29. 11. 2023

What do the different tire symbols mean?

Using the 205/55 R16 91 H tl XL RFT MO MFS as an example, we will explain what the selected parameters and symbols mean.
– 205/55 R16 91 H – these are the basic parameters (dimensions) of each tire.
– tl XL RFT MO MFS – these are the special features of the tires that indicate something specific.
Width (205)
The first figure indicates the tread width in millimeters. Our tire is 205 mm.
Profile (55)
The profile is a percentage of the ratio of the tread height to the tread width. It is given as a percentage, not in millimeters. In our case, the profile of the tire is 55% of the width of 205 mm.
Construction (R)
The letter after the profile indicates the construction of the tire, which is now exclusively R for radial in passenger tires. Radial tires have inner fibers perpendicular to the direction of rotation and run from bead to bead. The R designation on a tire does not indicate diameter.
On some high-speed tires, the designation ZR is given. The letter Z indicates tires with a design allowing speeds above 240 km/h.
Tire inner diameter (16)
The inner diameter of the tire is stated in inches (1 inch = 2.54 cm) and must be the same as the rim diameter. The diameter value is followed by the speed and load index.
Load index (91)
The load index or weight index is the number corresponding to the table value in kilograms. We do not need to know the exact values in kilograms; this index is prescribed by the technical certificate.
Compared to the speed index, the load index must never be smaller. But it can be higher. Compliance with the correct index is crucial for your safety and for the certainty of compensation from the insurance company in the event of an accident.
Speed index (H)
The speed index letter corresponds to the table values in km/h. It is also shown in the large technical data sheet. The law says that the speed index of summer tires can be the same or higher. On the other hand, in the case of winter tires, it may be lower than the value on the technical certificate. Only this maximum speed should be marked in the driver’s field of vision.
Tubeless construction (tl)
The letter “tl” (tubeless) means tubeless and refers to tubeless tires. You may also see the word “tt” – it means tubetype, the type of tube used on motorcycle tires.
Reinforced tire = reinforced tire construction (XL)
The letters XL (extra load) indicate tires with increased load capacity. RF (Reinforced) has the same meaning. This designation is mainly found on pickup trucks or smaller commercial vehicles that are purpose-built for heavier loads.
Run-flat tire (RFT)
The letters RFT stand for one of several ways of referring to range tires, commonly known as run-flat tires. The run-flat technology of all manufacturers works on exactly the same principle, namely a self-supporting sidewall. The sidewall of a run-flat tire is reinforced to such an extent that it can support the weight of the car when the tire loses pressure.
In the event of a puncture or sudden loss of pressure, you can drive at a maximum speed of 80 km/h for a maximum distance of 80 km with the range tires. Tires with range technology may only be fitted to vehicles for which they are approved by the vehicle manufacturer and which have a tire pressure monitoring system, either via a sensing device inside the tire called a TMPS or via an ABS or ESP sensor.