Tire marking
Depending on the year of manufacture, tires have different markings:
- In the old marking - for example, 185 / 70HR14 - the letter designation of the maximum speed H is in the middle.
- In the new marking - for example, 185 / 70R1484H - the letter designation of the maximum speed (H) stands at the end. A number has been added to the marking indicating tire mileage (in this case 84).
- Tires coded TD have punctured performance while tires coded TRX have a metric inside diameter. It is he who is indicated by the number 390 in the brand of tires 195 / 60VR390TD or 195 / 60R390 91 N M + S (TRS).
For the rest, the inner diameter of the tires is measured in inches.
Tire side marking
1 - maximum load; 2 - air pressure in the tire; 3 - cord material: 4 - sidewall material; 5 - tread material; 6 - marking of compliance with DOT standards (US Department of Transportation); 7 - manufacturer's code; 8 - tire size code; 9 - company designation of the type of tire; 10 - manufacturing week; 11 - year of manufacture; 12 - radial; 13 - tubeless; 14 - nominal width; 15 - the ratio of height to width; 16 - radial; 17 - disk diameter; 18 - index or conditional load number; 19 - index of maximum speed; 20 - ECE mark (Economic Commission for Europe); 21 is the number of the standard.
The numbers and letters in the tire marking mean the following:
- 185, 195U 200, 205 - tire width without load in millimeters;
- 55, 60, 65, 70 - the ratio of the height of the tire to its width - for example, 65.100. Accordingly, this value is lower for tires marked with the numbers 60, 55;
- R - tire device designation: radial.
- 15, 390 - inner diameter of the tire in inches or millimeters;
- Q - speed limit 160 km / h - speed class for conventional tires marked M + S;
- S - up to 180 km/h;
- T - up to 190 km / h - high-speed tires M + S;
- H - up to 210 km / h;
- VR - over 210 km/h (old but still used markings). Superseded by the designations V and ZR;
- V - up to 240 km / h;
- ZR - over 240 km / h;
- TD is a class of tire that retains traction when punctured.
Disks - marking
The numbers and letters of the disc markings indicate the following:
- 6, 6.5, 7, 167, 180, 195 - rim width in inches or millimeters (for TRX and TD rims);
- J - symbol board height;
- X - deep rim designation;
- 15, 390, 415 - maximum disc diameter in inches or millimeters (side to side);
- ET 19, ET 20, 6T 22 - rim fit depth. This dimension specifies the code below;
- TR - code designation of a TRX type wheel;
- TD is a code designation for wheels that maintain driving performance during a tire puncture.
As you can see from the previous section, there are three different types of rims that can be fitted to vehicles: conventional deep rims, TR rims and D rims. You should be aware that not all tires are suitable for all rims, and vice versa. A deep rim rim should be fitted with a regular radial tire, an R rim with a TRX tyre, and a D rim with a TD tire.
Today, most car models are equipped with all-season radial tires with steel belt as standard equipment. These tires have an average of 37% more grip on snow compared to conventional road tires previously fitted to vehicles. At the same time, such tire properties as grip on wet road surfaces, rolling resistance, service life, and the ability to hold air pressure have been improved. These improvements are achieved through changes in the design of the tread and the use of special rubber compounds.
Tires and wheels type TRX
The ride will be comfortable if the sidewalls of the tires are high and elastic, and traction is improved if the sidewalls are low and stiff. In order to achieve a compromise between these conditions, the TRX tire carcass was developed, which works evenly in tension and compression. Hence the tire's name «TR» - «tension repartie» (load distribution. Therefore, this tire had to change the shape of the beads, and this led to the need to create a new disk.
Tires and wheels type TD
These tires have a highly developed additional bead on the flange that fits into a deep groove on the edge of the rim. Thus, the adhesion of the tire to the rim is significantly improved, so that the tire does not slip off the rim in the event of a puncture.
Even with a punctured tire, the car can be safely driven out of the danger zone. A punctured TD tire is held on the front wheel for up to 30 km, on the rear wheel for up to 9 km (if it is leading). However, cornering speeds must not exceed 30 km/h and 60 km/h in straight lines. However, even in the event of an unexpected tire puncture at a higher speed, it does not tear off the rim - even when cornering. The vehicle remains in control and can be smoothly brought to a stop.