Tire markings
Depending on the year of manufacture, tires have different markings:
- In the old markings - for example, 185/70HR14 - the letter designation of the maximum speed (H) is in the middle.
- In the new markings - for example, 185/70R1484H - the letter designation of the maximum speed (H) is at the end. A number indicating the mileage of the tires has been added to the markings (in this case 84).
- Tyres with the TD code designation retain their driving properties even after a puncture, while tyres with the TRX code designation have a metric internal diameter. This is indicated by the number 390 in tire brands 1 95/60VR390TD or 195/60R390 91 H M+S (TRS). For other tires, the inner diameter is measured in inches.
Markings on the sidewall of the tire
1 - maximum load; 2 - tire air pressure; 3 — cord material: 4 — sidewall material; 5 - tread material; 6 - DOT Compliance Marking (US Department of Transportation); 7 — manufacturer code; 8 — tire size code; 9 — brand designation of the tire type; 10 — week of production; 11 — year of manufacture; 12 - radial; 13 - tubeless; 14 — nominal width; 15 - height to width ratio; 16 - radial; 17 — disk diameter; 18 - index or conditional number of load; 19 — maximum speed index; 20 — ECE sign (Economic Commission for Europe); 21 is the standard number.
The numbers and letters in the tire markings mean the following:
- 185, 195, 200, 205 - tire width without load in millimeters;
- 55, 60, 65, 70 - the ratio of the tire's height to its width - for example, 65:100. Accordingly, this value is lower for tires marked with the numbers 60, 55.
- R - tire type designation: radial.
- 15, 390: The inner diameter of the tire in inches or millimeters.
- Q - maximum speed of 160 km/h - speed class for regular tires marked M+S.
- S - up to 80 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 marking). Superseded by the designations V and ZR.
- V - up to 240 km/h.
- ZR - over 240 km/h.
- TD - a class of tires that maintains traction when punctured.
(The material is taken from a web resource: «Nissanbook.ru»)
Wheels - markings
The numbers and letters on the disc markings mean the following:
- 6, 6.5, 7, 167, 180, 195 - rim width in inches or millimeters (for TRX and TD modification disks).
- J - conventional designation of the side height. X - designation of deep rim.
- 15, 390, 415 - maximum disc diameter in inches or millimeters (from side to side).
- ET 19, ET 20, ET 22 – rim seating depth. This size specifies the code designation below.
- TR is the code designation for a TRX type wheel.
- TD is a code designation for wheels that retain driving performance even if the tire is punctured.
Cars can be equipped with three different types of wheels: standard deep-dish wheels, TR wheels, and TD wheels. It's important to note that not all tires are suitable for all wheels, and vice versa. A deep-wall rim should be fitted with a regular radial tyre, a TR-type rim with a TRX-type tyre, and a TD-type rim with a TD-type tyre.
Currently, most car models are equipped with all-season radial tires with a steel brake belt as standard equipment. These tires have an average 37% higher snow traction than conventional road tires previously fitted to cars. At the same time, such properties of tires as grip on wet road surfaces, rolling resistance, service life, and the ability to retain air pressure have been improved. These improvements have been achieved through changes to the tread design and the use of special rubber compounds. The described vehicles are equipped with P235/65R1 8104T or T165/90D18107M tires.
TRX type tires and wheels
The ride will be comfortable if the tire sidewalls are high and flexible, and road grip will be improved if the sidewalls are low and rigid. To achieve a compromise between these conditions, the TRX tire carcass was developed, which works equally under tension and compression. That's where the name of the tire comes from "TR" - "tension repartie" (load distribution). Therefore, this tire has a modified sidewall shape, which necessitated the creation of a new disc.
TD type tires and wheels
These tires have a strongly developed additional bead on the flange, which fits into a deep groove on the edge of the rim. This significantly improves the adhesion of the tire to the rim, preventing the tire from slipping 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 type tire remains on the front wheel for up to 30 km, on the rear wheel - up to 9 km (if it is leading). However, the speed on turns should not exceed 30 km/h, and when driving straight ahead, 60 km/h. However, even if a tire unexpectedly punctures at higher speeds, it will not be torn off the rim—even on turns. The car remains steerable and can be stopped smoothly.