Tyre pressure and load index of heavy-duty truck tyres
It's widely known that tyres are the parts that touch ground directly when the truck is moving, carrying the entire vehicle. The tyre itself plays a role of support and buffer depending on the inner gas state and structure.
Tyre pressure is the pressure inside heavy-duty truck tyres. Too high or too low will cause a flat tyre. Therefore, there is a relationship between tyre pressure and load. Reasonable tyre pressure is conducive to vehicle load and safety.
Secondary, it's necessary to know the performance index of tyres. Generally, there is a row of numbers and letters marking on the side of tyres, which represent size, load, type, etc. For example, 195/55 R15 85 V, 195 means the section width is 195mm.
55 refers to flatness ratio, the ratio of section height to section width. The later letter and number represent tyre type and rim diameter. Specifically, R means radial tyres which are basically used by family cars while D represents diagonal tyres which are used by low-speed trucks and construction machinery vehicles.
Then, 85 is the load index. But a load index table is needed to know the maximum weight that a heavy-duty tyre can bear. In the table, 85 corresponds to 515, that is, the maximum weight is 515kg under the standard conditions for tyres. However, trucks don't only have one tyre. Each tyre has different forces. As a result, even if the vehicle bears a tremendous weight, it's spread to several tyres with smaller weight, avoiding a flat tyre.
For example, if the weight that a vehicle with 18 tyres bears is 180 tons, load of each tyre will become much smaller. But forces of front, middle and rear wheels are different. Besides, it's not easy to have a flat tyre for heavy-duty tyres have good wear resistance and pressure resistance, elasticity and toughness.
On the other hand, bridges are loaded on piers. Each bridge has a limited load. Once it exceeds, the bridge is likely to be dangerous. Moreover, vehicles traveling on the same side all the year round can easily lead to uneven stress and loss of balance of the bridge. What's more, issues such as scanty maintenance of road at ordinary times make bridges easy to roll over.
It's very dangerous to be overloaded, but there are still a lot of people carrying overweight goods, not only destroying roads, but also risking their lives. It is not responsible for themselves and others. Therefore, small cars should be alert, keeping a certain distance after trucks. Meanwhile, it appeals that everyone must not overload and cherish life!