It's like: a solid sponge, which will be deformed when pressed lightly, right? Although the steel pipe is hollow, if you press it hard, it won't change except your hand hurts, right?
The relationship between tire deformation and tire pressure First of all, tire pressure does directly affect tire deformation, just like a balloon. The more you blow, the greater the expansion.
However, it should be noted that when the tire pressure reaches a certain value, the influence of tire pressure change on the tire deformation range will not be so obvious.
Like: You blow a balloon. When you blow into the balloon, you see it getting bigger and bigger, almost expanding. Blow twice more, but it's not obvious, and it's not obvious.
Yanshan University has a master's thesis "Experimental Study on Rolling Radius of Automobile Tires".
Under certain load conditions, the settlement of the same tire under different tire pressures is tested, that is, the deformation amplitude test.
When the tire pressure is 1bar (that is, 1 kg), that is, when the tire is obviously out of pressure, the settlement is 18.04mm, and the deformation is obvious, and it is flat over there.
The tire pressures of 2 bar, 2.5 bar and 3 bar are 6. 12 mm, 2.96 mm and 0.84 mm respectively.
You don't have to remember numbers, that is, the difference is getting smaller and smaller, and it is relatively difficult to distinguish with the naked eye.
You see, when you hit 1 kg (1bar), it is obviously flat over there; 2 kg, 2.50 kg, 3.0 kg, you see, they are all the same.
Pacific Auto Network has also done an experiment on tire deformation under different tire pressures. The results show that the tire pressure does not change obviously in the range of 2.0 bar to 3.0 bar.
Lao shifu is not kicking. Are you angry? Does this tire feel good?
2.0bar to 3.0bar is basically useless.
When the tire pressure is lower than 1.3bar, the tire can be observed visually, and the deformation of the tire can be seen by the eyes, which is what we call "the tire is flat" in vernacular Chinese.
According to the test conclusion, although insufficient tire pressure does deflate the tire, it is still difficult to accurately judge the tire pressure by visual inspection when the tire deformation is not obvious, and it is still necessary to measure it with the help of a tire pressure gauge.
The range of tire deformation is related to the stiffness and load of tire wall. In addition, in addition to tire pressure, sidewall stiffness and load will also affect the deformation amplitude of sidewall.
Some tires look flat, not necessarily because the tire pressure is insufficient, but because the tire wall is less rigid or bears more weight.
But as long as the tire pressure is within the standard range, you don't have to worry about this problem. It depends on the tire pressure, not the shape.
Generally speaking, the tires of family cars pay more attention to comfort, and the tire wall is more elastic and less rigid. Some tires may look flat under standard tire pressure.
Think about it: Is latex mattress softer? Still elastic? When you lie down, you will slowly sink in. It's actually much more comfortable than a regular mattress, isn't it?
I won't talk about it. You were lying down and fell through this mattress, right? Not exactly.
The tires of family cars usually look fatter and thicker, that is, the flat rate is higher.
For example, the flat rate of the original Audi 235mm tire is 60%, and the flat rate of the Ford Focus ST tire with low performance is only 40%.
There is a paper "Evaluation and Analysis of Vehicle Ride Comfort" in Heilongjiang Science and Technology Information magazine, which says that the cornering stiffness of a tire with 50% flatness ratio will be 70% higher than that of a tire with 80% flatness ratio.
In other words, most of the tires used for family cars are called "fat tires", and the tire wall hardness is relatively low and looks flat.
A puncture has a special function, and the tire wall is hard, so it is not easy to have a flat tire. On the contrary, some luxury brands are equipped with run-flat tires, which are called "flat tires" in the local dialect.
For example, in 2020, the tires of BMW 3 Series and Cadillac CT4 will have much greater sidewall stiffness. Even if the tire pressure is insufficient, it is difficult to be crushed, and it even looks like nothing.
There is a paper in Tire Industry magazine, which mentioned "Discussion on the Forming Process of Self-supporting Run-flat Tire".
Compared with ordinary tires, run-flat tires have greater sidewall thickness and strength.
Bridgestone official website: We looked it up and there was an introduction.
Using RFT (run without air technology) technology, even if the tire is punctured, the sidewall reinforced rubber can still support the weight of the car body. That is: you can drive without oil.
The front of most family cars is relatively heavy, and the front wheels will appear relatively flat. Let's say one last. Many friends actually observed that under normal tire pressure, the front wheel usually looks a little more flat than the rear wheel.
Because most cars and family cars have engines in the front, and the engines are not put in the back. If there is weight in front, it will be heavier.
The third edition of Automobile Structure, edited by Jilin University and published by Machinery Industry Press, was mentioned above.
According to the position and drive form of the engine, the automobile can be divided into various forms, such as front drive, front rear drive, center rear drive, rear rear drive, etc., but the front drive is the popular layout form of most automobiles now.
Family cars are basically with the engine in front and the driving wheels in front. The powertrain and transmission system are both at the front of the car, so the front wheel will have greater bearing capacity.
Ford Focus was tested by a motor vehicle testing agency in Beijing.
The weight ratio of its front and rear axle is about 60 in the front and 40 in the rear. Among them, the load of the front axle is 872kg, and the load of the rear axle is 565kg, which is 307kg and more than 600 kg.
What is the concept of more than 600 kilograms? The weight of four or five adults, right?
Excessive tire pressure will affect the performance and service life of tires. If you see a flat tire, inflate it blindly until it bulges, and the tire pressure may exceed the standard value. Far from solving the problem of puncture, it may be harmful.
It's like: the chef cooks and puts some salt in it. Everyone thinks it's fresh and delicious, right? "Gung, gung, gung, gung, gung, gung, gung, gung, gung.
Wuhan University of Technology has a master's thesis, "Design of Tire Pressure Monitoring System (TPMS)".
Too high tire pressure will aggravate wear, make riding comfort worse, and reduce the righting performance. When encountering the impact of obstacles during driving, tires are more likely to break.
Very easy to understand. It's just a balloon. When you blow it big enough, poke it with a toothpick and it will break with a bang.
So how should I cheer up? The standard value of tire pressure is subject to the recommendation of the car factory, which can be found in the manual and the nameplate of the car body.
Most of the family cars we use are usually between 2.3 and 2.5 bar, which is called "kg" in Lao shifu dialect.
Blindly inflating may damage the tires. Generally speaking, tires look a little flat. Maybe it's not enough tire pressure, maybe it's just a psychological effect. As long as the tire pressure measured by the tire pressure gauge is normal, don't care.
If the tire looks flat, it may be better not to do it, which is not worth the candle.