What is the pressure in the wheel of the truck. Dependence of tire pressure on climatic and road conditions

Useful information

Truck tire pressure affects a large number of characteristics of the truck... This can be the transfer of forces during acceleration, and ride comfort, and optimal mileage, and many other factors.

Truck tire pressure affects a large number of characteristics of the truck itself. This can be the transfer of forces during acceleration, and ride comfort, and optimal mileage, and many other factors. If the tire pressure is too high or too low, then this increases the likelihood of dangerous situations on the road.

Pressure too low entails a strong compression of the carcass, which leads to overheating of the truck tire, increased rolling resistance, uneven wear and reduced tire life. Suppose the tire pressure is 30% below the norm, this increases fuel consumption by 10%, and what is important, doubles the tire wear rate. The braking efficiency is reduced by 15%. Also, low pressure leads to "fatigue" of the frame, and often, to its sudden destruction.

If tire pressure above normalthen this reduces the optimal mileage. Exceeding the norms of pressure not only leads to a decrease in the life of the tires, but also the tires wear out unevenly, especially on the driving axles.

Normal pressure in truck tires significantly reduces fuel costs, and also contributes to the safety of the carcass for its restoration in the future, which leads to savings of about 30-50% of the cost of buying a new tire.

Tire pressure from manufacturers

Mainly truck manufacturers indicate two tire pressures: one for full load, the other for normal vehicle load. If the manufacturer has indicated only one value, then for a full load of the car, you need to inflate the tires by 0.3-0.5 atmospheres. It is advisable to do the same procedure before going to long trip on the freeway.

Ideally, the pressure inside a truck tire should be commensurate with the load the tire is subjected to. The pressure is checked at least twice a week in truck tiresoh. You need to check cold tires, i.e. before the trip. Because after a ride, the pressure in truck tires can be up to 20% higher, this is due to the design features of the tire. So, remember: the pressure is not measured in heated tires.

All tires must have valve capsbecause these caps function as an additional valve that holds pressure. If the tires in a truck are flat or not sufficiently inflated, then you should not drive such a car. The tires in the truck should be inflated to the pressure level specified by the manufacturer for cold tires.

Pressure standards for truck tires

Tire size	Model	Execution	Tread pattern type	Ply rate	Rim designation	Tire dimensions, mm		Int. pressure, kPa	Max. speed
						outdoor Diameter	profile width	index	kN		index	km / h
5.50-16	F-122	chamber	high cross-country ability	8	4.00E. 4.50E 4.00E	690	154/165 154/165	102		400	A5	25
5.00-10	B-19A	chamber	universal	6	4.00E	507	140	70	3,3	294	A6	30
165-13 (6,45-13)	Bel-38	chamber	universal	4	114J (41 / 2J) 127J (5J)	610	167/172	78	4.37	170	IN	50
Promising models
28L26	Bel-22	tubeless	high cross-country ability	12	DW25A	1577	713		49,2	160	A8	40
18.4R42	Bel-49	chamber	high cross-country ability	10	W16A	1850	467	148	13,24	160	A8	40
18,4-38	Bel-21	chamber	high cross-country ability	10	W16L	1750	467		29,00	180	A8	40
18,4-34	Bel-18	chamber	high cross-country ability	8	W16L DW15L, DW16	1650	467/457,	141	25,65	140	A6	30
16.0-20	F-64GL	chamber	high cross-country ability	14	DW-13	1075	405		36,7	350	A6	30
13.GR20	FBel-334	chamber	high cross-country ability	6	W12	1060	345	120	13.74	160	A8	40
13,0/75-16	FBel-340	chamber	universal	8	W11 W8,8.00V	900	336		18,64	240	A6	30
12.4L-16	FBel-160	chamber	high cross-country ability	8	W11 W10. W8	930	327		10.64	220	A6	30
10,0/75-15,3	Bel-251	chamber	universal	8	9.00-15,3	760	264		13,05	420	A6	30
6.50/80-10	FBel-263	chamber	universal	2	5.50V	507	165	76	0,4	230	G	90

A truck is a source of income, so to speak, a breadwinner. But if tire pressure is not kept within acceptable limits, it can become a source of losses. A negligent attitude towards this operational parameter threatens not only an accident. This includes fuel consumption, repair costs, and the purchase of new skates.

Why is it important to monitor blood pressure?

Incorrect tire pressure is the cause of the following consequences of vehicle operation:

Reduced tire life.
Fuel consumption increases.
Undercarriage parts wear out.
The risk of becoming a participant in an accident increases.
The load on all components (frame, body, cab, engine, etc.) increases.

Maintaining the pressure in the tires of a truck is the responsibility of the driver, and the control of performance is the responsibility of the mechanic, expert, business owner.

Where to find out how much pressure should be?

The standard pressure indicators are indicated in the table contained in the technical documentation for the machine. But if the care and operation manual is lost or become unusable, you can peep the information in the table on a metal plate attached to the cab body in the doorway, like a Gazelle. But even then it is necessary to take into account a number of factors affecting the degree of tire inflation.

What pressure should a cargo Gazelle have?

For most modifications of cargo Gazelles, the manual says that the tire pressure must be maintained at 2.9 atmospheres. However, the manufacturer does not take into account that this parameter may differ depending on operational features:

In what mode the truck is most often used (loaded or empty).
Tire model. Each manufacturer specifies the maximum allowable tire pressure, ensuring that it does not explode while the truck is moving.

All drivers have their own calculation system. Most of them, moving most often empty or half empty, pump 2.9 atm., As required by the manufacturer. The pressure in the tires of the cargo Gazelle, which is constantly operated at full load, is raised to 3.5-4.0 atm. Such a system is suitable not only for the Gazelle, but also for the tires of other trucks.

Why is the pressure in the tires of trucks overstated?

Professional car drivers aim to keep the car in good order. In order for the roll to be easier, and the wear of the rubber is less, they overestimate the pressure, making it 0.5 atm. higher than official truck tire pressures. At the same time, driving becomes less comfortable, vibration and shaking are felt more strongly, especially when the car is driving empty.

Air density control system in slopes of a truck

There are permissible deviations in pressure gauge readings associated with the following factors:

Decrease in air compression ratio over time. Deviations of 0.3-0.4 atm. from the data in the table is considered normal if the last measurement was made a month ago.
If the control is carried out immediately after the end of the trip, the pressure gauge reading will be 20% higher than the standard value.

Experienced drivers say: Not only the manometers are lying, but also the sensors provided by the car manufacturer. While driving, the rubber heats up, and the air inside the cylinder also. As a result, the sensor indicates that the wheel is over-pumped. But as soon as the car stops, the sensor will show normal data, as soon as the temperature returns to normal.

Wheel pumping should be monitored every two weeks, at least. Otherwise, you can miss the moment. The tire will start to wear out quickly, the car will be less controlled, and fuel consumption will increase.

Dependence of pressure and radius

Summary tables of permissible pressure gauge readings include a list of tires of various profiles. The pressure also varies. So, if we compare the radius of 17.5 and, say, 22.5, then in the latter case the pressure will be higher. Moreover, the difference will be very significant. For a radius of 17.5, the recommended values \u200b\u200bare:

before - up to 5.4 atm.;
back - up to 6.0.

If the tire is 22.5, then it will be 5.0 / 6.0 atm. respectively. But these figures correspond to the full load of the machine.

Visual signs of mismatch

During the operation of the car, the rubber should wear out evenly. One-sided wear has nothing to do with it, most likely this is evidence of an incorrectly set camber-convergence. But if the tire has wear in the center of the tread, then you are driving on inflated wheels.

Reverse situation with insufficient pumping. In this case, the wear is visible from both sides of the center, and is the same. In any case, it makes sense to think, rectify the situation and watch how the tread wears off. Indirect symptoms are increased consumption fuel, the severity of the stroke, shaking, vibration. To always be able to control the situation, you need to carry a pressure gauge (mechanical or electronic) with you.

Typically, tire manufacturers indicate recommended tire pressures for "normal" driving conditions. In practice, we often see a slightly different picture. If a car is loaded with luggage and four passengers, what pressure should the tire be? IN european cars on the back of the gas tank cover, you can find a table indicating how much to increase the tire pressure in one case or another. With trucks, everything is much more complicated. The most common truck consists of a tractor and a semi-trailer, the weight of this coupling is approximately 14.5 tons, and there are 12 tires in this coupling. Truck tire manufacturers recommend the following tire pressures:

315/70 R22.5 on the steering axle of the tractor 8.5 atmospheres (861.3 kPa)
315/70 R22.5 on the driving axle of the tractor (twin wheels) 7.5 atmospheres (759.8 kPa)
385/65 R22.5 on a three-axle semi-trailer 9.0 atmospheres (911.7 kPa)

If the semi-trailer was loaded with 20 tons of cargo and the hitch with the cargo already weighs 34.5 tons. What should be the tire pressure in this case? Let's try to find out.

Tire energy loss can be defined as the dissipated energy (heat) generated by the rotation of the wheel when moving one unit of travel. Based on the simplest physical principles (energy conservation law), the energy loss $ (R) $ can be written as:

$ (R \u003d \\ dfrac ((\\ text (Energy entering the tire - Energy leaving the bus))) (\\ text (Speed)) \u003d \\ dfrac (\\ text (Energy loss in the tire)) (\\ text (Speed )) \\ dfrac (W) (m / s)) $

$ (1) \\ qquad $

The unit of energy loss $ (R) $ is watts per meter per second: $ (\\ dfrac (W) (m / s)) $, which is equivalent to one Newton $ (H) $. Although the unit of measure for energy loss $ (R) $ is Newton, the tire spinning energy loss does not represent "force" but represents energy per unit distance. In general, the concepts of rotational energy loss, rolling loss and rolling friction are considered equivalent and are often used interchangeably. Energy loss in a tire includes the loss, aerodynamic dragas well as friction between the tire and the road surface. Hysteresis losses are the main component and account for about 90-95% of the total bus energy loss.

Energy loss or rolling friction is one of the most important properties of a tire because of its practical application... Researchers and engineers have been studying this issue for nearly three decades. Some of the most important studies include studies on tire materials, tire manufacturing methods, rolling friction and fuel consumption, and road-vehicle interaction.

Fuel consumption and tire energy loss for all types of vehicles are becoming increasingly important issues due to negative environmental effects (air pollution and global warming) and economic costs (high fuel costs).

In the tire industry, in turn, tires have been developed that allow efficient fuel consumption by reducing the energy loss in the tires. Tire load and pressure, vehicle speed, number of stops and vehicle design (aerodynamic shape) are parameters that affect tire energy loss. The property of the road surface is an external factor and also has a significant impact on fuel consumption.

This article examines the effect of tire load $ (W) $ and tire pressure $ (p) $ on energy loss, which affects fuel consumption.
Also discussed in detail the possible combinations of tire load and pressure depending on fuel consumption through changes in energy loss in the tire $ (R) $.

Tire control parameters and power loss

Tire load and tire pressure are two controllable parameters (which the driver can change) to control energy loss. Rolling friction changes when these parameters change. The lower the rolling friction, the more efficiently the fuel is used; slightly lower fuel consumption. It obviously follows from the basic physical principles that as the load on the tire $ (W) $ increases, the rolling friction $ (R) $ increases. On the contrary, with increasing pressure $ (p) $, the energy loss $ (R) $ decreases. But these are just qualitative relationships that are very useless for quantitative analysis. For the subsequent quantitative analysis, it is worth first of all to determine the exact quantitative relationships between the energy loss $ (R) $ and the controlled parameters $ (p) $ and $ (W) $.

Using standard load conditions and tire pressures for truck tires as starting points, the relative values \u200b\u200bof energy loss will be calculated for specific overload conditions, typically + 10% to + 100% of the recommended load at various tire pressures. These overload and pressure conditions are similar to real conditions when moving a vehicle. When a central tire inflation system is installed on a vehicle, the driver gains control over these parameters (tire load and tire pressure are displayed on the monitor in the driver's cab). Thus, the influence of these system parameters on the energy loss in the tires is considered from the point of view of control vehicle... Here we look at the increase in fuel consumption as a function of tire load. We will also suggest a fairly simple method for optimizing fuel use by changing the control variables: tire load and tire pressure.

Measurement of quantitative ratios. Relation between energy loss $ (R) $ and load $ (W) $

Using the energy balance method, it is possible to derive a basic equation describing the ratio of energy loss $ (R) $ depending on the load on the tire $ (W) $ at a constant tire pressure $ (p) $:

$ (R \u003d (h \\ cdot d \\ cdot \\ dfrac (w) (A)) \\ cdot W) $

$ (2) \\ qquad $

where $ (h) $ is the hysteresis relation, $ (d) $ is the deformation of the tire, $ (w) $ is the width of the tire track, $ (A) $ is the area of \u200b\u200bthe tire track, $ (W) $ is the load level on the tire. Various studies have shown that about 95% of the power loss can be explained by bus hysteresis. Energy loss $ (R) $ values \u200b\u200bfor three typical sizes passenger car tires size P195 / 75R14 and radial medium truck tire 11R22.5, at three different load values \u200b\u200bat constant tire pressure $ (p) $ were measured and shown in the graph. All relationships between $ (R) $ and $ (W) $ turned out to be linear; a typical graph is shown in Figure 1.

Figure: 1: Rolling Resistance (Tire Energy Loss $ (R) $) and Load for Car and Truck Tires.
Both quantities are measured in Newtons $ (N) $.

This result can be simplified as follows:

$ (R \u003d C_1 \\ cdot W) $

$ (3) \\ qquad $

where $ (C_1 \u003d \\ dfrac ((h \\ cdot d \\ cdot w)) (A)) $ is a constant or slope of a linear function. The average tilt angle (coefficient $ (C_1) $) is 0.010 for a truck and 0.0078 for the car. It is known that the deformation of the tire $ (d) $ increases with the level of load on the tire $ (W) $, but at the same time the parameters of the tire track $ (w) $ and $ (A) $ change simultaneously so that the ratio $ (\\ The values \u200b\u200bof $ (h) $ for these observations turned out to be independent of the load level on the tire $ (W) $. From which we can conclude that the power loss of the $ (R) $ bus is directly proportional to the load on the $ (W) $ bus (see).

Relationship between energy loss $ (R) $ and tire pressure $ (p) $

Although it is clear from basic physical principles that energy loss $ (R) $ and tire pressure $ (p) $ are inversely proportional, the exact relationship between the two is not known. The general equation can be written as:

$ (R \u003d C_2 \\ cdot \\ dfrac (1) (p ^ x)) $

$ (4) \\ qquad $

where $ (C_2) $ is a constant that includes the values \u200b\u200b$ (h) $ and $ (W) $. The exponent $ (x) $ for the pressure $ (p) $ must be found to obtain an accurate quantitative relationship between the energy loss $ (R) $ and the tire pressure $ (p) $. This can be done in two ways: direct experimental and using regression. Both methods are described below.

Experimental method — The data for energy loss $ (R) $ for several types of passenger tires (P175 / 80R13, P195 / 75R14, P205 / 75R15 and P225 / 60R15) and several truck tires (11R22.5 and 295 / 75R22.5) were obtained as a function, depending on the pressure level in the tire at a fixed load on the tire. Graphs of the dependence of energy loss $ (R) $ on the level of pressure in the tire $ (p) $ were constructed and using these graphs a quantitative estimate of the exponent $ (x) $ from. The results are presented in.

Table 1: Exponent $ (x) $ at tire pressure for passenger car and truck tires

Tire dimensions		Degree $ (x) $
P175 / 80R13		0.5237
P205 / 75R14		0.5140
P205 / 75R15		0.4902
295 / 75R22.5		0.4968
295 / 75R22.5		0.5326

As can be seen from the measurement results, the average value of the exponent $ (x) $ of is about $ (0.5) $. Typical plot of energy loss versus tire pressure for passenger car (P195 / 75R14) and truck (295 / 75R22.5) presented on

Figure: 2: Dependence of energy loss $ (R) $ (measured in Newtons $ (N) $) and tire pressure $ (p) $ (measured in kilopascals $ (kPa) $)

Regression analysis — does not explicitly contain the pressure variable $ (p) $. As a result, it can be modified through the dependence of the tire deformation $ (d) $ on the pressure level in the tire $ (p) $. An equation can be obtained empirically for the dependence of the tire track area $ (A) $ on the tire deformation $ (d) $, tire radius $ (r) $ and tire profile width $ (s) $:

Having determined the pressure-corrected spring stiffness coefficient $ (K) $ as $ (K \u003d \\ dfrac (W) (d \\ cdot p)) $, the tire deformation $ (d) $ can be represented as:

Table 2: The dependence of the change in rolling friction on the load on the tires

Tire dimensions	$ (W_1) $ in Newtons	$ (p_1) $ in kilopascals	$ (R_1) $ in Newtons	Magnification $ (W) $%	Magnification $ (R) $%
	Passenger tires
P175 / 80R13	2736	207	36	+33%	+31%
P195 / 75R14	3238	207	28.6	+33%	+30%
P205 / 75R15	3705	207	42.2	+33%	+33%
P225 / 60R15	3678	207	33.9	+33%	+34%
	Truck tires
11R22.5	17700	586	185.1	+17%	+16%
295 / 75R22.5	12620	828	81.3	+200%	+195%
295 / 75R22.5	6310	483	44.2	+300%	+307%

results

Quantitative relationships. Two equations and:

$ (R \u003d C_1 \\ cdot W) $

$ (3) \\ qquad $

$ (R \u003d C_2 \\ cdot \\ dfrac (1) (p ^ (0.5))) $

$ (11) \\ qquad $

are basic for determining the quantitative relationship between the energy loss $ (R) $ parameters of the load on the tire $ (W) $ and the pressure in the tire $ (p) $. These equations are used to further discuss the change in energy loss during tire overload and how excess tire pressure affects fuel consumption.

Simple calculations and detailed analysis

It was found experimentally that the energy loss $ (R) $ linearly depends on the load on the tire $ (W) $ with an increase in $ (W) $ up to 70% for most of the tires that were considered. For one of the truck tires, the linear relationship remained until the load increased to 300%. The relative increase in the load on the tire and the corresponding percentage increase we will use energy losses in the subsequent analysis. The relationship between the percentage increase in energy loss and the percentage increase in tire load for all types of tires under consideration is shown.

Figure: 3: Percentage increase in power loss $ (\\ text (Increase in) R \\ text (,%)) $ as a function of the percentage increase in bus load $ (\\ text (Increase in Load) W \\ text (,%)) $

The linear function graph shown on corresponds to the equation:

$ (Y \u003d 1.0154 \\ cdot X - 1.8735) $

$ (12) \\ qquad $

where the correlation coefficient $ (R ^ 2 \u003d 0.9987) $ indicates a linear relationship. The free constant is approximately $ (+ 1.87 \\ text (%)) $ and can be interpreted as a measure of the tire weight. So the weight of the P195 / 75R14 tire turns out to be 62 Newtons, which roughly corresponds to reality.

As mentioned above, the linear relationship between energy loss $ (R) $ and tire load $ (W) $ is most likely common to all types of tires. Simple calculations of energy loss $ (R) $ for various loads and pressure level for an 11R22.5 truck tire are described below.

$ (W_1 \u003d 17700 H) $, $ (p_1 \u003d 580 \\, \\ text (kPa)) $, $ (R_1 \u003d 185 H) $.

The relative percentage increase in energy loss for some congestion levels was presented earlier in. For example, a 70% increase in bus load corresponds to a 70% increase in energy loss, i.e. $ (1.7W_1) $ matches $ (1.7R_1) $. By doubling the load on the tire to $ (W_2 \u003d 2W_1) $, which corresponds to 100% overload, the energy loss will also double to the level $ (R_2 \u003d 2R_1) $ at a constant pressure level $ (p_1) $.

Table 3: Relative values \u200b\u200bof tire pressure level and energy loss at different tire load

The tire congestion rate and the inflation rate of the tire must be below certain limits for safe use. Overloading the tire and / or changing the pressure level in the tire has a tremendous impact on energy loss, which in turn greatly affects the fuel consumption of the vehicle.

As mentioned earlier, energy loss is inversely proportional to the pressure level in the tire. This means that the increase in pressure can partially or completely offset the effect of the tire load limit. Let's assume that the load level on the tire is increased to the level $ (1.1W_1) $. How high should the tire pressure be to keep the energy loss at the original $ (R_1) $ level?

Table 4: Overload conditions and required pressure level to maintain a constant level of energy loss

Overload level Energy loss (N) Required pressure level (kPa) $ (W_1) $ $ (R_1) $ $ (p_1) $ $ (1.1W_1) $ $ (+ 10 \\ text (%)) $ $ (R_1) $ $ (1.21p_1) $ $ (1.2W_1) $ $ (+ 20 \\ text (%)) $ $ (R_1) $ $ (1.44p_1) $ $ (1.3W_1) $ $ (+ 30 \\ text (%)) $ $ (R_1) $ $ (1.69p_1) $ $ (1.4W_1) $ $ (+ 40 \\ text (%)) $ $ (R_1) $ $ (1.96p_1) $ $ (1.5W_1) $ $ (+ 50 \\ text (%)) $ $ (R_1) $ $ (2.25p_1) $

Increasing the tire pressure can be an inexpensive and convenient way to reduce rolling friction as the load on the tire increases. These combinations of load and pressure parameters are likely to maintain a constant level of fuel consumption, as the energy loss in the tire remains at $ (R_1) $. However, the driver of the vehicle should be aware that increasing the tire pressure makes driving harder and less comfortable.

Fuel economy indicator

In addition to energy loss, fuel consumption depends on the characteristics of the vehicle, driving style, frequency of stops and driving on congested roads.

Here, the reduction in fuel consumption only from energy loss in tires is considered. Over the past two decades, about 70% of the reduction in energy loss for pneumatic tires has been achieved by changing the tire design from corner to radial. The first question that arises in this regard is as follows: how much fuel can be saved with a certain percentage change in energy loss? Fuel saving index $ (F) $ can be defined as:

Some researchers have published experimental data on the change in fuel consumption as a function of rolling friction. D. Schuring (Schuring D) in his reports presented detailed experimental data for different types tires. The results of his research showed that the value of $ (F) $ is approximately $ (3-4 \\ text (%)) $ reducing energy loss saves about $ (1 \\ text (%)) $ fuel consumption for truck tires and $ (5- 7 \\ text (%)) $ reduced energy loss saves $ (1 \\ text (%)) $ fuel for passenger tires. These values \u200b\u200bare based on radial tire construction (see.

Change in rotational energy loss and fuel consumption

Next, consider the impact of increased energy loss on truck fuel consumption. Some results were presented in the table. For example, when the bus is 70% overloaded, the energy loss increases by 70%. Based on this, it can be assumed that with an overload of 100%, the energy loss will also double at a constant tire pressure $ (p_1) $. These results represent an increase of one tire.

Using D. Schuring's results, it can be concluded that a 100% increase in tire energy loss will increase fuel consumption by 25-30%. Typically, a truck or bus has 4, 6 or 12 tires. Thus, when the vehicle is twice overloaded, the fuel consumption increases by 2-2.8 times. This means that a driver of a vehicle can make two or more trips at an initial load level $ (W_1) $ at a standard tire pressure $ (p_1) $ using the same amount of fuel as in a double overload. In other words, the previous analysis leads us to the conclusion that fuel consumption for two trips with normal tire load will be slightly less than one trip with 100% overload. In this case, the same amount of cargo will be transported.

case 2 (double overload and one trip).

The disadvantage of the first case is the additional transportation time and additional costs for one more flight. From the point of view of using tires, in the first case, they will have to drive a double distance, but in the second case, the useful life will also be reduced due to congestion.

The standard calculations above have shown that if the tires are overloaded $ (2W_1) $ twice, the energy loss increases by 100%, which causes an increase in fuel consumption by 25-30%. Moreover, as shown above, increasing tire pressure by 50% to $ (1.5p_1) $ reduces energy loss by 63% or fuel consumption by 8-10%. The vehicle driver must consider these factors. Fuel consumption is usually the main expense on a flight. Knowing the values \u200b\u200bof energy loss at different tire load levels and tire pressure levels can help reduce and optimize fuel consumption. Perhaps with a slight increase in tire load above the standard value, the driver should slightly increase the tire pressure level so that the costs of driving a vehicle (fuel cost and tire cost) are minimized.

Vehicle operators should also take into account the possible load and tire pressure combinations shown in the table. This analysis allows you to reduce fuel consumption by monitoring tire load and pressure.

Conclusion

A truck or bus carrying a load with twice the tire load from the recommended level uses 30% more fuel than the manufacturer's recommended load level. The driver of the vehicle can change the load on the tire and the pressure in the tire. Changing the tire pressure is an easy way to optimize your vehicle's fuel consumption. Increasing the tire pressure is an inexpensive and convenient way to reduce fuel consumption for both passenger cars and trucks.

Terms and concepts

Hysteresis - this is a lag (at least if you translate this word from the Greek language), that is, a phenomenon in which the tire is in contact with the road, deforms with a delay, and then returns to its original form with a delay. In practice, tires with high hysteresis (soft / sticky) have a higher rolling resistance, while tires with low hysteresis will have significantly less resistance, which will save you more fuel. ...

Pressure unit conversion:

1 atm \u003d 101325 Pa \u003d 101.325 kPa
1 bar \u003d 0.1 MPa
1 bar \u003d 10197.16 kgf / m2
1 bar \u003d 10 N / cm2
1 Pa \u003d 1000MPa
1 MPa \u003d 7500 mm. rt. Art.
1 MPa \u003d 106 N / m2
1 mm Hg \u003d 13.6 mm wc
1 mm water column \u003d 0.0001 kgf / cm2
1 mm water column \u003d 1 kgf / m2

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Why don't you eat fly agarics? Customs exhaled sadness.

What is happening in the international road transport market? The Federal Customs Service of the Russian Federation has banned the issuance of TIR Carnets without additional guarantees for several federal districts. And she notified that from December 1 of this year she would completely break the agreement with the IRU as inappropriate to the requirements of the Customs Union and put forward non-childish financial claims.
The IRU responded: “The explanations of the Russian FCS regarding the allegedly owed debt of 20 billion rubles to ASMAP are sheer fiction, since all old TIR claims have been completely settled ..... What do we, ordinary carriers, think?

Stowage Factor Weight and volume of cargo when calculating the cost of transportation

The calculation of the cost of transportation depends on the weight and volume of the cargo. For sea transport, volume is most often decisive, for air - weight. For road transport of goods, a complex indicator plays a role. Which parameter for calculations will be selected in this or that case depends on specific weight of the cargo (Stowage factor) .

Tire inflation pressure is an indicator that directly affects the safety of the driver and passengers. Low pressure levels can lead to delamination and tire wear. Tires with increased internal pressure, they poorly compensate for road irregularities and significantly reduce driving comfort. Trucks are very sensitive to tire pressure readings. in them the weight of the cargo is constantly changing. Accordingly, the load on the tires is different each time.

Truck tire pressure can take on two main parameters:

Maximum pressure. The maximum allowable pressure is indicated by each car manufacturer on the sidewall of the tire. It is highly discouraged to exceed this value. excessive pressure can lead to a decrease in the elasticity of the tire and its subsequent puncture.
Recommended pressure - the tire pressure, which varies depending on the axle load and the tire size. This value is set by the manufacturer and shows the average load on a specific vehicle axle at the maximum permissible load. Recommended wheel pressure in truck can be found in a special table.

Truck tire pressure: Recommended pressure table based on axle load and tire size (front axle)




							7,500 at 8.5 bar

							6500 at 8.75 bar

Pressure in truck tires: table of recommended pressure according to axle load and tire size (rear axle)

	Air pressure in bar at various axle loads

							10,900 at 7.8 bar
							12,000 at 8.0 bar

							11,600 at 8.0 bar
							13400 at 8.0 bar
							12,000 at 9.0 bar
							13400 at 8.0 bar

Truck tire pressures must be checked at least four times a month. The pressure is measured on cold tires before driving. It should be borne in mind that after a trip, the pressure in truck tires can be 20-25% higher, this is due to the design features.

Buy truck tires and special tires in St. Petersburg by best prices is available in the online store "Spbkoleso".

The most important factor affecting safety and driving comfort is such a parameter as the correct pressure in the wheels of the car. Without properly created conditions, the safe use of the car cannot be ensured.

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What should be the pressure in the tires of the car (table), we will consider in more detail. Many car owners are concerned about the tire pressure of their cars. It depends on how quickly the process of tire wear occurs, the nature of the car's behavior on the road, fuel consumption, braking distances and much more. Tire pressure, especially in winter, affects safety. Based on the above, it follows that every vehicle owner should know what the pressure should be in the tires and make regular checks.

Car tire pressure

This value is not constant. Depends on the temperature outside, and in what conditions the iron horse is used. In winter, the pressure will be lower, as due to the rise in temperature, the air masses expand. When driving fast the surface of the wheel tires heats up, which also leads to an increase in tire pressure.

Factors influencing the choice of tire pressure:

car model;
weight and carrying capacity of the machine;
wheel diameter;
driving style;
road condition;
season;
winter or summer tires installed on the machine.

As a rule, manufacturers indicate what should be the pressure in the tires of the car specific brand and models.

Manufacturers indicate what should be the tire pressure of a particular car brand

What happens if tire pressure is not observed

It is very important not to violate the recommended pressure. This will help to avoid many serious problems and breakdowns. The manufacturer indicates recommendations not in order to violate them, but in order to properly and efficiently operate the car.

Many unpleasant situations on the roads arise precisely because drivers are rather negligent in checking this parameter. Incorrect tire pressures are especially acute in a car when overloaded. On slippery roads in winter time there are problems when braking. It is the trucks, with emergency brakingoften roll over because there was insufficient pressure in one of the wheels.

There is a possibility of damage to body parts, as well as failure of the suspension.

Problems arising from non-compliance:

vehicle drifts and overturns during sudden braking;
it is difficult to hold the steering wheel, the car skids;
fuel consumption increases;
breaks down steering system and a rail under constant pressure;
rubber is quickly and unevenly erased.

Both under-pumped and over-pumped wheels will sooner or later create problems.

In case of problems with tire pressure, the car may drift

Under-inflated tires

If the pressure is below normal, then the roll of the tire increases when cornering. The car can simply be carried off the road or the wheel can be disassembled. Serviceable steering does not affect the situation. How many terrible accidents happened due to driver oversight.

Why are under-inflated wheels dangerous?

rubber wears out quickly;
tires overheat and become unusable much faster;
during bends, the car is more diverted to the side.

Inflated tires

Pumped-over tires are also evil for cars. The wheels get stiffer and roll easier, the road grip gets worse. Vehicle handling is impaired. When falling into a pit, not only tires can be damaged, but also the suspension and even some body elements.

Consequences of over-pumped wheels:

quick wear of the car suspension;

Due to tire pumping, there can be quick wear of the car's suspension

the course of the car becomes stiffer, which increases the load on the suspension;
noise in the cabin from wheels.

Dependence of tire pressure on climatic and road conditions

The condition of the road surface affects the comfort of driving. If the roads are good, you can safely use the data of the tire pressure tables indicated in the manual for the car and enjoy driving without fear of car breakdowns and troubles on the way. If the roads leave much to be desired, then you can under-pump the wheels. This will soften the suspension and add comfort. In winter, when leaving the garage box in the cold, be sure to measure the pressure. It is necessary to monitor the indicators in the off-season.

What should be the optimal pressure

Each car has a manual. Study it, it contains information about the correct tire pressure (table), recommended specifically for your car. If the instructions for some reason did not appear, then this information should be indicated on inside driver's door... The above information shows lowest pressure air in car tires recommended by the manufacturer.

Pressure in hyundai tires Accent

Do not rely on the label for the correct pressure indicated on the rubber. The maximum allowable value is shown there, but you need to focus on the recommended one. It is best to measure performance in morning hourswhen the temperature of the wheel and air are approximately the same. In this case, the measurements will be more accurate.

Recommended tire pressure in winter and summer is influenced by vehicle weight and rim diameter. The measurement should be carried out on all 4 wheels, and also monitor the condition of the spare wheel. If instead of a standard spare wheel you have a "stowaway", then keep in mind that the indicators in it should be slightly below the norm. There is a special table of tire pressure by size, it also indicates the norms, taking into account the car brand and seasonality.

How to measure pressure: the correct sequence

The main stages of measurement:

Unscrew the nipple cap.
Using a pressure gauge, measure the pressure in the wheel. The device should be put on tightly and during measurement should not “etch” the air. Otherwise, the measurements can be considered inaccurate.
Screw on the cap.
It is imperative to check all four tires, this is the only way the readings can be considered accurate.

Checking tire pressure

In summer

There is no difference whether it is winter or summer time Years: The tire pressure must be the same all year round. Experienced car owners reduce the recommended figure by 5-10%. This is due to the large number of holes on the roads. Under-inflated tires make the ride softer, which adds comfort to the driver and his passengers.

In winter

The stability of the car on a slippery road increases.
The braking distance is shortened.
The suspension softens.

Increases car stability on slippery roads

Do not try to measure tire pressure visually. It cannot be done. Only an employee of the service center with very extensive work experience can estimate this approximately. An approximate result cannot save you from trouble, so for your own safety, visit a specialist regularly, or take measurements yourself.

You can slightly exceed the value. In this case, you will save on fuel consumption. However, do not exceed the values \u200b\u200bindicated on the tires, this will only lead to trouble. If you have to travel a long distance or need to transport a heavy load, it is worth increasing the tire pressure.

When inflating the wheels, always consider the heating difference. On a hot sunny day, the tires get hot and in a car that is just standing, consider this.