In the realm of cars and everything connected with them, there are two concepts such as gross vehicle weight and curb weight. These are two characteristics that are always talked about in theoretical lessons at a driving school, but many even the most avid drivers manage to forget this terminology. In order to make it clear what all this means and how it affects the car itself, we will try to consider this issue in detail.

Brief interpretation of the term

So, the curb weight of a car is the total weight of the car. It includes all running parts, all interior filling (including audio-video equipment), as well as consumables such as engine oil, coolant and fuel (full tank). The indicator of this weight unit does not include the weight of the driver and passengers, as well as cargo and other parts that do not affect the operation of the vehicle's chassis. Based on the term itself, one can understand that this is the very "equipment", that is, equipment that ensures full readiness for the process of movement, braking, sliding, and so on.

Gross and curb weight of the car: differences

Unlike the curb weight, the full weight also includes the weight of the driver, passengers and transported goods. It is clear that all people are different, and each is characterized by its own mark on the scales. The same applies to luggage - you can store the car in such a way that it won't budge. That is why the term "permissible gross vehicle weight" is most often used among motorists. Each car has its own highest solvable mark, it all depends on the manufacturer, the materials used in the structure, as well as on the body structure and other supporting parts. It is important not to load your car so that this figure is exceeded. Otherwise, the body will gradually deform, as well as bridge systems and other parts that are attached to the suspension.

Exceptions to machine rules

As mentioned above, the curb weight of a car is the weight that is characteristic of it when fully “equipped”, with all consumables and accessories present. However, in some European countries, this weight unit also includes the driver's weight, but only if it does not exceed 75 kilograms. The Europeans came to this conclusion because it is the driver who causes the car to move, and without him the driving process will become impossible. In Russia, the curb weight of a car is, in addition to all the parts mentioned, also a spare wheel, tools that can be useful on the road in the event of an accident or breakdown, and sometimes a can of spare fuel.

Machine weight and its maximum speed threshold

It is also known from physics lessons that heavier objects will always move at a lower speed, since they have to overcome more resistance. What does the curb weight of a car and its technical characteristics mean, how do they interact with each other? In order not to delve into the study of the features of each model of each brand of modern cars, we will consider this issue on two types of cars: a two-seater coupe and an SUV. The weight of the first car is, of course, small. Yes, the engine, injectors and everything that provides a fast acceleration of a sports car takes a considerable share. However, its body is small, there are only two seats in the cabin, there is no luggage compartment. The weight of the jeep is two or even three times more, it has five or six seats, a multi-liter trunk. The fuel tank also takes up a lot of space, the volume of which is always extremely large. Logically, the Audi TT RS will move faster and more agile than

And motor vehicles as a starting weight. It should be understood as the true own non-operational mass of a motor vehicle or motor vehicle, taking into account the absence of fluids intended for its operation and spare parts (spare parts, tools, accessories).

Thus, dry mass can be considered the mass of an unprepared motor vehicle or motor vehicle without liquids (the fuel tank must be empty, other liquids (for example, coolant, brake fluid, fluid in the washer reservoir) and oils (for example, engine oil and gearbox oil) are also absent), showing only the weight of parts included in its design that are not related to spare parts (spare parts, tools, accessories). Many cars and motorcycles with a sidecar have a spare wheel as a spare part. A jack is standard on many vehicles. There is ambiguity about what exactly belongs to the accessories. By the logic of things and by analogy with tools, accessories can be considered parts that assume free fastening with the possibility of removal during operation (almost every car has rugs that can be removed from the passenger compartment, in the trunks of many cars the jack is covered with a plastic cover, in some Rolls-Royce models they are hidden in the doors umbrellas). Also, accessories include external hinged-type parts that are installed just for the daily operation of the machine, which perform the following functions: cargo transportation (towbar, skids for securing cargo on the roof of the car body, nets on the headlights), protection and safety of the car (kenguryatnik, fly-hoe, protection engine crankcase), auxiliary (winch), protection and safety of people sitting on the motorcycle (wind and knee shields, as well as the roll bar),

This name is explained by the fact that a motor vehicle or motor vehicle remains primarily without fluids necessary for its operation, and the containers in which these fluids were located are dried. To designate the non-operational mass of the machine, implying both the absence of fluids and spare parts, the term dry mass was created, taking as a basis only the absence of fluids. This term is mainly used by manufacturers to define the non-operational mass of a machine.

The following weights are:

• curb weight: the weight of the vehicle with fluids and spare parts, but without people and cargo. Although some documents contain instructions to include in the curb weight the weight of the average driver equal to 75 kg. In this case, it is reasonable to indicate that the curb weight is including the driver.

• gross weight (permissible maximum mass): the weight established by the manufacturer as the maximum permissible in operation mass of the equipped vehicle with cargo and people. Subtracting the curb weight from the permissible maximum mass, we get the carrying capacity. However, in practice, many owners of especially trucks load them more than the maximum permitted weight. This can be seen from category "B" trucks to giant dump trucks. This leads to increased wear of parts and the supporting system of the car, since the very criterion for setting the permissible maximum weight implies a long-term operation of the machine.
• maximum permissible weight: the maximum weight of the equipped vehicle with people and cargo that the structure of the vehicle cannot support.

Trucks can damage the road surface and are a source of increased danger to other vehicles. Especially for such vehicles on the territory of Russia, there are special rules governing the permissible maximum weight of a truck and the permissible overload. If they are violated, penalties will be imposed on the culprit.

Legislation and general provisions

Heavy vehicles are a serious load on the road surface. To minimize its damage and ensure road safety, restrictions on the maximum weight of a truck were developed and liability for their violations was introduced.

In the Russian Federation, these norms are given in Federal Law No. 257 and Government Decree No. 272. The State Traffic Inspectorate is obliged to monitor the implementation of the norms.

Truck drivers should pay attention to the following points:

• The norms apply exclusively to public highways of territorial or federal significance.
• Overloaded vehicles must only be driven on special roads.
• If the roadbed is not able to withstand the load established by law, its owner has the right to establish his own restrictions.
• Before lowering the restrictions on the maximum permissible machine weight, a survey of the condition of the roadway must be carried out.
• Highways with restrictions for heavy vehicles must have road signs warning drivers of this.
• Axle load limits depend on the vehicle's operating instructions.

Maximum dimensions of freight vehicles

The maximum permitted parameters of heavy-duty transport are set in the agreement of the CIS countries. According to him:

• The length of a car, trailer and bus should not exceed 12 m, for an articulated bus this parameter is 18 m, and for a road train - 20 m. Lifting platforms, steps, windshield wipers, mirrors are not taken into account in the calculation of the length.
• The width of any machine is less than 2.55 m. This does not include lights, stairs and steps, platforms, mirrors, tire pressure indicators.
• The permitted height is 4 m including body or container.

Maximum permissible weight for freight transport

The maximum weight of a truck is otherwise called gross weight and is the sum of the weight of the truck itself and the load.

All heavy vehicles are divided into three categories:

• low-tonnage;
• medium tonnage;
• large-capacity.

To the class of low-tonnage include small trucks, including "Gazelle", in which the cab and body are on the same supporting frame. They are used, as a rule, in trade for the transportation of small goods over relatively short distances. The mass of such trucks is not more than 3.5 tons, and the carrying capacity, depending on the model, is from 0.5 to 2.5 tons.

They weigh more than 12 tons and are used to transport very heavy and bulky goods. They are often part of semitrailer and trailed road trains.

In addition to the maximum permissible weight of the transported cargo, one more parameter is important to check for overload - the axial load. Since the design of the machines implies a cargo compartment at the rear, the main weight of the cargo falls on the rear axle.

The permissible mass of heavy vehicles is given in Appendix 1, and the permissible axle loads are given in Appendix 2 to Government Decree No. 272. For example, according to this annex, a five-axle semitrailer train with five axles can weigh no more than 40 tons, and a three-axle vehicle no more than 24 tons.

For the passage of a vehicle with a gross weight of more than 44 tons, you need to issue a special permit, which indicates the route, departure and arrival times. For a car weighing 80 tons together with cargo, the route is drawn up by traffic police.

To avoid a penalty for axle overload, a special permit can be used

In order not to pay an overload penalty, you need to calculate the gross vehicle weight and axle load. These two quantities are related to each other by the following ratio: the total mass is equal to the sum of the loads on each of the axles. At the same time, in a two-axle vehicle, the load on the front axle is three times less than on the rear. For trailers, it is distributed evenly on each axle. The obtained values \u200b\u200bshould be compared with the table from Appendix 2 to the Government Decree No. 272.

According to Federal Law, overload can be no more than 2% of the permissible value.

In the event of overload, the culprit is subject to administrative liability in accordance with Article 12.21.1 of the Administrative Code. Individual entrepreneurs bear the same responsibility as legal entities.

Fines for exceeding the permissible weight of a truck are imposed on the driver, the official responsible for transportation, the legal entity and the owner of the vehicle. In case of overload of more than 50%, the driver is deprived of his license for up to 6 months.

In addition to overloading, fines are imposed in the case of:

• deviations from the route sheet;
• indication of false data on the weight of the cargo;
• lack of permission to transport bulky goods;
• exceeding the norm of vehicle dimensions by 10 cm.

In the automotive industry, there are terms such as gross weight and curb weight. These terms are the ones that driving schools must talk about in theory. But, today, even many drivers with great experience do not remember or do not know about it. The curb weight of the car is the total weight of the car with the necessary equipment, all materials that are needed during the operation of the car, a full tank of fuel, the weight of the driver, but excluding the passenger weight and the weight of the cargo.

The total mass is the mass of the car, which is extremely possible and consists of: the weight of the driver and passengers, the mass of the equipped car, as well as the weight of the goods.

What is the difference between curb and gross vehicle weight

If you look at the differences between these concepts, then the whole point boils down to what exactly can be included and summed up in the general criterion of mass. Compared with the value of the curb weight of the car, in the indicator of its gross weight still appears the weight of the driver, and the weight of all passengers, as well as the weight of the carried baggage.

Gross vehicle weight \u003d vehicle weight + weight of all people in the vehicle + cargo in the luggage compartment.

Curb weight \u003d vehicle weight without additional loads.

Of course, each person's weight is different. The same can be attributed to luggage. Therefore, drivers use terms such as “gross vehicle weight”. Each car has its own highest permissible indicator, everything will depend on the manufacturer, the materials from which the car is made, as well as the shape of the car body, etc.

Do not overload the machine. If this is not observed, then during the use of the car, deformation of the body, bridge systems, and also other parts that need to be fixed to the suspension of the car will occur. And do not forget that under the condition of the full curb weight of the car, the fuel will be consumed in large volumes. Also, weight is always taken into account when using a two-post lift.

All of the above tips for motorists are quite important information, especially if the driver does not have sufficient driving experience behind him. They should not be neglected or ignored. Because sometimes even experienced drivers and chauffeurs perform certain actions that may not seem at first glance ridiculous and trifling, but which can lead to consequences. Therefore, be careful and careful when driving.

Many requirements for the design of the car can be realized only if certain inertial (weight) indicators are maintained. These include the vehicle's mass and moments of inertia, as well as the position of the center of mass.

Curb weight

Depending on the state of the car, its mass can vary within a fairly wide range (for a truck, when loading, the mass increases by more than 100%).

Three interrelated mass indicators:

unloaded vehicle weight, that is, the mass of the vehicle without equipment (tools, spare wheel) and refueling. This indicator makes it possible to judge the consumption of materials, but it cannot give an idea of \u200b\u200bthe behavior of the car in real operating conditions.

curb weight, that is, the mass of a car with refueling and equipment, but without a driver and passengers. With this mass, the maximum possible acceleration dynamics is assessed.

gross vehicle weight - the total mass of the equipped vehicle, payload, driver and passengers. Assessment of the basic performance of the vehicle. The values \u200b\u200bindicated are estimates.

Due to the suspension, some structural elements of the car have the ability to move relative. The part of the structure of a motor vehicle that is separated from the wheels or axles by elastic suspension elements is called sprung... Parts of the chassis structure of a motor vehicle, the mass of which is not taken up by elastic suspension elements, are called unsprung... The lower the ratio of the mass of the unsprung parts to the mass of the sprung part of the structure, the better the smoothness of the vehicle. Consequently, with the same curb weight, a car will be more comfortable if the unsprung parts of the structure have a lower weight.

The payload of a truck is called carrying capacity and is indicated in his passport data in just one digit. Cars and buses are designed to carry passengers and their luggage, therefore, they are not characterized by carrying capacity, but passenger capacity. At the same time, for cars, the number of seats is indicated, including the driver, and for buses - the number of seats, the total number of seats and the total number of seats for transporting people during peak hours. Since the mass of passengers and their luggage is unknown, they are set by some conditional values \u200b\u200bthat can be used to calculate the total load. In our country, the mass of a passenger is taken equal to 75 kg, the mass of luggage is 10 kg per passenger in a car, 5 kg per passenger in a city bus and 15 kg per passenger in an intercity bus.

Center of mass position

From the standpoint of the implementation of a number of operational qualities incorporated in the design of the car, not only the indicators of own weight and payload of the car are important, but the distribution of normal reactions over the wheels of the car. This distribution is determined by the position of the center of mass.

The center of mass of the car is usually located in the longitudinal plane of symmetry, although its slight deviation from this position is possible when the load of the car changes. Obviously, the closer the center of mass is to any of the vehicle axles, the greater the load on it. Mass distribution affects on the stability and controllability of the vehicle, its cross-country ability, braking qualities and smooth running. In this regard, the reference literature indicates the values \u200b\u200bof the masses per vehicle axle. These indicators can be presented in absolute terms or in the form of a ratio (usually percentage) mass. From the point of view of ensuring cross-country ability, the mass of the car on the drive wheels is of particular importance. This indicator is called adhesion mass.

In most countries, in order to ensure the safety of roads, maximum permissible axle loads are regulated. Therefore, the characteristics of the mass distribution are also the basis for deciding whether the vehicle can be used in specific operating conditions. The use of more than two axles in the structures of heavy vehicles (trucks, and sometimes buses) is usually determined by the need to reduce axle loads to permissible values. Vehicles that exceed the permissible axle load are classified as off-road vehicles. Center of gravity position in height car influences on its handling, braking properties, rollover stability, while the absolute advantages from these points of view are cars with a lower center of mass.

Moments of inertia

With the same position of the center of mass and equal masses, cars can have different values \u200b\u200bof the moments of inertia. In general, the inertial properties of a structure, along with the above-mentioned mass indicators, can be characterized by three values \u200b\u200bof the moments of inertia (relative to three mutually perpendicular axes passing through the center of mass). Moment of inertia about the vertical axis has a great influence on the car's handling and its stability against skidding. Moment of inertia relative to the horizontal transverse axis affects the smooth running of the vehicle. Moment of inertia relative to the horizontal longitudinal axis may affect the stability of the vehicle against lateral rollover.

During the design process, the designer has the ability to influence the values \u200b\u200bof the moments of inertia of the vehicle mainly due to changes in its layout.