Curb weight, gross weight and other weight characteristics of a truck
Weight specifications – a group of parameters by which you can draw conclusions about own / curb weight / unladen weight, maximum permissible weight, payload, axle load and other important indicators.
- Types of truck weight characteristics and how they are determined
- Curb weight
- Payload, concept of payload weight
- Gross weight
- Maximum permissible load (kerb weight)
- Why do they determine axle weight distribution?
- Video “Permissible Maximum Mass, Penalty”
Knowing these points allows you to properly operate the vehicle, extend its life and avoid violating traffic regulations and, accordingly, receiving fines. Below we will consider in detail what parameters there are, how and for what they are determined.
Types of truck weight characteristics and how they are determined
Weight characteristics – a set of parameters that characterize the mass, capacity and other parameters of the truck. The main ones are:
- curb weight;
- gross weight;
- permissible / maximum weight;
- permissible axle load and others.
Knowledge of these characteristics is essential for proper vehicle maintenance, public and off-road operation, cost of operating hours, etc.
Depending on the situation, the approaches to calculations may differ. For example, curb weight is determined by weighing on special scales in a test laboratory and then comparing it with the manufacturer’s data. If the deviation exceeds 5%, the newly measured parameters are used.
The maximum kerb weight is calculated by adding the axle loads, namely the weight that is transferred through the vehicle axle to the track surface. At the same time, the value of the axle load may differ depending on the type of pavement.
The total weight is determined by taking into account the vehicle type and intended use. The maximum payload is taken into account, taking into account passengers, stated payload, filled tank and other parameters. As a rule, the basic weight characteristics are given by the manufacturer in the official documentation.
It is them that you should be guided in calculations. If you have doubts about the accuracy of the data or if you want to get more accurate information, you must check in a special laboratory (mentioned above).
The term “kerb weight” refers to the weight of the truck including its standard equipment and materials. In other words, during the weighing process, those things that come with the kit are taken into account. In many countries, the weight of the driver is added to this parameter. This is due to the fact that the car can not drive without a person anyway. This feature is stipulated in the directive 95/48 EU for Europe and GOST 33987-2016 for Russia.
The second name of the curb weight is the weight of the car without load. Its definition and method of calculation may vary depending on the position of the competent authorities in each country.
The following data are most often taken into account in the calculation:
- vehicle weight;
- standard equipment: keys / tools, first aid kit, spare, fire extinguisher and hoist;
- a full tank of fuel;
- technical liquids and grease;
- weight of the driver (taken as 75 kg).
The resulting figure is specified in the technical specifications of the vehicle.
Payload, concept of payload weight
The term “payload” shows how much weight a particular vehicle can carry. In simple terms, it is the difference between the gross vehicle weight and its curb weight. Violation of the manufacturer’s requirements in this matter entails damage to the body, disruption of the integrity of the axle and other elements that are attached to the suspension. There are two types of payload (or payload capacity):
- Nominal. Defined by the manufacturer and specified in the passport of the technical means. It does not change during operation and is taken as a basis for calculations.
- Real. This parameter may vary depending on the quality of the road surface. When driving on a good road, the truck, as a rule, will be able to carry more weight than it is prescribed in the documentation.
Carrying capacity is of key importance, because exceeding the established norm is fraught with destruction of some elements with the need to replace them and even an accident. In addition, exceeding the allowable weight can lead to a fine by the traffic police.
Carrying capacity parameter is also taken into account when laying the route, because some roads are not designed for heavy trucks. We must not forget that errors in determining the payload often lead to incorrect determination of the category of the car. As a result, you have to pay the wrong tax.
No less important weight parameter of the truck is the gross weight, which is the weight of the vehicle when taking into account the full load. In the process of calculation, it is taken into account:
- The curb weight of the vehicle.
- A full tank of fuel.
- Filled cooling system / lubrication of various components.
- Spare wheel.
- Driver and passengers.
- Load (taking into account the permitted payload).
In fact, this is the maximum weight of the truck allowed by the manufacturer, the excess of which is an infringement and can lead to malfunction: deformation of the body and a number of assemblies.
Maximum permissible load (kerb weight)
The permissible gross vehicle weight or the permissible load for the country’s roads must be taken into account when using the truck. If this value is exceeded, the truck is considered to be overloaded, which is dangerous. First of all it concerns the road surface, which is more quickly destroyed under the influence of great weight. In addition, an overloaded vehicle has other characteristics: it is slower to accelerate and harder to steer. The destruction of any assemblies due to excessive loads cannot be ruled out.
Permissible weight for a truck is calculated taking into account the curb weight of the vehicle and the maximum permissible weight for Russian roads (up to 44 tons). Each vehicle has its own requirements for the number of axles. Thus, this parameter is 18 tons for 2-axle trucks, 25 tons for 3-axle trucks, 32 tons for 4-axle trucks, and 35 tons for 5-axle trucks. A separate group includes automobile trains, for which this parameter is from 28 to 44 tons. Two types of inspection are used to control these parameters:
- Dynamic. Conducted at speeds up to 5 km/hour. The car is driven on special scales, which show the load.
- Stationary. Control is carried out in a large van, in which the vehicle enters to conduct measurements.
If the received parameter exceeds the weight of the truck allowed to drive on Russian roads, the driver gets a fine.
The amount of payment depends on exceeding the permissible level. For example, if the allowable parameter is increased by 2-10 percent the amount of the fine will be insignificant and will be limited to 10-15 thousand rubles. If the norm is increased by 50% or more, then the penalty reaches 45-50 thousand rubles.
Why do they determine axle weight distribution?
When asking about the maximum permissible weight of a truck, you should be guided by the weight distribution parameter. This parameter indicates how the curb weight of the vehicle is distributed across the axles in percentage terms. It greatly affects the vehicle’s handling and the likelihood of being fined if it deviates from the applicable limits.
The weight distribution can be changed by adjusting tilt angles, replacing springs/stabilizers or weighting a certain part of the machine. Optimal is considered when the load is distributed evenly to the two axles of the truck. For example, if the machine weighs 3 tons, then each axle will have 1.5 tons.
But this equality is difficult to achieve on trucks, because this factor is affected by the volume and location of the tank, the equipment of the machine, the location of the load and its nature, changes made and other parameters. In any case, the correct weight distribution ensures good handling, higher speed, less tire wear and greater safety in operation.
Generally speaking, the weight distribution affects the following parameters:
- Acceleration. If the load is shifted to the driving axle, it allows to avoid wheels spinning on a soft ground.
- Stability. While driving, the truck meets a powerful air flow that presses or lifts the machine. In the latter case, the front axle may need to be weighted down to achieve better stability.
- Tire wear when braking. When you apply the brakes, the load goes to the front axle, so you may need to unload it.
Special vehicle scales are used to determine weight balance. They are used to measure the weight on each axle of the truck. This equipment is found near bridges or at stationary traffic police stations.
In the measurement process, attention is paid to the maximum and permissible axle loads. The first parameter implies the permitted weight for passing some areas (it is often indicated on the signs), and the second one shows the passport data. If the driver does not know the principles of weight distribution and exceeded the maximum carrying capacity, there may be unpleasant surprises in the measurement process.
The importance of truck weight specifications is hard to overestimate, because the safety of operation and the service life of the vehicle depends on understanding these parameters and being willing to follow the stated requirements. In addition, if you follow the requirements in terms of permitted weight, you can avoid many problems with representatives of the traffic police.
Concepts of gross vehicle weight, kerb weight and maximum permissible weight
One of the key characteristics of a car is its weight. The weight of the vehicle directly affects fuel consumption and the operation of many systems provided in the car.
When choosing a new car, many buyers think about the question of its curb weight, gross weight and maximum permissible mass. After all, vehicles are often used to transport passengers and large loads. If the car is not designed for the necessary loads, it will be unsuitable for the planned mode of operation.
The driver must understand how many passengers and luggage he can take on board, so as not to damage his car, not to provoke a failure of the suspension or other components due to overloading.
The basic concepts of characteristics of mass of the vehicle are told at theoretical lessons at a driving school. Many people do not consider such information useful, but face with it after some time. Because of this, motorists have difficulties when studying this issue.
The concept of kerb weight
This is the most common concept, which is emphasized by car manufacturers, official dealers and which the drivers themselves look at.
The kerb weight of any vehicle is the weight or weight of the vehicle, which includes the weight of all standard equipment, operating materials, but does not take into account the weight of the cargo, passengers and driver.
Standard equipment usually includes a spare tire and tools. For consumables, it includes fuel, engine and transmission oil, coolants and other items.
You can describe what kerb weight is in any factory vehicle somewhat differently. It is the total weight of the components of a vehicle empty in terms of cargo, driver and passengers, but with the fuel tank filled, with all the standard tools, equipment and working fluids. In fact, it is a car in the form that is delivered to car dealerships. All the most necessary things are collected in it, but there is nothing unnecessary, which will be gradually accumulated by the car owner himself.
It is not difficult to define the value of this characteristic. It is conditioned by the fact, that the curb weight, as well as the gross weight of the automobile, is often spelled out in the documentation. But they mean different parameters. Therefore, you should first look at the technical passport. Also this information is available even before you buy the car, as the manufacturers and sellers necessarily write these parameters in the list of technical specifications.
It is important to add that the EU has adopted a slightly different standard, according to which the weight of the driver is included in the total kerb weight. In this case, the standard weight of 75 kilograms is taken into account.
The decision is quite reasonable and has a logical explanation. The thing is that the movement of the vehicle will be impossible in the absence of a person in it, that is, the driver. He is considered a significant component of the car, which is why automakers consider it wrong to count drivers as a useful load.
Curb weight has another name. It is the unladen weight. As for the total mass of the vehicle, then everything is somewhat different.
It is the concept of the gross weight additionally includes the weight of equipment, consumables, the driver, cargo and passengers. From this it is not difficult to determine the difference between these two concepts. It lies in the weight characteristics of the passengers in the car, the driver himself and the cargo located in the cabin or luggage compartment.
Another important characteristic is the dry weight of the vehicle. It refers to the net weight of the machine itself, its construction. In this case, the weight of standard equipment, fuel, consumables should be subtracted from the curb weight. Then we get the very dry mass.
Each country is entitled to use its own formula to determine the kerb weight of a particular vehicle. This is not surprising, since this criterion is the key for the passage of vehicles in areas where there are weight restrictions. This applies primarily to bridges, but also to dams and other similar structures.
As already noted, in Europe, the average weight of a motorist is added, i.e. the average weight of a person. Thus, it is possible to better form the data on the weight of the car.
If we talk about the rules for the Russian Federation, the following points are taken into account when calculating the kerb weight:
- 75 kilograms. As in the case of the European Union, in Russia, there is a rule of adding the average indicator of human weight to kerb weight. It is based on the simple notion that the driver acts as an obligatory component for the movement of the vehicle;
- if they are trucks or buses intended for long-distance travel, with a crew member’s space provided by design, 75 kilograms are also added;
- tools. The kerb weight necessarily includes a list of tools needed by the motorist;
- 90%. It is the volume of the fuel tank filled up, which is included in the kerb weight. If you take the standard tank volume of 60 liters and roughly calculate the mass of fuel, it turns out that the calculation takes about 55 kilograms as surcharge to kerb weight;
- spare. The obligatory component is a spare tire;
- jack, fire extinguisher, etc.
Summing up all these parameters with the dry weight, we get the final value, which is specified in the technical documentation of the car.
It is worth noting the fact that there are special formulas that allow you to individually calculate the kerb weight. This is especially true for trucks, which pass through special points for the weighing procedure. If you subtract the kerb weight from the scales, you will know the exact weight of the load, the maximum mass and other characteristics.
That is why in certain situations the inspection services use calculation formulas to determine this parameter.
Why it is important to know
There are a number of situations in life when a motorist needs or just needs to know the exact parameters of the curb weight of his or her vehicle.
Each vehicle has a certain weight limit for the weight of the load it is carrying and towing. If you get stuck and ask the driver of the car, which technically is not able to cope with such loads, to tow you, the consequences will be negative for both parties.
You also need to keep the kerb weight in mind when driving through difficult areas, bridges, dangerous places, etc. On the roads there are special warning signs that show what the maximum weight can be driven here.
Concept of payload weight
Having understood the concepts of vehicle weight without load, we are now interested in a slightly different vehicle weight. Specialists and ordinary motorists believe that the most important from the position of operation of the vehicle is such a characteristic as the payload. It is also called the payload mass. But the concept of carrying capacity is more clear and simple. From this the essence does not change.
Under the payload of the car means the total weight of all the cargo transported by the vehicle, which corresponds to the operational and general technical characteristics of the machines.
It is important to consider the division of the mass of the payload on the nominal and estimated.
In the case of the rated weight, only the weight that a particular vehicle is capable of carrying at most is taken into account. In the case of the rated necessarily takes into account the quality of the pavement on which the transportation is carried out. If it is a hard surface, then the cars are able to carry from 500 kg. of cargo and more. In the case of trucks and dump trucks, there are figures around 25-30 tons.
Car owners should carefully study the design and existing markings on their own vehicle. The thing is that some machines have certification plates on the door frame from the factory. Technical parameters are indicated on it, among which there are indicators of the weight limit load on each individual axle. As you understand, here we are talking mostly about trucks and commercial vehicles.
The concept of the total mass
Next, let’s figure out what the rules call the maximum permissible weight or gross vehicle weight. Many people identify such concepts as curb weight and gross weight of a car or truck. But that’s not quite right.
There is a significant difference between these values, which should not be overlooked. It would be a serious mistake.
If we talk about what means the total or maximum permissible mass of the car, it means the weight of the curb weight and the maximum loaded vehicle, which is laid down at the design stage of the model. Additionally, the weight of the driver and his passengers is taken into account.
Each individual brand and model of the vehicle has its own indicators of permissible or total weight. In many respects, this characteristic depends on the materials used in the manufacture of body parts, interior components and other components.
To calculate the limit or maximum permissible load (mass), you can use a fairly simple formula:
Mm (maximum mass) = Msn. (kerb weight) + Mg.p. (cargo and passengers) + Mv. (driver)
It is highly recommended not to violate the maximum load requirement of the vehicle. If there is too much cargo and people on board that exceeds the prescribed loads in the technical documentation, it will lead to serious problems. First of all the suspension will be damaged. Also the risk of deformations of the body itself increases.
Differences between full and curb weight
In order to finally understand these concepts, it is necessary to make a certain clarity concerning the kerb weight and GVW. Many people know that these concepts are different, but they can’t say exactly how they differ.
It’s all about what exactly is included in the total figures of the two characteristics. If you compare with the parameters of the curb weight, the weight of the motorist himself, i.e. the driver, the passengers on board and the cargo carried will be taken into account.
There is no denying the fact that not all people meet the standards laid down in the technical parameters. The weight of 75 kilograms is considered to be an average weight, as the driver may weigh 50 kilograms or 150 kilograms. People are different, and hence the difference in their weight.
Similar is the case with carried luggage and cargo. Someone practically does not use the luggage compartment, and at most carries a couple of bags from the supermarket a couple of times a week. Others regularly fill the trunk as much as possible with different items, things and goods. It comes to the fact that the rear suspension lowers from such a load, and the car can hardly move.
This disparity in performance has led to the active application of the concept of permissible gross weight. Each individual vehicle has a load limit, over which the design does not allow. Car manufacturers have already considered this at the design and production stage.
The more the vehicle is loaded, the more fuel is consumed, not only gasoline, but also oil consumption increases, tires are worn out faster, wear of suspension elements and the engine itself is accelerated.
It does not mean that the car cannot be used as a means of transporting luggage or passengers. It is not necessary to forbid anyone except the driver to sit in the car. But it is necessary to adhere to the load limits established by the manufacturer. Otherwise, you risk facing serious damage, body deformation and other troubles.
In reality, all the concepts discussed are quite simple. Figuring them out and determining the difference won’t be too difficult.