Read to everyone: why is it so important to check the geometry of the body of your car?

Body geometry measurement

Many motorists can operate their car for many years without even knowing about such a thing as the correct body geometry. However, this concept is a very important factor affecting many parameters of the car, from its appearance to the safety of its operation. To figure out how to check the geometry of the body, it is necessary to more or less accurately determine what this body geometry is, how and in what cases it is measured, and what properties of the car are affected by its violation. You should also consider methods for conducting measurements at home and at specialized body repair stations with high-tech equipment.


What is the geometry of the car body? How and where to measure it? The body geometry of any car is defined as a set of distances between control points that are set by the manufacturer. They provide for the exact position of all body parts relative to each other, which ensures the correct operation of components and mechanisms that are attached directly to the body itself. These distances include the diagonal dimensions of the doorways, the engine compartment and the luggage compartment.

The most important are the distances between the reference points, which play a supporting role for the details of the running system. These include the distances between the spars, glasses and other body elements on which the undercarriage is attached.

As a result, the wheelbase of the car, the track width and other parameters that affect not only the comfort of the ride, but also its safety depend on the correct geometry of the body. Therefore, the geometry of the body should be given special attention. But first you need to figure out where its violation comes from.

Causes of violation of body geometry

The reasons for the violation of the geometric position of certain elements of the body can be factors such as:

  • bumps on the roads;
  • various kinds of obstacles;
  • traffic accidents and more.

Depending on the severity of one or another factor affecting the geometry of the body, the dimensions between its control points also change in different ways.

For example, when operating a car on rough roads or when accidentally hitting obstacles, the car's suspension partially takes on the load. However, the body of the car, even unnoticed by its owner, also takes on these effects, as a result of which it gradually deforms.

Body Geometry Check

Grounds for an audit

Nowadays, a body geometry check is most often carried out before buying a used car. This procedure helps the buyer to determine if the car has been in an accident, how it has been repaired, and how it has generally been used.

Less often, measurements between the control points of the body are carried out in order to determine the quality of the body repair carried out by specialists. Often, after restoration work, the owner does not pay much attention to this issue. Looks nice, and that's good. And in vain: after accidents, not every body can be restored by simply returning the geometry by pulling parts. Some parts require replacement, some are cold drawn, others heated. And if you do not attach importance to this, then soon you can seriously pay for it.

The most responsible car owners measure the distances between body control points regularly. Some experts recommend doing this at least once a year. The most frisky service stations recommend that these measurements be carried out twice a year. Perhaps they are right, given the condition of the modern road surface.

Primary signs of geometry violation

For those car owners who consider regularly checking body geometry a waste of money, there are several signs that should definitely encourage them to do such a check. And the sooner this is done, the cheaper it will be to fix the defects.

The first signs of body deformation are poorly closing doors, hood and trunk. If this is not a consequence of sagging doors, then the deformation of the pillars and other body parts is obvious.

A more dangerous sign of deformation of body parts is the unstable behavior of the car when driving at high speed. The car can pull in different directions, throw and scour back and forth, vibrate and so on. If the running gear is in good condition, then the deformation of the spars, glasses and other things is obvious.

Self check

Even at home, with a tape measure and the Internet, you can measure many distances between body control points. In most cases, the manufacturer gives these same dimensions in the form of understandable drawings in the instruction manual that came with the car when it was sold.

If this data is not at hand, it is quite easy to find the corresponding figures for the most common car models on the Internet. Here it is very important to search for values ​​for a specific car model. Even on very similar cars, these parameters may differ.

Already manually, without the use of complex and expensive equipment, you can easily measure the distance between the glasses, the diagonals of the doorways, the track width, and so on. To carry out some measurements, it may be necessary to dismantle the trim, bumpers and other parts that block access to the measuring points indicated in the instructions.

Checking the geometry of the body at special service stations

If the measurement of body distances is carried out on special equipment, then the owner should take into account that such a procedure is quite expensive. However, it can pay off in some cases. For example, the camber and toe adjustment wizard gives you a verdict that these parameters are no longer configured on your car. And this despite the new parts of the chassis. Measurements of body geometry will help determine the cause, as well as eliminate these defects.

To measure the geometry of the car body at special stations, high-tech equipment is used, which is distinguished by the highest accuracy. With its help, the masters will be able not only to measure the distances between control points, but also, if necessary, offer you the correction of deformed parts.

Checking the geometry of the body at the service station

The most modern equipment for measuring geometric distances consists of a special stand on which the car is preliminarily fixed in a semi-disassembled form. Usually, in order to make all the necessary measurements, it will be necessary to dismantle the trim parts of the interior, bumpers and other decorative elements. It may also be necessary to dismantle the parts of the chassis system.

After fixing the car and other preparatory work, special electronic sensors are installed on the control points of the car, which fix and transmit their position in three-dimensional space to the main computing device. After running the diagnostics, the wizard can see all the necessary distances, as well as those that do not correspond to the manufacturer's set values.

On the same equipment, the body geometry is also corrected using special hydraulic equipment. Such repair is more accurate than manual measurement and straightening with improvised means.

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