Is it necessary to do a wheel alignment after replacing the front struts?

The chassis of a vehicle is rightfully considered a complex unit where the elements are connected to each other. The suspension provides a comfortable ride and affects the safety of the car. If the car's suspension system is capricious, it negatively affects handling. The car handles worse on the road and loses maneuverability.

The problems mentioned above fully relate to the car's depreciation system. Today, our goal is to find out whether it is necessary to do a wheel alignment after replacing shock absorbers.

Installation angles

All installation geometric angles are measured in degrees, with the exception of the toe angle, which is most often measured in millimeters in European countries.

Vehicle suspension parameters are measured from several angles:

toe-in;
camber (Gamber);
caster;
longitudinal angle;
transverse angle;
kingpin angle.

The main setting angles are the first three, that is, toe, camber and caster angles. Changing any of these angles significantly affects the geometric parameters of the wheels. In order to understand what a wheel alignment is, it is worth examining each corner separately in detail.

Toe-in

Toe-in is translated from English as wheel toe-in and generally has a positive meaning; traditionally, Subaru models have zero toe-in, and negative settings are used exclusively on sports racing cars.

Positive toe is considered when the front part of the tire is directed inward towards the longitudinal central axis of the car, and negative when it deviates outward. The deviation of this angle affects:

for increased tire wear;
handling when turning;
vehicle rolling distance.

On rear-wheel drive vehicles, positive toe-in is considered to be within 1 to 2 millimeters, and on front-wheel drive vehicles, from 0 to 1.5 mm. The adjustment units are located on the steering rods.

Camber (Gamber)

The camber angle can be either positive or negative depending on the design features of the vehicle suspension. On rear-wheel drive vehicles, positive yaw deflections are usually used in the range from 0 to +1 degrees. Front-wheel drive vehicles generally have negative camber from 0 to -1 degrees. Significant deviations affect handling and contribute to wheel tread wear.

The main reasons for violation of the Gamber angle are:

When these malfunctions occur, the wheel begins to deviate towards negative camber, while the toe-in of the wheels changes, quite often the initial position of the steering wheel changes, the car is felt to pull away, and wear marks appear on the tread on one of the sides.

It is worth noting that not all cars, especially cars with MacPherson strut suspension, have adjustment units for this angle. On earlier models, eccentric bolts were installed on the lower arms or shock absorbers for adjustment. So, for example, on the VAZ 2108 model, the upper bolt securing the shock absorber strut to the axle is eccentric, which allows adjustment work. Gradually, the engineers abandoned this idea. Therefore, if the camber deviates from the factory parameters, the reason should be sought in the elements of the chassis or body geometry.

Caster

A very important and responsible angle, violation of the parameters of which leads to the car moving away from straight-line motion; in fact, the front axle of the car’s wheels shifts in relation to the rear axle. Caster stabilizes the vehicle's handling at high speeds and ensures that the steered wheels return to their original position when turning. The angle is always positive, and the higher it is, the more stable the car is at high speed. On ordinary cars the range is from two to five, and on sports cars the tilt reaches nine degrees or more.

Reasons for changing caster tilt may include:

the lever is deformed due to hitting an obstacle;
silent blocks destroyed;
spring is broken;
the shock absorber strut is deformed (MacPherson system);
deformation of the front subframe or body.

Almost all SUVs have units that allow you to adjust the angles of the wheels, which are located at the point where the levers are attached. Two adjustment methods are used:

eccentric bolts;
adjusting plates or washers.

On the VAZ 2121 the unit is located on the upper arm; washers are used, by installing or removing which adjustment work is carried out. Imported SUVs have special eccentric bolts located on the lower or upper suspension arms.

When do you need to adjust toe and camber?

Adjustment of the RS can be planned or unscheduled. In the planned version, its regularity depends on the recommendations of the vehicle manufacturer. Domestic cars need a procedure every 10-15 thousand kilometers. Foreign vehicles should be shown to service station technicians after 30 thousand kilometers. When answering the question of how often to do a wheel alignment, experts advise contacting the service at least once a year. The best time is spring, when replacing winter tires.

Unscheduled adjustment procedures may be needed in the following cases:

accelerated tire wear or tire replacement;
spontaneous deviation of the car to the side while driving on the highway;
side impact of the wheel on an obstacle, which causes a dent on the disk;
replacement of chassis parts (shock absorbers, suspension arms, silent blocks and other elements);
changing ground clearance parameters (shortening or lengthening springs);
after a long drive on roads without high-quality surfaces;
aggressive driving style.

Result of wheel alignment adjustment:

increasing vehicle stability;
improved handling;
minimal risk of skidding;
fuel economy;
reduced tire wear.

How does the wheel alignment work?

Let's look at the main features of adjusting the rear wheels, depending on the type of stand used. Optical stand. When adjusting wheel alignment using it, optical beams are projected onto two special screens on which diagnostic marks are applied. There is a hole in the center of each mark. The car is positioned between these screens, and small mirrors are attached to its wheels. During adjustment, optical rays are reflected from the mirrors on the wheels and hit the screens. Based on the distance between the hole in the control mark and the place where the beam hits the screen, the required wheel alignment angle is determined. If the optical stand is well calibrated, and the adjustment is made by a sufficiently qualified mechanic, then the result of the adjustment will be satisfactory. Computer stand. Increasingly, computerized stands are being used at service stations, allowing wheel alignment adjustments to be made faster and with much greater accuracy. When using them, electronic sensors are attached to the wheels, which transmit information to the head unit using a radio signal or a laser beam. The angle of rotation during camber and toe, the relative position of the wheels and the overall geometry of the suspension are recorded on the monitor and memorized by the computer, after which they can be printed and used by the master for adjustment. Computer 3D stand. The most modern diagnostic method. Special reflective targets are attached to the wheels. Digital cameras connected to a computer track their movements, and the received information is instantly processed by the processor. Camber and toe are determined very quickly: you just need to turn the steering wheel to the sides, and also roll the car forward and back a short distance.

How to understand that the wheel alignment is poorly adjusted

A serviceable car drives smoothly and evenly - it does not pull to the side or throw when braking. But when the settings go wrong, on a straight road the steering wheel pulls away and the car “floats”. In addition, tires wear out quickly. Even an amateur will understand when the camber is out of balance. If you notice one of these deviations, then it’s time to go to the service station:

The tires squeak even when turning slowly.
When you drive straight, the car gradually pulls to the side.
To drive straight, you have to keep the steering wheel turned slightly.
Tires wear out quickly.

Often the reason is not due to natural wear and tear, but to interference with the suspension components. After the repair, the wheel alignment becomes misaligned and the car drives poorly - you need to look for a service station again to fix it. Unpleasant. Find out after what repairs the camber is adjusted, and immediately do everything correctly.

What factors can affect the accuracy of measurements?

Of course, the accuracy of the procedure depends on the correctness of its implementation. Only if you strictly follow the protocol and correctly carry out all the settings can you achieve an impeccable result.

First, you need to conduct a visual inspection of all suspension elements, paying special attention to steering systems, ball struts, and silent blocks. If there are gaps, there is no point in carrying out further diagnostic procedures - the defect must first be eliminated

If there is no play, the tire pressure is checked (diagnostics on 3D stands allows you to skip this step, since the equipment independently recognizes the tire inflation level based on the outer diameter).

After this, the suspension is unloaded as much as possible, sensors are attached to the wheels of the car, and vibration compensation is performed (due to the use of uneven rims, appropriate adjustments are made to the program).

In some vehicle models, checking wheel alignment on a stand requires additional loading of the passenger compartment, equivalent to the total weight of the driver and one or two passengers. If the operator does not take this point into account, the result produced by the stand will be incorrect.

Of course, do not forget about the annual inspection of the stand itself. To ensure maximum accuracy of results, equipment must systematically undergo routine diagnostics. The platform intended to accommodate vehicles must be perfectly level and securely fastened.

Do I need to do an alignment after replacing shock absorbers?

The road is a dangerous place. And life depends on the health of the machine. The traffic is crazy, the speeds of new cars are high, not to mention those road users who consider everyone an enemy. The only hope is in the strength of your hands and the strength of your suspension.

Controllability is another factor affecting safety. If the wheel alignment is incorrect, the steering wheel steers, and the car pulls to the side when you brake. Intervention in the suspension leads to a violation of the settings, and therefore whether it is necessary to do toe-in after replacing the shock absorbers is a question on which the reliability of the vehicle directly depends.

I changed the struts, do I need to do a camber?

The problems mentioned above fully relate to the car's depreciation system. Today, our goal is to find out whether it is necessary to do a wheel alignment after replacing shock absorbers.

Why do you need to do a wheel alignment?

Wheel alignment must be done in any case, since incorrect installation or its complete absence leads to very rapid wear of the tires and deterioration of vehicle controllability. Camber is the angle of the wheels to the road. Depending on the needs of the motorist, it can be either positive or negative. In the first case, the upper part of the wheel is tilted towards the center of the car by about 1.5 - 2 degrees. This camber is not desirable as it increases tire wear, but it also provides better traction. In most cases, positive camber is set.

Toe-in is the difference in distance, which is measured along the front and rear points of the wheels (discs) horizontally. It is measured in millimeters or degrees. It can also be positive. Negative and zero. Positive toe-in of the front wheels provides stable control at high speeds, but at the same time maneuverability, that is, steering, deteriorates. If the toe is negative, then it is easier to drive the car, since the reaction of the wheels to the rotation of the steering wheel improves. However, in this case, you will have to change the tires often, since they wear out very quickly on damaged roads. For the rear wheels the situation is almost the same. The best option would be to set the wheel toe to zero. This will keep both handling and tire longevity in balance. Normal wheel geometry angles provide the vehicle with fuel efficiency, easier handling and maneuverability, stability and a reduced tendency to depreciation and rollover.

It is also important to know the first signs of an unadjusted wheel alignment:

The car drives to the right or left;
Increased and uneven tire wear;
The need to replace steering and chassis parts.

If you have the above problems, then it would be best to immediately contact a car service center, where they will perform the necessary adjustment of the geometry angles at a special stand. A modern stand is capable of performing the necessary measurements and adjustments. The service center will provide you with a report on the work performed, it will contain the following items:

Camber angles of the left and right wheels for both suspensions (front and rear);
Toe angles (also for all wheels and both suspensions);
Offset of vehicle axles;
Rear axle rotation;
Transverse and longitudinal angles of inclination of the axis of rotation.

Before starting work, the technician inspects the car for faults, measures the tire pressure (it should be the same) and then adjusts the angles.

Which wheel alignment stand to choose?

I would like to note that it does not matter which stand you ultimately choose, computer or optical (laser). The main thing is what kind of master “breaker” will do it

A good and experienced master will do equally well on any stand, if he is a true professional, i.e. treats his profession and his equipment with soul and love. The stand of such a master is always precisely calibrated and you can safely entrust your car to him. The main difference between an optical stand and a computer stand is the accuracy of measurement. The advantage of an optical stand is that it is simpler in design and, as a result, more reliable in operation. The downside is that the optical stand can simultaneously diagnose only one of the axes, front or rear. If we make the front axle, then we will miss an important parameter, the angle error of the rear axle. The rotation of the rear axle directly affects the driving angle, stability and controllability of the vehicle. Therefore, when making adjustments on the optics, you need to take into account the likelihood that the steering wheel will have a slight tilt when the car is moving in a straight line. The computer stand is more accurate in measurements and does not have the disadvantage of one axis and can diagnose two bridges simultaneously. Because the adjustment takes place along two axes simultaneously, their location relative to the axis of symmetry of the car is taken into account, and if the car was in an accident and the geometry of the body is broken, then an experienced specialist will immediately determine this

It is worth noting that all this applies only to modern computer stands with a closed measurement loop. Old stands have an open circuit, as well as outdated software

Therefore, immediately pay attention to what equipment is available at the service station. A modern computerized wheel alignment stand allows you to get the adjustment results in printed form. Such a report will contain certain parameters and definitions. Let's explain some basic parameters.

What does an incorrect alignment lead to?

The topic of wheel alignment is constantly discussed on automobile forums. Urgent “technical treatment” is necessary when car rims point in different directions. Exactly like an unloaded Tatra. Unlike a Czech truck, the handling of a passenger car is significantly reduced. The thing is that refusal to perform wheel alignment threatens with serious troubles, which we will talk about a little later.

Experts say that in the work of well-coordinated mechanisms it is necessary to find a compromise. Goal: to set optimal operating parameters for all nodes.

When it comes to adjusting the steering wheel angles, it is important to decide and find the average:

Vehicle stability.
Controllability of machine control.

This is a compromise, or, if you like, a technical balance. Most often, the disks located in front correspond to the four most important indicators:

Disintegration.
Toe-in.
Fractional angles of repose of the rotating rod of the wheel.
Perpendicular to angles.

When you don't need to do a wheel alignment

No matter what you repair, the service station will tell you to do a alignment. They will argue that if you don’t adjust it, the ride will be uncomfortable and almost dangerous. Don't listen. Often, replacing components does not affect the wheel tilt adjustment and there is no need to pay for additional work. Read and remember whether it is necessary to do an alignment after replacing silent blocks, shock absorbers and wheels. You won't be deceived anymore.

Tire replacement

The misconception that after replacing wheels you need to do an alignment is spread by the service station workers themselves. But seriously, changing tires in the standard way does not affect components that are associated with suspension settings.

After replacing the wheels, wheel alignment is not necessary.

If your car pulls to the side with new tires, check the tire wear level.

Replacing shock absorbers and silent blocks

To replace shock absorbers, steering rods and ball joints are not unscrewed. Therefore, to replace the struts, there is no need to do a camber. Although it can be adjusted, there will be no harm.

It's a little more complicated with silent blocks. See if their replacement affects components that affect toe-in - rods, tie rods, ball joints. If it affects you, adjust it, if not, don’t touch it. Change the silent blocks in the struts without adjusting the camber - when installing shock absorbers, the steering elements are not touched.

Replacing stabilizers

The situation is similar to the previous one - when the stabilizers are changed, the main suspension components are not affected. Therefore, after repairing the stabilizers, do not buy a wheel alignment - value your time and money.

In what cases is it not worth adjusting the wheel alignment?

This operation itself, if it is carried out in a good car service center and with high-quality equipment, is not so little, especially if the adjustment is to be made on an expensive foreign car. Therefore, no one wants to pay money in vain.

Seasonal tire change

Roughly speaking, the wheels are not part of the suspension: rather, they are attachments. Someone may object: they say, they changed the tires, and the car began to pull to the side. This happens due to uneven tread wear: for example, if you installed used tires and did not properly inspect them.

Replacing shock absorbers and stabilizers

If the suspension has been repaired, then as for the second parts, they do not affect the alignment in any way. The same can be said about shock absorbers if they need to be replaced. In most cases, they are installed at the front inside the spring and can be removed by unscrewing two or three (depending on the model) bolts.

A few words about safety

More than the suspension, the only thing that affects driving safety is the brakes. To avoid getting into trouble, monitor their condition - change the pads on time and constantly check the amount of brake fluid. After replacing the pads, you need to bleed the brakes - this is not the law, but it’s safer and you’ll have peace of mind.

Keep an eye on the important components of the car - suspension, steering, brakes. A timely visit to the specialist will save you from many problems and costs.

When you feel that the car is not behaving normally, contact the station immediately, even if it is just a suspicion. It’s better to play it safe – it will get worse later. Timely maintenance will save you from accidents and the costs of future repairs.