Radial and lateral runout is due to inaccurate rotation of the disc and tire.
100% rotational accuracy is not possible due to technical considerations.
Therefore, the manufacturer allows a well-defined tolerance for these parts.
If the rim and tire are mounted in a disadvantageous position, this may cause the maximum allowable tolerance for the rim and tire to be exceeded.
Table 4.3 lists the maximum tolerances for a tire mounted disk.
Checking the radial and lateral runout of a wheel with a tire using a dial gauge for tires V.A.G 1435
Lateral runout check
Rice. 4.15. Lateral runout check
Attach the indicator to the sidewall of the tire (Fig. 4.15).
Spin the wheel slowly.
Note: If the difference is greater than 1.3 mm, then the lateral runout is considered to be exceeded.
Note: In this case, you can reduce it by minimizing.
Checking radial runout
Rice. 4.16. Checking radial runout
Pre-tighten the dial indicator for tires by about 2 mm (Fig. 4.16).
Attach the indicator to the tire tread.
Spin the wheel slowly.
Record the minimum and maximum pointer deflection.
Note: If the difference is greater than 1 mm, then the radial runout is considered to be exceeded.
Note: In this case, you can reduce it by minimizing
Checking the radial and lateral runout of the wheel
Rice. 4.17. Scheme for checking radial and lateral runout
Place the wheel on a balance stand.
Use the self-expanding collet adapter for VAS 5271 balancers.
Pretension the tire dial gauge about 2 mm.
Spin the wheel slowly.
Record the minimum and maximum pointer deflection.
S - Lateral runout.
H - Radial runout.
Compare the obtained value with the nominal parameters in table 4.4.
Note: Deviations of the indicator needle due to small irregularities on the rubber should not be taken into account.
Note: If the measured value exceeds the rated value, normal running will not be achieved.
The problem of wheel balancing arose with the advent of the first cars. At low speeds and bad roads, it almost remained invisible. The situation has changed dramatically over time. Therefore, its relevance has increased dramatically.
Often, drivers observe signs of wheel imbalance. As a result, there is a beating of the steering wheel. Wheel disc runout caused by the displacement of its landing shelves during rotation. The displacement is twofold: parallel to the radius or axis of rotation of the disk. In the first case, there is radial, in the second - axial runout.
Wheel runout can be checked using a special indicator. It is pressed against the surface of the spinning wheel. The device registers the displacement of the wheel in the radial or axial direction. Readings are taken in millimeters. The amount of wheel runout cannot be visually assessed. The measurement accuracy of the indicator is not less than 0.05 mm.
Wheel runout associated with static imbalance. The disc takes an egg-like shape. The wheel oscillates up and down. The rotation of such a wheel is accompanied by the presence of a variable torque on the axle. The result is irreversible damage to suspensions, tires, steering gear.
Axial runout of the wheel is the result of the displacement of the disk along the horizon. Experts call this shift "eight". The axial displacement of the disk is caused by the uneven distribution of masses in the planes. Negative consequences of this defect:
- rapid tread wear;
- damage to the suspension and steering mechanism;
- uneven wear of the tire tread, which leads to a reduction in its service life.
Wheel imbalance is caused by the presence of asymmetrical rotating masses. In particular, it can be hubs, brake drums. Since the wheel is a body of revolution, it must be given a symmetrical shape. The balancing procedure consists in reducing the unbalance of the wheel to an acceptable limit.
The balance is disturbed due to rubber wear and various disk deformations. There may be other reasons that distort the shape of the wheel. A properly balanced wheel is essential for safe driving. The central axis of inertia of such a wheel coincides with its axis of rotation. The manufacturing process of wheels and tires is associated with certain errors. Therefore, the wheel is not balanced initially.
It is customary to distinguish between static and dynamic imbalance. Static imbalance has its own characteristics. The unbalanced mass serves as a source of torque. In other words, the wheel will oscillate. It will continue until the unbalanced mass reaches its lowest point. The wheel behaves like a pendulum.
The elimination of static imbalance is carried out by strengthening the balancing weight. The place of attachment of this load is the point opposite to the unbalanced mass. This is how the wheel is statically balanced.
The cause of dynamic imbalance is the imbalance in the width of the wheel. It manifests itself only in the process of its rotation. This leads to a shift in the axis of inertia and the axis of rotation. The rotation of such a wheel is accompanied by the emergence of centrifugal forces. Elimination of dynamic balance is possible by fixing balancing weights. Dynamic balancing is carried out on a special installation.
The causes of dynamic imbalance, in particular, include:
- valve hole in the disk;
- wheel shape error;
- the presence of inhomogeneities in the material.
home cause of wheel wobble and unbalance - the heterogeneity of the tire, because it is at the greatest distance from the axis of rotation. In addition, it has a greater mass and complex structure. It includes various materials: rubber, fabric, steel wires. The farther the particle is from the axis, the more it affects the imbalance.
Beating at speed
Why is it happening wheel shaking at speed? We single out the three most characteristic modes of vehicle movement:
- at low speed;
- at high speed;
- when braking.
Wheel wobble at low speed may be due to a number of reasons. Among the main factors are:
- the presence of bumps, bulges, bumps on the tire;
- rubber wear from the inside;
- various disk damage;
- wheel imbalance.
Beating at high speeds is a consequence of imbalance. When pieces of dirt stick to the wheel, the balance is disturbed. This is often observed after driving on a dirt road. Under the influence of adhering snow or ice, the same thing happens. Another reason is also possible. The formation of pellets inside the tire.
Wheel wobble when braking possibly due to:
- unbalanced wheels;
- destroyed bearing;
- worn brake discs.
Front wheel runout feels stronger. Driving out of balance is not safe. In addition to vibration, tires, wheels, suspension elements wear out. The vehicle may lose stability, resulting in an accident.
Rear wheel wobble affect driving stability to a lesser extent. People often ask: "Do I need to balance the rear wheels?". Necessarily! The imbalance here also leads to uneven tire wear. The consequences of the beating of the rear wheels are no less detrimental. Discs and suspensions are rapidly destroyed. Therefore, they cannot be ignored.
Every driver has encountered vibrations and bumps on the steering wheel while driving, in many cases the beating of the wheel is to blame, or rather its incorrect balancing. The wheel must be in perfect shape. Size and other factors may also play a role. But, most often the problem is solved by simple balancing. Let's look at what balancing is, what it is and how to do it correctly. 
Wheel beating - what is it. Types of wheel runout
Wheel runout - disc displacement during movement, can be radial or axial. Either way, you'll get vibration or bumps. The higher the speed, the more noticeable the problem becomes.Consider the varieties in more detail.
- Axial runout is the horizontal displacement of the wheel. Usually such behavior of a disk is called "eight". Usually caused by an imbalance in the distribution of mass on the plane.
- Radial runout is caused by static imbalance. At the same time, the disk begins to resemble an egg in shape. Oscillatory movements occur up and down. Usually accompanied by variable torque.
It is worth considering what may be the consequence of such a phenomenon. With axial runout, the main consequences are the following:
- damage to the steering gear and chassis;
- increased wear of the tread, which leads to a rapid failure of the tire.
It is also worth separating dynamic and static imbalance. There are some peculiarities here, first of all, by the method of fixing the problem.
In static imbalance, torque is generated by the weight of the unbalanced mass. Simply put, the wheel will rotate without interference until the unbalanced mass is in its extreme position. Thus, the movement of the rim resembles a pendulum.
In the case of dynamic imbalance, the rim has an imbalance in width. You can only watch while spinning. In the case of such a problem, the axis of rotation is completely out of alignment with the main central axis of inertia. In fact, a certain angle is formed between the axes. At the same time, the presence of two centers of mass in different parts of the wheel causes a dynamic imbalance. During movement, centrifugal forces arise, they act in opposite directions and manifest themselves in the form of a beating wheel.
How does the wheel beat
In practice, the driver most often notices a beating on impacts when driving. Moreover, the wheel starts to beat even on a flat road, and the higher the speed, the more intense the blows. In many cases, the beat begins in the steering wheel, which may begin to vibrate. The car becomes less manageable.
The relationship between speed and beat amplification is explained by a simple reason. The imbalance has a certain period, for example, two meters. The faster the car moves, the more often the cause of the beating repeats, respectively, the higher the speed, the more noticeable the problem. Also affects the amount of imbalance.
In some cases, it may occur during braking. Here we are talking more about the static imbalance of the wheel. Vibration of the wheels when working with the brake is often evidence of this. The cause is often the destruction of the hub bearings or problems with the brake mechanism.
Separately, it is worth analyzing the reasons for the appearance of imbalance. Let's list the main ones.
- Mechanical damage and deformation of suspension parts. In fact, the wheel consists not only of a disk and a tire, there is a hub, a brake caliper and a disk. If they are deformed, this can also cause wobble.
- Deformation of the rim. During operation, a change in the geometry of the disk may occur.
- Uneven tire wear. First of all, we are talking about tread wear within one wheel. But, in practice, there is also a problem with uneven tire wear on different wheels of the same axle. If one wheel has more than 1.5mm of pattern wear, this will also cause wobble.
- Wrong wheel change. In fact, the reason is quite common. Drivers often when installing a spare wheel, the final tightening of the wheel is done after lowering the jack. This can cause the disk to shift by millimeters relative to the axis, respectively, a beating appears.
How to check a wheel for runout
An important point is the diagnosis of this phenomenon. The difficulty lies in the fact that tire runout is very difficult to diagnose. Noticeable impacts occur only at a high level of violation. Therefore, it is recommended to check periodically. Be sure to check both the rear and front wheels. It is especially important to carry out this diagnosis if you change tires, or if there is any vibration on the steering wheel.
If there is a suspicion not a beating of the wheel. First check for geometric imbalance. To do this, the wheel of the car is hung out, and when scrolling with a special device, the level of the beat is measured. If the parameter exceeds 0.5 mm, the cause should be identified and eliminated. After checking the presence of a geometric imbalance, it is worth removing the wheel and balancing on a special machine. This should eliminate the beating almost completely.
The consequences of a beating wheel
The most obvious consequence of runout is rapid tire wear. They begin to wear unevenly, which worsens their technical characteristics.
Another point that is less obvious is damage to the suspension and steering. The beating is characterized by impacts on the elements of the chassis associated with the wheel, as well as on the steering mechanisms. This leads to their rapid failure.
Another possible problem is the deterioration of controllability. With strong impacts, there is a risk of losing control of the car. The result can be an emergency on the road.
Unbalance and runout of alloy wheels
In the manufacture of alloy wheels, there are many features that affect the imbalance. If for checking on a balancing machine to determine a defect according to the Russian standard (GOST R 50511-93) there is no acceptable imbalance value, then in practice we support the internal standards of wheel rim manufacturers. These enterprises are suppliers of disks to conveyors of world and Russian car manufacturers, and their internal standard can be applied to disks supplied to our automotive market. In order to avoid the imbalance situation, our company has decided to inform the buyers of the imbalance limits.
There are several types of runout: radial and axial. Radial runout is the deviation of the center relative to the base axis. The radial runout of the disc should not exceed (0.7mm). Axial runout is the beating of the disk along the axis (figure eight). The axial runout of the disc should not exceed (1mm).
If an unacceptable runout of a new disc is detected, an act on a factory defect is drawn up, and the disc is returned to the manufacturer for inspection and replacement with a disc of good quality in accordance with the Russian standard GOST R 50511-93.3. In this case, the buyer does not bear any costs for replacement with a disk of proper quality.
Also, during the operation of tires and disks, such moments appear when external factors affect the beating of the steering wheel. This sticking to the inner part of the disk (dirt and ice), the steering wheel beating appears at a speed (from 80 to 120 km / h), which is eliminated by washing the wheel and subsequent rebalancing.
Also, the deformation of the disk and tire affects the balance, as a result of jamming of the disk and the appearance of a hernia on the tire, an imbalance of the entire wheel occurs and discomfort when driving.
An imbalance can also be such a factor as incomplete fit of the tire to the disk during installation and subsequent incorrect balancing, this is due to the low qualification of tire mangers. To properly seat the tire on the rim, a special mounting paste must be used and for a full fit of the bead ring of the tire to the rim of the rim, excess pressure in the tire during installation, as well as a special tool for mounting a low-profile tire or a tire with a reinforced sidewall (RunFlat), is required. As a rule, low-skilled workers work in a conventional (roadside) tire and a good quality of work can not be expected, therefore we recommend contacting trusted or well-known tires with qualified workers, because many employees of the tire are not even aware of the elementary designations on the tire such as outside (outer side of the tire) and inside (inner side of the tire), as well as color markings (red, yellow, green and white) on the bead, which are indicated by the manufacturer for ease of mounting and balancing, for example (yellow) dot indicates the easiest place in the tire and it must be combined with the valve in the disk for better optimization, and the red dot indicates the heaviest place in the tire and it must be placed opposite the valve in the disk, also the most experienced C/M workers do optimization by scrolling the tire on the disk to reduce imbalance.
Also, wheel runout can be influenced by such a factor as incorrect selection of a disk for a particular car, for example, a mismatch between the central hole of the disk to your car, which will lead to a displacement of the disk on the vehicle axis, which will lead to steering wheel beating, as well as unscrewing the fasteners of the disk on vehicle, which could result in an ACCIDENT. Here we have given only a small part of what can affect the imbalance and runout of alloy wheels, but our managers will help you in a qualified selection and solving problems with emerging issues.
An experienced driver is able to determine the presence of problems in his car by its behavior or sound.
Shaking the car during acceleration or at a specific speed is a sign of a serious problem. Service station workers assure that in 9 out of 10 cases the cause vibration body or steering wheel runout are wheels.
Reasons for the emergence of vibrations in the wheels may be different, but you should not delay with their elimination, otherwise more serious problems will soon arise.
Chassis and wheels
If you felt vibration that has arisen from the bottom of the car, keep in mind that there can be at least two reasons.
1 - wheels
2 - running gear.
In the first case, you will be able to diagnose the problem yourself. The most common and stupid reason that negatively affects your safety is not fully tightened bolts for mounting disk wheels. Tighten them as quickly as possible, and the problem is solved.
Also the culprits of the appearance of bad vibrations in the wheels I can be:
- wheel imbalance, which may appear after falling into a pit, poorly done balancing, long parking on a flat tire, etc.
- mud or snow accumulated on the rim. One way or another, they also have weight and may well give vibration.
- geometry violation disk or tire.
But much more often there are more serious problems.
The cause of vibration of the wheels or the body can be: 
- Poor fixation of the brake disc;
- Bending of the drive shaft of the wheel;
- Bearing damage;
- CV joint damage.
It is the problem with CV joints that occurs most often. To independently check their serviceability, you need to raise the car with a jack and turn the wheel. If you hear extraneous sounds like clicks or a crunch, then most likely it's time to change the CV joint. If, in addition, there is a play exceeding 2 mm, then the replacement of the CV joint is mandatory. It is also necessary to check if dust, dirt or water has entered the CV joint. After that, the bodywork should disappear.
Additionally, it does not interfere with inspecting the anthers for gaps in their rubber part.
Wheel alignment and tire quality
Appearance vibration may also be due to incorrect wheel alignment. In this case, the vehicle may pull to the side and the wear of the rubber becomes uneven, which will lead to the costs associated with its replacement.
You can troubleshoot these issues in a variety of ways.
First you need to adjust the installation angle wheels with the help of collapse-convergence. It may turn out that the disk itself is damaged due to a strong impact. After replacement or repair vibration will disappear.
Do not forget that after all these procedures, wheel balancing is necessary. Unfortunately, many motorists neglect it.
The above breakdowns are classified as easily repairable and inexpensive, so it is worth starting the diagnosis with their identification.
If this does not help, and continues, we deal with the problem further.
Engine mounts, traction and other problems
If you feel strong, accelerate the car a little more than usual. If in the process of increasing turnover vibration increases, then its cause may be a breakdown of one of the engine mounts.
Also cause wheel vibration could be a gearbox failure. If the car starts to shake more at a speed of 80 km / h or more, then try to diagnose the presence or absence of this problem as follows:
- Accelerate the car up to 85 km/h;
- Depress the clutch pedal and listen for vibration sounds;
- Engage third gear and gently release the clutch, not forgetting the gas pedal.
If during these steps wheel vibration not gone, the box has nothing to do with the problem. And it’s good, because its replacement or repair is quite expensive.
If the shaking becomes stronger, then you will need to check the involvement of the box in the problems with professionals at the service station.
For automatic transmissions, you can check the box in the same way. Only instead of third gear and clutch, switch modes in the following sequence: 3, 2, D, N and listen to the vibration sounds.
If, in the course of the independent actions taken, it was not possible to identify the problem, and it continues, specialized help from professionals will be required.
It is not worth saving, because even the smallest breakdown can lead to serious consequences and costly repairs. And above all, do not forget about your safety and the safety of your passengers.
Results
If the problem could not be detected, and during acceleration, the presence of vibration of the body or the steering wheel of the car is still noted, then there is only one way out - contact a specialist. This problem should not remain, as it can cause more complex breakdowns or a dangerous situation for the driver and passengers of the car while driving on the road. It is necessary to respond as quickly as possible to all possible problems in order to eliminate them by replacing the elements of the machine that are out of order.
And the specialists of the company "Shinomontazhnikof" are ready to come to your aid at any time of the day and as quickly as possible to fix the problem right at the site of your car breakdown. All the necessary equipment is always with you.
The company "Shinomontazhnikof": quality and affordable prices 24/7!
