End (axial) runout of the wheel occurs during rotation and looks like the oscillatory movement of the humps wheel rim in a plane parallel to the axis of rotation.

Radial runout occurs in similar conditions, but means oscillatory movement of the rim in a vertical plane.

In the figure on the left, you can see a schematic representation of both types of beats.

High end runout values ​​are often the result of wheel impacts from a side curb collision. Sometimes this can be seen when the jeep skids on a slippery road. The exceeding value of the radial runout appears as a result of a strong frontal impact on the wheel, that is, in a collision with a pothole or a pit. But more often than not, a "good" hit will result in both beats. In pronounced cases, the steel disc gets crushed on the rim flanges, chipped and visible to the naked eye "eight" when rolling.

What is considered an excess?

In accordance with the domestic standard GOST R 50511-93, the runout of a passenger car rim in the area of ​​the tire (humps) should be no more than 0.5 mm in any kind of runout. This standard also applies to SUVs.

Do not try to establish the amount of beating of the steel disc visually, as in this case, vision will not allow you to accurately estimate the size of the deviation. In some cases, with such small beats as 0.3 mm, the average person is convinced of its exorbitant size. For accurate measurement, a clock or electronic indicator should be used, which is located on the axis of symmetry of the jeep's rim.

The most common causes of beating

A significant part of the causes of the runout is not associated with a change in the geometry of the alloy wheel of an SUV, but relates to production or operational:

• Uneven paintwork disc mating plane
• Adhered pieces of road surface and dirt
• Debris and foreign matter on the balancer flange

In other words, you don't always have to blame yourself or the previous owner of the car for an unacceptable amount of heartbeat. The reason may be more prosaic and does not require large investments for its elimination.

Serve round!

The car shook - do not panic: it happens that it is easier to eliminate the cause than a steamed turnip. For example, when driving on flat asphalt, the steering wheel vibrates. The wheels are always to blame! Especially if a car with easy rack and pinion control - for example, a front-wheel drive VAZ. The wheel should be treated as "you": the faster it spins, the more stringent the requirements for the accuracy of its shape, the quality of balancing and installation. If the balancing is "C", when the wheel rotates, the inertial force of the "hard place" causes shaking. And then simple arithmetic. Let's say the wheel travels 2 m in one revolution, but it shakes the hardest by only 90 km / h (25 m / s). This means that the resonant frequency of vibrations is 12.5 Hz ... Remember: the steering wheel can only calm down the jewelry balancing of the front wheels. Not everyone and everywhere do it carefully, so look for experienced craftsmen.

The vibration pattern is not always straightforward. If only one wheel shakes, then everything depends on its imbalance and rotation speed. The maximum is all at the same resonant speed. But if every time after turning the road the steering wheel shakes differently than before it, then both front wheels are out of order. The paths they have traveled in the corner are different - the mutual position of the "difficult places" and their effect on the steering wheel change. If you drive circle after circle along the track at a constant speed, the vibrations will increase and decrease.

But sometimes this happens on a straight highway. And few people guess about the reason - these are poorly balanced wheels ... different sizes! The explanation is elementary: here you have replaced a wheel with a tread worn by 1.5 mm with a fresh spare tire. If the spare wheel passes the same 2 m per revolution, then the working wheel is 1.9906 m. With each revolution, the "heavy place" of one wheel is shifted relative to the other - and the vibration portrait of the machine will be repeated after 423 m of the way. Of course, the greater the difference in tire sizes, the more frequent the repetitions. Well, all this can further confuse slippery roads! In short, if you don't want puzzles, watch the balancing.

Alas, this is not the only problem. For example, the crankshaft is perfectly balanced, and the deformed wheel, no matter how balanced it, continues to shake violently. Ride on such a "wheel" - thank you! Serve round. Let us compare (Fig. 1, a, b) the behavior of a deformed wheel on a smooth surface and a serviceable one on a bumpy one. If the bump on the tire reproduces the length and height of the bump on the surface, then the trajectory of the wheel axis during slow motion is the same. At high speeds, there may be some nuances, but still shaking from the curve of the tire is inevitable.

How do you know on the go if a wheel or tire is crooked? If the steering wheel gently drives or the body shakes at speeds of 5-10 km / h, when the role of imbalance is negligible, then at least one wheel is damaged. Everything that was said above about variable shaking in corners, etc., is also true for crooked wheels.

So, balancing alone is not enough for a wheel - it is important that, in contact with the road, the rotating wheel does not have geometric beats - radial, axial and any other. And then, after all, a completely round one, being on a deformed hub, can throw up a riddle. Here's a recent case. The driver felt a shaking of the steering wheel - he put the wheels in balance. Did it - it shakes again. Repeated - again. Came to me. Not without difficulty they found the reason - a bent hub! Therefore, a serviceable wheel was rolling in a zigzag ...

And here typical mistake an inexperienced motorist: hangs up a spare tire instead of a punctured wheel - and lowers the car with untightened bolts - after that, they say, it’s better to tighten! Well, under load, the wheel will move upward relative to the hub, as far as the clearances allow. If the bolts are tightened now, friction will prevent the wheel from centering - and it will rotate with an eccentricity e (Fig. 2), acquire an imbalance and hit it along the road with an amplitude of 2e.

It is correct to start not with balancing, but with adjusting the geometry: the radial and axial geometric runout of the tire should be as small as possible. Only then go to balance.

Terminology

A complete wheel is a wheel with a tire mounted on it.

A wheel is a rotating element of a car that transmits torque and receives a load from the mass of the car. The wheel is located between the tire and the hub.

A tire is a resilient air-filled shell designed to be mounted on a rim.

The wheel of a modern passenger car, as a rule, consists of non-separable elements: a disc and a rim.

The wheel disc is the part of the wheel that is the connecting element between the vehicle hub and the wheel rim.

The wheel rim is the part of the wheel on which the tire is mounted and supported. Different parts of the rim have specific names:

Rim flange - the part of the wheel rim that forms the side stop for the bead of the tire.

Rim landing flange - the part of the rim designed to accommodate the base of the tire bead.

Hump ​​- an annular protrusion on the rim, which prevents the toe of the tire bead from sliding off the landing shelf and depressurization of the tubeless tire under load.

A mounting groove is a part of the rim that has a width and depth sufficient for mounting and dismounting the tire bead through the bead flange of the rim.

The main elements of the tire:

- protector

- sidewall

- hermetic layer

To the consumer

1. Make sure that vehicle vibration occurs on different types of roads and that it is not related to ruts and unevenness on the road ( road markings, change of road surface types, minor irregularities on the road ...)

2. Inspect the wheels - clean the wheels from dirt, wash them, especially from the inside. Inspect wheels for damage. Examine the tires carefully - remove any stuck objects from the tread pattern: stones and other objects.

3. Check the level of tightening of bolts / nuts or other fasteners of the wheels, make sure that the tightening torque is not loose.

If necessary, tighten the bolts yourself or contact a tire shop.

4. Inspect the wheels for any missing balancing weights. If you find that the goods have been lost, notify a specialist tire changer or auto mechanic.

5. Check the inflation pressure in the tires. The pressure should be checked and set only on cold tires (i.e. not immediately after prolonged continuous use) and it should be in accordance with the recommendations of the car manufacturer (see the factory information tag (sticker, sticker), which is usually located on the fuel filler flap or in the driver's doors).

6. If all of the above actions did not eliminate the vibrations, you should contact the tire shop. Try to determine which wheel is the source of vibration. Give this information to a specialist tire changer or car mechanic.

8. After tire fitting, exclude sudden starts and emergency braking from your driving style for a period of one week from the date of tire fitting in order to avoid turning the tire on the wheel.

INFORMATION SHEET:

The vibration of the steering wheel or car can be caused by the characteristics of the tires or by other reasons

Causes of wheel beating

For a specialist

1. Check with the consumer - which wheels are the source of vibrations? When are vibrations felt?

2. Check the inflation pressure of all tires.

3. Thoroughly clean the wheel assembly from dust, dirt and other foreign matter.

4. Determine which wheel assembly is the cause of vibration - for this, evaluate the vibration with the driver at the current wheel alignment, rearrange the wheels on the car and analyze the changes. As a rule, vibrations are caused by one, rarely two wheels, and not all four. When the wheel (s) have been identified - inspect it (s)

4.1 Remove the wheel (s) assembly suspected of being the vibration source from the vehicle

4.2 Check the wheel assemblies for residual imbalance. Residual imbalance should be no more than 5 grams per side.

4.3 Check the level of radial and lateral runout of all removed wheel assemblies. The radial runout should be no more than 1.5 mm (total average value). The runout level should be measured exclusively with a meter on a balancing machine or dial indicator. Do not use "by eye" assessment.

4.4 Check the shrinkage of the tire on the rim. Bead trim should be evenly spaced from the rim flange.

4.5 Check the condition of the wheels ("disks") - the wheels should not be damaged: dents, cracks, traces of welding or repair.

4.6 Check the condition of the wheel surface in the part where the wheel rests on the vehicle hub (mating plane) - there should be no traces of corrosion, dirt, varnish, paint and other foreign substances on the mating plane.

4.7 Check the car hub - the hub must be clean: free of rust, dirt and other foreign matter.

4.8 Check the condition of the wheel center hole - it should be smooth, free from damage, dirt, corrosion, paint and varnish deposits, and other substances. The center bore of the wheel must be exactly dimensioned for the hub, or spacer rings of the correct size must be used.

4.9 Fitted wheel center bore spacers (if any) must be sized to fit, fit snugly, clean and free of damage.

4.10 If any foreign substances are visible on the mating plane, the center hole of the wheel or the hub of the car - remove them with a brush or other cleaning tools and means.

4.11 Check the condition of the tires - there should be no signs of significant repairs on the tires, no noticeable damage (swelling, cuts), foreign objects in the tires (stones, etc.)

4.12 Check the fasteners. Nuts / bolts must match: the size of the thread - the car; by the type of fastening surface (cone, sphere, plane) - to wheels; along their length, the nuts / bolts must be tightened at least 6 - 8 turns until they are fully tightened; threads must be clean, free from dirt, threads free from bumps and burrs.

5. When you have determined which wheel assembly is the cause of vibrations - make a mark on the tire about the valve position and dismantle the tire and inspect:

5.1 Check the condition of the wheel rim - there should be no traces of corrosion, dirt and other foreign substances on the rim (especially on the rim edge, landing shelf, hump and near it). If there are any substances on the rim, remove them with a brush and / or other means.

5.2 Check the condition of the rim for damage: there should be no dents, cracks, traces of welding or repair, geometry correction. Using a damaged wheel may cause vibrations.

5.3 Measure the runout level of the rim flange. The radial and lateral runout of the wheel rim landing flange should not exceed 0.5 mm. The runout is measured only by an indicator on the balancing machine or a dial indicator.

5.4 Remove any installed balance weights and measure the wheel unbalance (without tire). Note that significant imbalance in the wheel can cause vibration.

5.5 Check the condition of the tires - there should be no traces of significant repairs on the tires, traces of driving with reduced pressure, damage to the bead and hermetic layer. Using damaged tires can require large amounts of balancing weights, vibrate and be hazardous!

6. Reinstall the tire onto the rim.

6.1 Before mounting, apply a thin, even coat of specially formulated grease to the rim and tire. On the rim, the grease should completely cover the rim landing flange, hump, with a thin layer. On the tire, the grease should cover both beads of the tire. The lubricant should be applied in a thin layer and should not be applied in excess to prevent the tire from spinning on the wheel. Avoid getting grease on the sidewall of the tire.

6.2 Tire inflation should be done in two stages. First, inflate the tire without a spool to 4 atmospheres of overpressure until the tire shrinks completely on the rim, then release the overpressure, insert the spool and bring the pressure to the required level. Inflation in two stages allows the tire bead to be stretched better and to sit flat on the landing bunk.

6.3 Caution: When inflating the tire, do not stand on the sidewall of the tire. Always stay only on the side of the tread (!)

6.4 Check the shrinkage of the tire on the rim. Bead trim should be evenly spaced from the rim flange. If shrinkage has not occurred completely, dismantle the tire, find the cause of incomplete shrinkage (incomplete greasing, dirt, rim defects: repair, jam ...), eliminate this cause and re-inflate the tire until complete shrinkage.

7. Remove the wheel assembly from the tire changer and tap it on the floor for better bead shrinkage on the rim. Only then should the wheel be installed on the balancing machine.

10. Before installing the adhesive-type weights - bend them and shape them into the back of the rim. The place for the installation of weights should be additionally cleaned and degreased. Install weights. After installation, the weights should be additionally secured with a few blows with a hammer.

11. Mark a spot on the tire next to the tire inflation valve. If, after some time, this mark moves relative to the valve, this will be evidence of the wheel turning inside the tire. In this situation, the driver's attention should be paid to the manner of driving, as well as to reduce the amount of lubricant applied during tire fitting.

12. Place the wheel assembly onto the vehicle in its place.

13. Additionally, make sure that the real direction of rotation and the specified by the tread pattern match.

14. Check fasteners. Nuts or bolts must match: by thread size - car; by the type of fastening surface (cone, sphere, plane) - to wheels; along their length - nuts or bolts must be tightened at least 6 - 8 turns until fully tightened; threads must be clean, free from dirt, threads free from bumps and burrs.

15. Lubricate the fasteners with a drop of engine oil or a little grease.

16. Tighten the bolts by sequentially tightening the opposite bolts from the center hole.

17. Tighten the bolts with a torque wrench to the required torque for the type of wheel.

Consistent and careful execution of these actions eliminates the origin of vibrations associated with tires and tire fitting work. If, as a result of operations, vibrations remain, then you should check technical condition car.

* "FIT (OPTIMIZATION)" - the procedure for optimal alignment of the tire and rim, taking into account their

features. The fit can be directed towards 1) reducing the level of runout of the wheel assembly

2) reducing the number of installed loads to eliminate the imbalance. "Trim (Optimize)" to Reduce Runout and Reduce Vibration:

18. Measure the level of radial runout of the rim (without tire) - find the place with the most low level rim (closest to the center of the axis of rotation); mark it on the inside of the rim so that after mounting the tire - this place is clearly visible

19. Install the tire, inflate the tire and measure the tire radial runout. Where tire runout is greatest (further from the center of rotation) - make a mark on the tire.

20. Deflate the tire, remove the tire beads from the landing bench and rotate the tire and wheel to align the marks. Align the marks on the rim and on the tire so that they are on the same virtual line towards the center of the circle.

21. Inflate the tire in two stages, making sure the tire is correctly seated on the rim flange. Bead trim should be evenly spaced from the rim flange. If shrinkage has not occurred completely, dismantle the tire, eliminate the cause and re-inflate.

Compliance with the alignment of the marks will give the lowest level of radial runout and a decrease in possible vibrations of the vehicle.

If the car pulls to the side

To the consumer

3. Check the direction of rotation of the tires. Is the direction indicated on the tire correct? If tires with non-directional tread pattern are installed, make sure they are installed with the outside (production date) facing out (away from the vehicle).

4. Inspect the tires - do all tires have the same residual tread depth? A significant difference in the tread depth of the tires on one axle can cause the vehicle to slip to the side.

5. Check that the installed wheels (disks) and tires comply with the requirements of the car manufacturer's factory.

6. Make sure that the drift occurs on different types of roads and that it is not related to ruts on the road, the slope of the road surface or the distribution of loads on the vehicle or trailer.

7. Check the level of tightening of bolts / nuts or other fasteners of the wheels - it is possible that the tightening torque is weak.

8. Check the technical condition of the vehicle: wheel alignment parameter, condition brake system general condition of the chassis of the vehicle.

9. If the above steps do not fix the problem, you should contact the tire shop.

10. Establish when the vehicle is drifting: when accelerating, when driving at speed, when coasting, when braking or other options - inform a tire specialist or auto mechanic.

INFORMATION SHEET:

The phenomenon when the car pulls to the side can be caused both by the peculiarity of the tires and by other reasons:

Materials used (wheels, fasteners ...)

The quality of tire fitting works,

The quality of work on installing the wheel assembly on the vehicle

Technical condition vehicle(the condition of the car's hub, the condition of the chassis, the vehicle's braking system ...)

And also other reasons not related to tires

To find out the real reason, you should contact a specialized tire workshop or an experienced auto mechanic.

SPECIALIST-TIRE MANAGER OR AUTOMOTIVE

1. Check the inflation pressure of all tires.

2. Make sure tires of the same size, model, construction and tread pattern are installed on the same axle of the vehicle.

3. Check the direction of rotation of the wheel and match the tread pattern of the tire.

4. Check tire wear and residual tread depth. A significant difference in residual tread depth or a difference in the type of tire wear can cause the vehicle to slip to the side.

5. Check the compliance of the installed wheels (disks) and tires with the requirements of the car manufacturer.

6. Carry out rotations (change of mounting locations) of the wheel assembly on the car and determine the influence of the position of the tires on the degree of "slip" of the car. As a rule, the cause of a car drift is one, less often two wheels, and not all four.

7. Compare with other tires and determine if tire fitting is associated with drift, and if so, which tires?

8. Check the shrinkage of the tire on the rim. Check wheel runout and balance. If necessary, re-dismantle / mount / balance - see above.

If, based on the result of tire rotations and the use of other tires for comparison, it was not possible to establish which tires are the cause of the car drift, then the technical condition of the car should be checked: the camber-toe parameter, the state of the brake system and the car's suspension, steering, as well as other systems and units of the vehicle.

What to do if “a lot” of weights were required for balancing

To the consumer

1. Check the inflation pressure in the tires. The correct pressure should be set on cold tires (not immediately after extended periods of continuous use) and should be in accordance with the vehicle manufacturer's recommendations.

2. Inspect the wheels - clean the wheels from dirt, wash them. Inspect wheels for damage. Examine the tires carefully - remove any stuck objects from the tread pattern: stones and other objects. Remember that foreign objects: dirt, stones, excess rim repair material, self-installed decorative elements on the wheels can cause increased imbalance, which requires the installation of a relatively large number of weights for balancing.

3. If you have any additional questions - contact the tire shop.

5. After tire fitting, exclude sudden starts and emergency braking from your driving style for a period of one week from the date of tire fitting.

INFORMATION SHEET:

Balancing weights are used in tires to balance the wheel mass and rotate them evenly, without vibrations. The amount of weights required to balance a wheel depends on both the level of tire imbalance and the imbalance of the rim used, the quality of the tire shrinkage on the rim, and the quality of the tire fitting. The amount of balancing weights, if properly installed, does not affect the performance of tires and the vehicle as a whole.

The number of goods glued (by the type of fastening) to the rim is not standardized by the general standards of GOSTs and other standards, only the number of rammed / clamped (by the type of fastening) loads is normalized.

For a specialist

The amount of weights required to balance the wheel depends on the imbalance of the wheel, the unbalance of the tire, the measurement error of the balancing machine and the quality of the tire fitting. To reduce the amount of weights required for balancing the wheel assembly, you should use "adjustment (optimization)", which can be done in two main ways:

1. Thoroughly clean the complete wheels from dust, dirt and other foreign matter.

2. Bleed the air from the tire, dismantle it and inspect the wheel more carefully:

2.1 Check the condition of the wheel rim - on the rim (especially on the landing shelf and hump) there is no

but be traces of corrosion, dirt and other foreign matter. If there are any substances on the rim, remove them with a brush and / or other means.

2.2 Check the condition of the rim for damage: there should be no dents, cracks, traces of welding or repair, geometry correction. Using a damaged wheel has unpredictable consequences and may require the installation of a large number of weights.

2.3 Measure the runout level of the rim flange. The radial and lateral runout of the wheel rim landing flange should not exceed 0.5 mm. The runout is measured only by an indicator on the balancing machine or a dial indicator.

2.4 Remove any installed balancing weights and measure the wheel unbalance (without tire).

3. Install the wheel without tire on the balancing machine

4. Measure and set the required amount of balancing weights so that the wheel (without a tire) has a residual unbalance of no more than 5 grams per side

5. Check the condition of the tires - there should be no traces of significant repairs on the tires, traces of low pressure driving, damage to the bead and hermetic layer. Using damaged tires can require large amounts of balancing weights, vibrate and be hazardous!

6. Mount the tire on the rim, fix the wheel assembly on the balancing machine using flange and collet adapters. Flange and collet adapters are special devices that center the wheel position on the balancing machine.

(For example, the HAWEKA device Attention!

The adapters used must be free of deformation and signs of significant wear.

7. Using the program for measuring static unbalance, - find the lightest place of the wheel assembly and mark it on the tire with chalk or felt-tip pen (marker).

8. Bleed the air from the tire, remove the installed balance weights from the rim.

9. Insert the tire beads into the rim mounting groove and rotate the tire over the rim to align the chalk mark on the tire and the valve. Align the mark on the tire and the valve so that they are on the same virtual straight line towards the center of the circle.

10. Inflate the tire in two steps, making sure the tire is correctly seated on the rim flange.

11. Observing the alignment of the valve and the mark will allow the heaviest part of the rim to be connected to the lightest part of the tire, thus reducing the amount of weight required to balance the wheel.

1. Place the tire on the rim, inflate the tire in two steps, make sure the tire is properly seated on the rim flange, and mount the wheel assembly to the balancer using flange and collet adapters.

2. Mark the mark with the number 1 on the outer sidewall of the tire so that this mark is on the same virtual line with the valve and the center of rotation of the wheel assembly on the machine.

3. Turn the wheel assembly on the machine 180 degrees and on the same outer sidewall of the tire set another mark with the number 3 so that the mark is on the same virtual line with the valve and the center of the circle.

4. Next, rotate the wheel assembly at an angle of 90 degrees and make two more marks on the sidewalls numbered 2 and 4 so that the virtual line connecting the two marks numbered 2 and 4 is perpendicular to the virtual line connecting the marks numbered 1 and 3.

5. As a result, there should be 4 consecutive marks on the sidewall of the tire, identical to positions 12, 3, 6 and 9 as on the dial of a mechanical watch. The position of the wheel inside the tire using these marks will be determined by the tire valve.

6. First measure the dynamic unbalance * of the wheel assembly with the valve position next to the number 1 mark. Record the values ​​marked “1”

7. Remove the wheel from the balancing machine; bleed the tire; remove the tire from the landing shelf; turn the tire by aligning the wheel valve with the mark 2 on the tire; inflate the tire in two stages; make sure the tire is correctly seated on the rim shelf; install the wheel assembly on the balancing machine; measure the dynamic unbalance and record the values ​​marked with 2.

8. Repeat the described actions with marks 3 and 4. Compare the obtained values ​​and choose the optimal one.

9. For most situations, it is enough to choose one of four positions

10. In exceptional cases, further adjustments can be made. To do this, it is necessary to reduce the distance between the marks, take measurements and find the most optimal value... Compliance with these recommendations, as a rule, allows you to reduce the amount of weights required for balancing. It should be borne in mind that there are unbalance tolerances for each tire size. In addition, please be aware that at the time of this writing

on the territory of the Russian Federation, there are no uniform tolerances for the mass of correction weights separately for wheels. Accordingly, the implementation of these recommendations will give the most optimal value of correction weights, however, it will not always be able to eliminate it completely.

4. What to do if you can see that the tire has a runout (has an "egg" or "eight" shape)

1. Check the inflation pressure in the tires. The pressure should be checked and set only on cold tires (i.e. not immediately after prolonged continuous use) and it should be in accordance with the recommendations of the car manufacturer (see the factory information tag (sticker, sticker), which is usually located on the fuel filler flap or in the driver's doors).

2. Do not try to visually assess the tire runout. It is not right. The human eye is not the most accurate instrument, and visually a beat of 0.3 mm is perceived by a person as critical, although in fact it is not. Only measurement with the help of specialized means can give an exact value.

3. Contact a tire shop to measure the runout.

4. Evaluate - whether the detected beating causes any inconvenience: steering wheel vibration, car body vibration, uneven tire wear, car drifting to the side ... Give this information to a tire changer or auto mechanic.

5. Inspect the tires for wire strands coming out of the solid rubber compound and for internal lamination of the tire. If you find something - contact the tire shop and inform the tire changer or auto mechanic about it.

6. After tire fitting, exclude sudden starts and emergency braking from your driving style for a period of one week from the date of tire fitting.

For a specialist

1. Check the tire inflation pressure.

2. Inspect the tires for wire strands coming out of the solid rubber compound and for internal lamination of the tire.

3. Measure the tire radial and lateral runout. Radial runout should not exceed 1.5 mm, lateral runout 2 mm.

4. If the measured values ​​meet the specified limits and no delamination or wire breaks were detected, then everything is in order and you can continue to operate.

5. If the measured values ​​meet the specified limits, then check the condition of the wheel and tire according to the scheme described in section 1 from external inspection to re-fitting and balancing (points 1 to 19).

1. Exceeding the permissible values ​​of disk imbalance

Due to the nature of the casting process, all alloy wheels have more or less imbalance. Balancing machines are designed specifically to equalize the total imbalance of a disc assembly with a tire, and even the largest unbalance, after alignment on a balancing machine, does not have any negative effect on the car's mechanisms and does not reduce the comfort of driving. Since the imbalance of the wheel assembly can change during operation (dirt adhesion on the inner rim of the rim, tire rotation on the rim, the appearance of hernias on the tire, change in the geometric shape of the rim), we strongly recommend balancing the wheels at least before each operating season.

Insofar as Russian standard (GOST R 50511-93) does not specify the amount of permissible imbalance, then in practice they are usually guided by the internal standards of the manufacturing plants wheel rims... These enterprises are suppliers alloy wheels on conveyors of world car manufacturers and, in our opinion, their internal standard can be extended to discs supplied to the Russian market.

In order to avoid controversial situations associated with a high (in the opinion of the client) disc imbalance, our company has decided to bring to the attention of buyers the limit values ​​of the unbalance for alloy wheels made of light alloys (Table 1).

The numbers in the table are the maximum weight padded (spring) weights... The mass of self-adhesive loads currently common will exceed the limit values ​​indicated in the table, which is not manufacturing defect since the change in mass occurs due to a change in the radius of the sticker of the weights (Fig. 1).

Fig. 1 Change in the mass of weights depending on their location on the example of one 14 inch disk (alternately: padded, self-adhesive and "one weight" mode)

2. Runout (radial and axial)

Disc runout refers to oscillatory displacement landing shelves under the tire when the disk rotates: parallel to the wheel radius - radial, parallel to the wheel rotation axis - axial (end) (Fig. 2). Oscillations during rotation of the outer rims of the disc, mounting strand or the face of the disc are not considered to be a runout and does not affect performance characteristics no influence.

Rice. 2 Direction of radial and axial beats relative to the axis of rotation of the disc.

According to clause 2.7 of the Russian standard (GOST R 50511-93), the runout of the rim in the areas adjacent to the tire for passenger cars, should not exceed 0.5 mm (Fig. 3)

Rice. 3 Excerpt from GOST R 50511-93.

The most common mistake customers make when determining disc runout is to visually assess the degree of disc runout on a balancing machine. It is not right. The human eye is not the most accurate instrument, and visually a beat of 0.3 mm is perceived by a person as critical, although in fact it is not.

To check the disc runout, use any indicator, electronic or dial type, on a tripod with a measurement accuracy of at least 0.05 mm. The check is carried out in the middle of the tire seat. The indicator is installed parallel to the radius of the disc when checking the radial runout (Fig. 4), and parallel to the axis of rotation of the disc when checking the axial (end) runout. (Fig. 5)

Rice. 4 Correct and incorrect installation of the indicator when checking the radial runout of the disc

Rice. 5 Checking the axial (face) runout of the disc

The runout is checked exclusively on the inner surfaces of the disc rim !!!

Unfortunately, the most common cause of disc runout on a balancing machine or on a car is not incorrect disc geometry, but some external factors, such as paint overflow on the mating plane, adhering dirt, etc. Remember to carefully check the mating face and center hole before installing the disc on the wheel balancer and on the vehicle. Also check the balancer flange and the mating face with the hub on the vehicle. Any speck, rust, piece of adhesive tape or a small drop of paint on these surfaces can lead to a skewed disc and, as a result, to false runout and a change in the overall geometry of the "tire, disc, hub" set.

Recommended sequence of operations when preparing discs for installation on a car

№	Description of operations	Illustrations
1.	Before installing, carefully inspect the disc for damage (jams on the rim flanges, chips, etc.) that may have formed during transportation or careless storage. Inspect the hub of the car, if necessary, remove dirt, foreign adhered objects and rust, as they can interfere with correct installation wheels on the car.
2.	Check the suitability of the disc on the vehicle: make sure the MAX LOAD (maximum static load capacity) of the disc matches this vehicle make sure that any centering rings are of the correct size and good condition, the disc must sit tightly on the car's hub or with a small gap, the gap between the disc and the suspension and brake system of the car must be at least 2 mm (GOST R 50511-93) Ignoring the applicability and installation rules of the disk will completely void the manufacturer's warranty obligations.
2.a	Check the fasteners to match the vehicle and wheel: - nuts / bolts must match: thread size - car; type of fastening surface (cone, sphere, plane) - discs; its length. - the thread must be clean, free of dirt, the thread of the thread must be free from bumps and burrs; - nuts / bolts must be tightened at least 6 - 8 turns until fully tightened; - the tightening torque of the nuts / bolts is given in the vehicle operation manual and is approximately: thread M12x1.25 - 90 Nm, M12x1.5 - 110 Nm, M14x1.5 - 110 ~ 170 Nm The warranty does not cover damage to the disc or breakage of fasteners due to ignoring the applicability of the fasteners or exceeding the tightening torque of the fasteners.
3.	Install a cone corresponding to the center hole of the disc on the balancing machine stem. Never install a centering cone with front side disk. The hole for the insert is made with less precision than the bore hole and can be made not on the same axis with the axis of the disc bore, which will lead to false runout of the disc on the machine and incorrect disc balancing. Also, when installing the centering cone from the face of the disc, there is a possibility of damage to the paint around the hole for the insert.
4.	Install a disc without a tire on the balancing machine: check the disc unbalance using the rammed (spring) weights, visually check the radial and axial runout of the disc landing flanges, if in doubt, check the disc using an indicator. To achieve the greatest accuracy and quality of balancing, use a method of fastening the disc similar to mounting the disc on a car (Fig. 4 and Fig. 5) Before installing, be sure to check the mating plane and the center hole of the disc for dirt, foreign adhered objects or paint drips. Also check the balancer flange and the mating face with the hub on the vehicle. Any debris on these surfaces can lead to a skewed disc and, as a result, to a change in the overall geometry of the "tire, disc, hub" set.
4.a	To check the radial and axial runout, use any indicator on a tripod with a measurement accuracy of at least 0.05 mm. The check is carried out in the middle of the tire seat. The indicator is installed parallel to the radius of the disc when checking the radial runout, and parallel to the axis of rotation of the disc when checking the axial (end) runout. According to GOST R 50511-93, the maximum allowable runout of the disc landing flange should not exceed 0.5 mm The runout is checked exclusively on the inner surfaces of the disc rim. The ability of some modern balancing machines to measure the runout of the disc on the outer surface of the rim is intended to equalize the runout of the tire and cannot be used to check the runout of the rim landing flanges.
5.	Put the tire on the rim. Place the tire on the rim exactly following the manufacturer's instructions. When installing the tire on a rim with protruding beams, make sure that the pressure foot of the tire changer does not catch the beams as the rim rotates. When using manifold valves, make sure that the fitted tire does not "bite" the protruding part of the valve when rotating.
6.	Install the disc and tire assembly on the balancing machine and balance finally. Try not to use rammed (spring) weights on alloy wheels as they scratch the paint, which can lead to corrosion and paint peeling. If rammed weights are used, carefully check them for burrs and for the correct spring bend angle, as low-quality weights can cause false leaks.
6.a	"The disk is not balanced, what should I do?" Remove the tire from the rim and install the disc on the balancing machine, having previously removed the previously installed weights (cutting off the valve is optional)
6.b	Turn on the "one weight" mode on the machine, scroll the disc, put a mark on the disc in the "heaviest" place of the disc (opposite to the place where the weight is installed)
6.c	Put the tire on the rim. Locate the "valve mounting point" marker on the tire and align it with the "heavy" disc location marker
6.d	Place the disc on the balancing machine and balance the disc (after the previous operation, the machine should show the most the best way balancing)

Since the introduction of the first cars, their owners have faced the problem of wheel balancing. Previously, the speed of movement and the quality of the roads were not high, so balancing problems were of little concern. Over time, everything has changed dramatically.

Wheel imbalance is understood as the presence of unbalanced rotating masses - hubs, brake drums, etc. Due to the imbalance, it becomes much more difficult to control the machine, the service life of shock absorbers, suspension, steering wheel and traffic safety in general decreases. All this, therefore, increases the costs of those. car service.

Since a wheel is a rotating object in any car, it must have a symmetrical shape. Each point of rotation of the wheel must be equidistant from the axis of rotation. In this case, the center of gravity of the wheel should be on this very axis.

Wheel balancing refers to the process of reducing the imbalance of the wheel, hub and disc, wheel attachment and suspension elements to an acceptable level.

The reasons for imbalance are: rubber wear, deformation of the disc and other reasons that violate the shape of the wheel.

A wheel can be said to be properly balanced if its axis of rotation coincides with the main central axis of inertia. In the manufacture of wheels and rubber, certain errors from the nominal values ​​are allowed. For this reason, any wheel is not initially balanced.

There are two types of wheel imbalance - static and dynamic.

In case of static imbalance, the main axis of inertia (O1-O1) is parallel to the axis of rotation (O-O), but does not coincide with it.

Wheel imbalance can be:
- static;
- dynamic.

When static imbalance, the gravity of the unbalanced mass (mH) creates the torque. That is, a freely rotating wheel will move until the unbalanced mass takes the lowest position. In this case, the movement of the wheel will be like a pendulum.

In order to eliminate the static imbalance, it is necessary to strengthen the balancing weight (my) in the place opposite to the location of the unbalanced mass. This is called static wheel balancing.

Dynamic imbalance it is expressed in the imbalance of the wheel along its width. It is only visible when it rotates. At the same time, the axis of rotation passing along the center of gravity does not coincide with the main central axis of inertia. As a result, a certain angle α is formed between the axes.

Two masses (mH) lying in the center plane must be brought to the unbalanced masses of the wheel. When such a wheel rotates, centrifugal forces (Pц) arise, acting in opposite directions, and creating two forces with a moment of rotation M = P α. The resulting value is a characteristic of the magnitude of the dynamic imbalance.

In order to eliminate the dynamic imbalance, it is necessary to fix the balancing weights (my) on the rim edges, in the place of action of the indicated forces, on the inner side and the front of the disc. Dynamic balancing must be carried out on a special machine.

The imbalance of the wheel can be caused by the peculiarities of its design (the presence of a valve hole in the disc, tire tread pattern, etc.) or by the manufacturing technology (inaccuracies in the shape of the wheel, inhomogeneity of the material, etc.).

Radial and lateral runout, ovality and shape deviations- the main estimates of the accuracy of wheel manufacturing. The balance is influenced only by the beats, the ovality has practically no effect.

Radial Runout (RPO) is the difference in distance from various points on the tire tread to the wheel's axis of rotation. In other words, this is the deviation of the tire roundness from the ideal circle. Lateral (lateral) runout - the difference in the distance of the lateral surface, for one revolution of the wheel relative to the surface perpendicular to the axis of rotation of the wheel.

As you already know, imbalance and beatings occur due to the quality of production of unbalanced, rotating machine masses. It is almost impossible to create a perfect wheel. Therefore, in the manufacture of parts of the wheel assembly and tires, certain tolerances and norms are established. The tire is the main cause of wheel imbalance, since it is the farthest from the center of rotation, and has a large mass, complex structure and is made of materials of various compositions: rubber, fabrics and steel wires, etc. The influence on the imbalance increases with the distance from the center of the wheel of mass of the materials of the tire.

General imbalance tube tires consists of the imbalances of the tire and the ride chamber. In the chamber itself, the balance of the wheel is influenced by the difference in chamber wall thickness, joints and valves. Therefore, to improve the balance, the valve is installed on the opposite side of the joint. The tube is installed so that the valve coincides with the lightest spot on the tire. However, the amount of tube imbalance is significantly less than that of the tire.

The main reasons that affect the amount of imbalance and tire runout are:

Tread joint. Inhomogeneity of its thickness along the length of the wheel, variable tread pattern, presence of studs, for winter tires;
- joints of cord layers in the carcass and breaker;
- the joint of the sealing layer for tubeless tires;
- strong overlap of the wire in the bead ring;
- the difference in the angles of inclination of the cords in the carcass and the belt;
- divergence of the cords in the layers of the tire;
- precision of mold production;
- different thickness of the side walls;
- marking on the sidewall of the tire, which is applied to one place, etc.

Most of the named factors affecting the balance do not externally manifest themselves in any way. They refer to the internal causes of the imbalance. Reasons that can be seen with the naked eye.

An indispensable condition for improving the quality of the wheels produced is the tightening of requirements for production technology. All these measures, in the end, should lead to a reduction in imbalance and beats.

As mentioned above, it is impossible to make a perfect wheel. Therefore, the existing state standard 4754-97 sets requirements for imbalance indicators.

Correct balancing improves ride comfort. But the main thing is not even convenience. Wheel imbalance creates shock loads on the hub and bearings. And this load is not weak! An imbalance of only 20 grams. on a wheel of 14 inches, at a speed of 100 km / h, it creates a load equal to the impacts of a three kilogram sledgehammer with a frequency of 800 beats per minute.