When you're tinkering with a repair, experimenting with wheel sizes, or tuning a newly installed suspension, an embarrassment may occur that you may have never even heard of - it's likely that the radius of the break-in shoulder will change. This "thing" can have a serious impact on the handling of your car.

Without a clear and complete understanding of all the factors that affect suspension performance, wheel alignment and geometry, it's easy to make tuning mistakes that end up making your car feel worse than before. At the same time, it is quite difficult to catch the moment when an unfortunate mistake was made.

IN general outline running shoulder radius is an elusive, almost mythical setting that sits somewhere on the edge of key adjustments such as camber, offset and wheel size. Essentially, it is determined by the location of the point in space where an imaginary line passing through the center of the suspension intersects a vertical line passing through the center of the wheel, these two lines will meet somewhere. It is important that this angle is calculated with the car without load. This is extremely important for calculations carried out by engineers.

Note the larger suspension angle relative to the wheel

In general, there are three main options for shoulder radius:

If the two lines intersect exactly at the tire contact patch, the vehicle does not have a break-in radius.

If the lines intersect below the contact patch, theoretically underground, then this is called a positive running shoulder radius.

When both lines converge above the contact patch, this is a negative run-in shoulder.

Depending on these settings, they can have a major impact on how the car handles, accelerates and stops. Different axle load designs and drive configurations require different settings, which will be calculated long before engineers begin implementing the desired handling characteristics. Yes, automakers have a ton difficult work, and this stage is just one of them. Change just one parameter in the suspension and you initiate a chain reaction that can ultimately defeat your main goal.

Running shoulder radius refers to the relative angle between the suspension and the wheel axle

At zero radius, a common belief is that this setting can make the car feel slightly unstable at the front end when cornering and under hard braking.

On the other hand, when stationary, when turning the steering wheel, you have to turn the contact patch, which is spread out as much as possible on the road surface, which requires more effort and wears out the tire more. This type of setup (zero leverage) is extremely rare on cars these days. A little more or a little less, but not zero.

You can, of course, change the zero setting. For example, "pull out" the wheels with spacers or install fully adjustable coilovers and the radius can become positive. This will cause the tire to "scrape" the ground when turning, adding uneven wear and reducing its service life. Car with positive shoulder break-in can behave unpredictably on the road: the steering wheel can be torn out of your hands when driving over uneven surfaces; when driving around corners, a “palpable moment is created that prevents uniform movement.”

The positive aspect of this setting exists for rear-wheel drive cars. They find this setting useful to help keep the front wheels in forward direction even when you let go steering wheel. Used in sports cars and comes in standard with most double wishbone suspension designs.

Volkswagen Scirocco front axle

A positive shoulder radius does not contribute to braking if for any reason there is a vehicle valid different strength. Say, if the left wheels have less traction and ABS system does not allow you to develop maximum force on them. In this case, the car will try to turn towards the wheels with more grip.

Extreme positive shoulder radius can be very severe, so much so that it was only really viable on older cars with very thin tires.

Most of us have a negative shoulder radius on our cars because it tends to go hand in hand with the MacPherson strut settings. This helps the steered front wheels feel more stable on the road, which is good for cornering and the overall handling of the car if, say, one of your front tires suddenly goes flat. Another handy "side effect" is that if you hit the water on one side of the car, the negative radius will work against the car's natural drift, mitigating the impact of going through the dangerous part.

Negative shoulder radius is safer when hydroplaning

Setting the suspension in a negative arm is the most safe option do it. It (the setting) allows you to generate certain forces that will reduce any unintentional tendency by the driver to change the direction of movement, which in the case of a positive setting may occur.

Why do we need camber, toe and caster angles?

Suspension without corners

If you do not make any angles at all, the wheel during compression and rebound will remain perpendicular to the road, in constant and reliable contact with it. True, it is structurally quite difficult to combine the central plane of rotation of the wheel and the axis of its rotation (hereinafter we are talking about the classical double wishbone suspension rear wheel drive car, for example "Lada"), since both ball joints Together with the brake mechanism, the wheels do not fit inside. And if so, then the plane and the axis “diverge” by a distance A, called the rolling shoulder (when turning, the wheel rolls around the ab axis). In motion, the rolling resistance force of the non-driving wheel creates a noticeable moment on this shoulder, which changes abruptly when driving over uneven surfaces. As a result, the steering wheel will constantly be torn from your hands.

In the transverse plane, the position of the wheel is characterized by angles α (camber) and β (tilt of the steering axis)

In addition, you will have to use muscular strength to overcome this most significant moment in a turn. Therefore, positive (in in this case) it is desirable to reduce the rolling shoulder, or even reduce it to zero. To do this, you can tilt the rotation axis ab. It is important here not to overdo it, so that when moving up, the wheel does not fall too much inward.

The rolling of an inclined wheel resembles the rolling of a cone

In practice, they do this: by slightly tilting the rotation axis (β), the desired value is obtained by tilting the plane of rotation of the wheel (α). The wasp angle is the camber. At this angle the wheel rests on the road. The tire in the contact area is deformed.

It turns out that the car is moving as if on two cones, tending to roll to the sides. To compensate for this trouble, the planes of rotation of the wheels must be brought together. The process is called toe adjustment. Both parameters are tightly coupled. That is, if the camber angle is zero, there should be no toe-in; negative - divergence is required, otherwise the tires will “burn.” If the car has a different wheel camber, it will be pulled towards the wheel with a greater inclination.

With a positive rolling shoulder, turning the wheel is accompanied by lifting the front of the body

The other two angles ensure stabilization of the steered wheels - in other words, they force the car to drive straight with the steering wheel released. The lateral inclination angle of the steering axis (β) is responsible for weight stabilization. It is easy to notice that with this scheme (fig.) at the moment the wheel deviates from the “neutral”, the front begins to rise. And since it weighs a lot, when you release the steering wheel under the influence of gravity, the system tends to take initial position, corresponding to motion in a straight line. True, for this it is necessary to maintain that same, albeit small, but undesirable positive rolling shoulder.

Caster - angle longitudinal inclination rotation axis

The longitudinal angle of inclination of the steering axis - caster - provides dynamic stabilization. Its principle is clear from the behavior of the piano wheel - when moving, it tends to be behind the leg, that is, to take the most stable position. To achieve the same effect in a car, the point where the steering axis intersects the road surface (c) must be in front of the center of the wheel contact patch (d). To do this, the axis of rotation is tilted along...

This is how a caster “works”

Now, when turning, the lateral reactions of the road behind... (thanks to the caster!) try to return the wheel to its place.
Moreover, if the car is subject to a lateral force that is not associated with turning (for example, you are driving on a slope or in a crosswind), then the caster provides smooth turn the machine “downhill” or “downwind” and prevents it from tipping over.

Positive (a) and negative (b) rolling shoulders

IN front wheel drive car with the MacPherson suspension the situation is completely different. This design makes it possible to obtain a zero and even negative (Fig. b) rolling shoulder - after all, only the support of a single lever needs to be “stuffed” inside the wheel. The camber angle (and, accordingly, toe angle) can be easily minimized. That’s right: VAZs of the “eighth” family have camber - 0°±30", toe - 0±1 mm. Since the front wheels are now pulling the car, dynamic stabilization during acceleration it is not required - the wheel no longer rolls behind the leg, but pulls it along with it. A small (1°30") angle of longitudinal inclination of the steering axis is preserved for stability during braking. A significant contribution to the “correct” behavior of the car is made by the negative rolling arm - as the rolling resistance of the wheel increases, it automatically corrects the trajectory.

The angles for each car model are determined after many tests, refinements and re-tests. On an old, worn-out car, elastic deformations of the suspension (primarily rubber elements) much more than the new one - the wheels diverge noticeably from much less force. But as soon as you stop, in static conditions all the corners are back in their place. So adjusting a loose suspension is a waste of time. First you need to repair it.
There are other ways to nullify all the efforts of developers. For example, give a good fuck back car. Lo and behold, the caster changed sign and the memories from the dynamic stabilization remained. And if during acceleration the “athlete” can still cope with the situation, then during emergency braking it is unlikely. And if you add non-standard tires and wheels with a different offset, it is simply impossible to predict what will happen in the end.

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The simplest and seemingly obvious solution is to not make any corners at all. In this case, the wheel during compression and rebound remains perpendicular to the road, in constant and reliable contact with it (Fig. 1). True, it is structurally quite difficult to combine the central plane of rotation of the wheel and the axis of its rotation (hereinafter we are talking about the classic double-wishbone suspension of rear-wheel drive Lada cars), since both ball joints, together with the brake mechanism, do not fit inside the wheel. And if so, then the plane and the axis “diverge” by a distance A, called the rolling shoulder (when turning, the wheel rolls around the ab axis). In motion, the rolling resistance force of the non-driving wheel creates a noticeable moment on this shoulder, which changes abruptly when driving over uneven surfaces. Few people will enjoy driving with a steering wheel constantly tearing out of their hands!

In addition, you will have to work hard to overcome this very moment in the turn. Therefore, it is desirable to reduce the positive (in this case) rolling leverage, or even reduce it to zero. To do this, you can tilt the rotation axis ab (Fig. 2). It is important here not to overdo it, so that when moving up, the wheel does not fall too much inward. In practice, they do this: slightly tilting the rotation axis (b), the desired value is obtained by tilting the plane of rotation of the wheel (a). Angle a is the camber. At this angle the wheel rests on the road. The tire in the contact zone is deformed (Fig. 3).

It turns out that the car is moving as if on two cones, tending to roll to the sides. To compensate for this trouble, the planes of rotation of the wheels must be brought together. The process is called toe adjustment. As you may have guessed, both parameters are tightly connected. That is, if the camber angle is zero, there should be no toe-in; negative - divergence is required, otherwise the tires will “burn.” If the car has a different wheel camber, it will be pulled towards the wheel with a greater inclination.

The other two angles ensure stabilization of the steered wheels - in other words, they force the car to drive straight with the steering wheel released. The first, already familiar to us, angle of transverse inclination of the turning axis (b) is responsible for weight stabilization. It is easy to notice that with this scheme (Fig. 4), at the moment the wheel deviates from the “neutral”, the front begins to rise. And since it weighs a lot, when the steering wheel is released under the influence of gravity, the system tends to take its initial position, corresponding to movement in a straight line. True, for this it is necessary to maintain that same, albeit small, but undesirable positive rolling shoulder.

The longitudinal angle of inclination of the turning axis - caster - provides dynamic stabilization (Fig. 5). Its principle is clear from the behavior of the piano wheel - when moving, it tends to be behind the leg, that is, to take the most stable position. To achieve the same effect in a car, the point where the steering axis intersects the road surface (c) must be in front of the center of the wheel contact patch (d). To do this, the axis of rotation is tilted along. Now, when turning, the lateral reactions of the road applied behind... (thanks to the caster!) (Fig. 6) try to return the wheel to its place.

Moreover, if the car is subject to a lateral force that is not associated with turning (for example, you are driving along a slope or in a crosswind), then the caster ensures that the car turns smoothly “downhill” or “downwind” when the steering wheel is accidentally released and does not allow it to capsize.

In a front-wheel drive car with MacPherson suspension, the situation is completely different. This design makes it possible to obtain a zero and even negative (Fig. 7b) rolling shoulder - after all, only the support of a single lever needs to be “stuffed” inside the wheel. The camber angle (and, accordingly, toe angle) can be easily minimized. That’s right: the VAZs of the “eighth” family that are familiar to everyone have a camber of 0°±30", a toe-in of 0±1 mm. Since the front wheels are now pulling the car, dynamic stabilization during acceleration is not required - the wheel no longer rolls behind the leg, but pulls it along. A small (1°30") caster angle is maintained for stability when braking. A significant contribution to the “correct” behavior of the car is made by the negative rolling shoulder - as the rolling resistance of the wheel increases, it automatically corrects the trajectory.

As you can see, it is difficult to overestimate the impact of suspension geometry on handling and stability. Naturally, the designers pay close attention to it. The angles for each car model are determined after a great many tests, development work and more tests! But only... based on a working car. On an old, worn-out car, the elastic deformations of the suspension (primarily the rubber elements) are much greater than on a new one - the wheels diverge noticeably from much smaller forces. But as soon as you stop, in static conditions all the corners are back in their place. So adjusting a loose suspension is a monkey's work! First you need to repair it.

There are other ways to nullify all the efforts of developers. For example, lift up the back of the car well. Lo and behold, the caster changed sign and the memories from the dynamic stabilization remained. And if during acceleration the “athlete” can still cope with the situation, then during emergency braking it is unlikely. And if you add non-standard tires and wheels with a different offset, who can predict what will happen in the end? Ahead of schedule worn tires and “dead” bearings are not so bad. It could be worse...

Rice. 1. “Pendant without corners.”

Rice. 2. In the transverse plane, the position of the wheel is characterized by angles a (camber) and b (inclination of the steering axis).

Rice. 3. The rolling of an inclined wheel resembles the rolling of a cone.

Rice. 4. With a positive rolling shoulder, turning the wheel is accompanied by lifting the front of the body.

Rice. 5. Caster - the angle of longitudinal inclination of the turning axis.

Rice. 6. This is how the caster “works”.

Rice. 7. Positive (a) and negative (b) rolling shoulders.

Explanations

Rolling shoulder

The break-in shoulder is the distance between the center of the contact patch of the wheel with the road (the center of the tire imprint) and the point of intersection of the steering axis of the steered wheel (pivot axle) with the road surface.

F 1 = Braking force or rolling resistance force

F 2 = Traction force

r s = Running shoulder

Reducing the running-in shoulder (picture 1 b ) reduces the force on the steering wheel rim. The small break-in shoulder reduces the response to impacts of the steered wheel on road unevenness.

When braking with a brake mechanism located on the wheel, a longitudinal force occursF 1 , which forms the momentF 1 * r S . This moment leads to the appearance of force on the steering rod and with a positive size of the running armr S presses the wheel in the direction corresponding to negative toe.

On a vehicle equipped with ABS?

At ABS operation longitudinal forces of different magnitudes arise applied to the right and left wheels, which are transmitted in the form of shocks to the steering wheel. In this case, the running shoulder should be equal to zero, but it is better if the running shoulder has a negative value.

The suspension of wheels of any type can be considered as a cantilever wheel mounted relative to the car body, therefore, when braking, a longitudinal force arises that tends to turn this wheel, and the wheel will always tend to turn its front part outward, that is, towards negative toe. Installing a negative running arm will allow you to obtain a moment of longitudinal force, which will be in the direction the opposite side moment tending to turn the wheel towards negative toe. Most vehicles not equipped with FBS have circuits braking systems have a diagonal connection pattern, the running shoulder is usually a negative value. Any incorrect modification made to the design of the vehicle, such as installing rims with an increased offset, which occurs when you want to install wide tires, or installing a spacer between the hub and the wheel rim, is unacceptable. Changing the run-in shoulder can have a negative impact on straight-line stability, especially when braking, and loss of control when cornering.

The break-in shoulder is one of the most important parameters front suspension.

With shoulder break-in r s related:

• spring displacement on the McPherson strut;
• wheel rim offset ET (distance from the plane of symmetry of the tire to the plane of the wheel rim in contact with the hub);
• force on the steering wheel both statically and dynamically;
• vehicle stability when braking;
• the position of the bearing assembly in the hub, and with it the position of the wheel: the longitudinal plane of symmetry of the tire should be located at the base of the bearing(s), preferably in the center (Fig. 2). Otherwise, the declared life of the bearing(s) will not be achieved.

Rice. 2. Relative position of the plane of symmetry of the tire and the base of the bearing(s): a – conical roller; b – double-row ball

Wheel rim offset ET is a parameter that drivers pay attention to only when, having installed more wide wheel, it begins to touch the arch. And then the decision comes on its own: take discs with lower ET. “Good people” say: “a deviation of ±5 mm is acceptable.” What if the factory already used these 5 mm, what then?! And then there is a loss of control during emergency braking in mixed mode (unequal grip on the left and right).

A striking example illustrating the importance of the break-in shoulder is given in the Automotive Industry magazine:

Test No. 1. Wheels with such ET were installed on the car that they received a break-in shoulder r s =+5 mm. Acceleration up to 60 km/h. They release the steering wheel (!!!) and use emergency braking on mixed doubles. The result is a 720° turn of the car - as expected.

Test No. 2. Everything is the same, but r s =–5 mm (discs with ET 10 mm more than the first, by the way, this reduced the track by 20 mm). The result is the car pulls 15° - unexpectedly?!

And this is the answer to those who believe that the wider the track, the more stable the car, and wheel rims only affect the exterior of the car.

The reason for such different behavior of the car after a seemingly cosmetic change is the elastokinematics of the steering linkage (Fig. 3).

Rice. 3. The influence of positive (a) and negative (b) run-in shoulder r s = R 1 /cos σ (see Fig. 4) on vehicle stability during braking:

R`x 1 >R“x 1 , R`x 2 =R“x 2 – braking forces on the corresponding wheels;

F and – inertia force applied to the center of mass of the car

Rice. 4. Parameters for installing steered wheels

If the braking force is greater, for example, on the left, then a turning moment equal to the difference acts on the center of mass of the car braking forces multiplied by the shoulder (half the gauge). But since the forces on the left and right are unbalanced, a moment acts on the steering linkage

(R`*x 1 –R“*x 1)·R 1 .

Steering linkage rotates (due to deformation of supports, levers, body). In the case of a positive running-in arm, this rotation increases the turning moment; in the case of a negative arm, it partially or completely compensates for it.

Negative run-in leverage is not easy to obtain. They increase the ET of the disks (depth), the transverse angle of inclination of the pivot axle and the camber angle of the wheels. But with an increase in the first angle, the force on the steering wheel increases, and with an increase in camber, the grip of the tires with the road when turning worsens (negative camber is needed!). The wider the tire profile, the more difficult it is to structurally place it in the wheel. brake mechanisms, hub, ball joints, tie rods and drive.

An excellent solution to the problem of reducing the running shoulder is the use of a multi-link front suspension with four ball joints (see Fig. 5).

Rice. 5: Multi-link suspension front steered wheel manufacturer VAG

The design is very similar to the classic triangular double wishbone suspension. However, instead of one ball joint, two are used at the vertex of the triangle - a quadrilateral is formed. This design is inoperative without the fifth lever - the steering rod. On triangular levers, the steering axis of the wheel passed through the centers of the ball joints. IN new design this axis is virtual and extends far beyond the boundaries of the quadrilateral (Fig. 6).

Rice. 56 Diagram of wheel rotation on a multi-link front suspension (the second pair of levers is not shown)

Based on materials Study guide « Performance properties cars", A. Sh. Khusainov

Mikhail's note revealed some questions regarding the adjustment of the steering wheel angles.

Together we will try to figure it out.

Camber(camber)-- reflects the orientation of the wheel relative to the vertical and is defined as the angle between the vertical and the plane of rotation of the wheel.

F1 cars have negative camber

Convergence(TOE) --characterizes the orientation of the wheels relative to the longitudinal axis of the vehicle.

It is believed that the influence of negative camber needs to be compensated by negative toe-in and vice versa, due to the deformation of the tire in the contact patch, the “cambered” wheel can be represented as the base of a cone.

The picture shows positive camber and positive toe.

One of the positive aspects of negative toe-in is increased steering response.

In addition to camber and toe, which can be seen with the eye, there are several other parameters that affect the car’s handling.

Rolling shoulder- one of the parameters that affects the sensitivity of the steering. Thanks to it, the steering wheel “signals” a violation of the equality of longitudinal reactions on the steered wheels (uneven surfaces, uneven distribution of braking forces between the right and left wheels).

Positive (a) and negative (6) rolling arm:
A, B - centers of ball joints of the front suspension;
B is the point of intersection of the conventional axis, the “pivot,” with the road surface;
G - the middle of the tire contact patch with the road.

The rolling shoulder does not affect the ease of steering. In the presence of a rolling shoulder, the longitudinal forces acting on the steered wheels create moments that tend to turn them around the turning axis. But in the case of equal forces on both wheels, the moments turn out to be “mirror”, i.e. equal and opposite directions. Mutually compensating for each other, they do not affect the steering wheel. However, the moments load the parts of the steering linkage with tensile or compressive (depending on the location of the rolling arm) forces.

(Negative camber increases the positive value of the rolling arm)

Weight stabilization of the front wheels.

When the wheel turns, the front part of the car rises, so under the influence of weight the wheel tends to take a position of linear movement. Weight, or static, stabilization of the front wheels (i.e., ensuring their return to the direction of straight-line motion) is ensured by a positive rolling arm and the lateral inclination angle of the steering column axis.

Lateral slope swivel stand.

SAI - angle of lateral inclination of the steering axis (as the lateral angle decreases, the effectiveness of weight stabilization decreases; excessive tilt leads to excessive force on the steering wheel)

IA - included angle (an unchanged design parameter of the car, determines the mutual orientation of the steering axis and the wheel axle)

γ - wheel camber angle

r - rolling shoulder (in this case, positive)

rts - lateral displacement of the axis of rotation

In a 2-link suspension, the included angle is determined only by the axle geometry.

The mechanism of weight stabilization.

When the wheel turns, its axle moves along an arc of a circle, the plane of which is perpendicular to the axis of rotation. If the axis is vertical, the trunnion moves horizontally. If the axis is tilted, the path of the trunnion deviates from the horizontal.

The arc that the axle describes has a peak and descending sections. Position top point The arc is determined by the direction of inclination of the wheel's turning axis. With lateral tilt, the top of the arc corresponds to the neutral position of the wheel. This means that when the wheel deviates from neutral in any direction, the axle (and with it the wheel) will tend to fall below the initial level. The wheel works like a jack - it lifts the part of the car located above it. The “jack” is counteracted by a force that directly depends on a number of parameters: the weight of the lifted part of the car, the angle of inclination of the axle, the magnitude of its lateral displacement and the angle of rotation of the wheel. She tries to return everything to its original, stable position, i.e. turn the steering wheel to neutral position

Dynamic stabilization of the front wheels.

To ensure stability of motion, i.e., the desire of the car to move straight, only the transverse inclination of the axis of the steering wheel strut is not enough, especially on high speed. This is due to the appearance of additional rolling resistance and the gyroscopic effect, which can cause the influence of the wheel under the action of a disturbing force. For greater stability, a longitudinal tilt of the steering axis of the wheel is introduced, due to which the point of intersection of the steering axis with the road surface is shifted forward relative to the contact of the tire with the road. Now the wheel tends to take a position behind the point of intersection of the wheel axis with the road, and the greater the rolling resistance force, the greater the moment that returns the wheel to the position of straight-line motion. With such a displacement, the force acting on the wheel when turning also tends to straighten the wheel.

The main function of the caster is high-speed (or dynamic) stabilization of the steering wheels of the car. Stabilization in this case is the ability of the steered wheels to resist deviation from the neutral (corresponding to linear motion) position and automatically return to it after the cessation of the external forces that caused the deviation.

Deflection of the steered wheels can be caused by deliberate actions associated with changing the direction of movement. In this case, the stabilizing effect assists when exiting a corner, automatically returning the wheels to neutral. But at the entrance to the turn and at its apex, the “driver,” on the contrary, has to overcome the “resistance” of the wheels, applying a certain force to the steering wheel. The reactive force generated on the steering wheel creates what is called steering feedback.

The required reach of the turning axis (it is called the stabilization arm) is most often obtained by tilting it in the longitudinal direction at an angle, which is called caster. At low caster values, the stabilization arm turns out to be small in relation to the size of the wheel, and the longitudinal force arm (rolling resistance or traction) is completely negligible. Therefore, they are not able to stabilize a massive wheel. "Rubber comes to the rescue." At the moment of action of destabilizing lateral forces in the contact patch car wheel quite powerful transverse (lateral) reactions are generated with the road, countering the disturbance. They arise due to complex processes deformation of a tire rolling with lateral slip.

Additional information about side pull, the mechanism of side reaction formation and stabilizing moment is given below.

As a result of the wheel pulling away under the influence of a lateral force (force pulling), the resultant of the elementary lateral reactions always turns out to be shifted back in the direction of travel from the center of the contact area. That is, the stabilizing moment acts on the wheel even when the trace of the turning axis coincides with the center of the contact patch. The question arises: why do you need a caster at all? The fact is that the stabilizing moment (Mst) depends on various factors (tire design and pressure in it, wheel load, road grip, magnitude of longitudinal forces, etc.) and is not always sufficient for optimal stabilization of the steered wheels. In this case, the stabilization arm is increased by the longitudinal tilt of the rotation axis, i.e. positive caster. Destabilizing forces acting on the wheel of a moving car are caused by different reasons, but, as a rule, they have the same, inertial character. Accordingly, both lateral reactions and stabilizing moments increase with increasing speed. Therefore, the stabilization of the steered wheels, to which caster makes a significant contribution, is called high-speed. With increasing speed, it “steers” the behavior of the steered wheels. At low speeds, the influence of this mechanism becomes insignificant; weight stabilization works here, which is responsible for the tilt of the wheel turning axis in the transverse direction.

Setting the steering axis with positive caster is useful not only for stabilizing them. Positive caster eliminates the danger of sudden changes in trajectory.

Another favorable consequence of the longitudinal inclination of the steering axis leads to a significant change in the camber of the steered wheels when turning them.

It is easier to understand the mechanism of dependence if we imagine a hypothetical situation where the wheel's rotation axis is horizontal (caster is 90°). In this case, the “turn” of the steered wheel is completely transformed into a change in its inclination relative to the road surface, i.e. collapse The tendency is that the camber of the outside wheel becomes more negative during a turn, and the camber of the inside wheel becomes more positive. The larger the caster, the more change camber angles in turns.

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Below is a printout of the settings of the F1 car, Lotus E20

Sources.