What is Camber, Caster, King Pin Inclination, Toe in and Out?

Camber, castor, Kingpin inclination, and Toe in and out are the methods of steering geometry system.  Steering geometry is the geometric arrangement of the steering system parts and the value of the lens and angles within it.  Today in this article I will discuss what is camber, castor, Kingpin inclination, and Toe in and out.


Camber, Castor, King Pin Inclination, Toe in and Out

Camber, castor, Kingpin inclination, and Toe in and out, are the terms used in the steering system.  As the driver turns the steering wheel the movement is transmitted through the steering saved to the angular movement of the tyre.  This incline moment of tires is very important to drive the vehicle properly.  So maintaining these terms is very important to drive the vehicle and save the tires.

All these terms are discussed below –



Camber is the angle between the center line of the tire and the vertical line when viewed from the front of the wheel.  When the angle is outward so that the wheels or further effort at the top than at the bottom, the camber is positive.  When the angle is inward,  so that the wheels are closer together at the top than at the bottom,  the camber is negative.  Any amount of camber, positive or negative, tends to cause uneven or more tier wear on one side than on the other side. Camber should not exist 2 degrees.

The front wheels are not usually mounted parallel to each other but are fitted outwards slightly at the top and inward at the bottom to have a positive camber.  The purpose of the camber is to prevent the top of the wheels from tilting inward too much because of accessive loads or play in the kingpins and wheel bearings.  When the vehicle is loaded and rolling along on the road,  the load will just about bring the wheels to a verticle position.  On vehicles having negative camber, the opposite is true.


The camber on modern vehicles is adjusted using shims or an eccentric cam in the control arm shaft.  Excessive camber prevents the tire from having correct contact with the road which causes it to wear only on one side directly beneath the load.  The unequal camber causes the vehicle to roll in the direction of the will having greater camber which upsets directional stability and tends to scuff the tread on the opposite tire.

Read More – 8 Types of Steering Gearboxes and Their Functions. 



In addition to being tilted inward toward the center of the vehicle,  the kingpin axis may also be tilted forward or backward from the vertical line.  Is known as a caster.  Thus, the angle between the vertical line and the kingpin center line in the plane of the wheel is called the castor angle.  When the top of the Kingpin is backward, the caster angle is positive, and when it is forward, the castor angle is negative.  The caster angle in modern vehicles ranges from 2 2 to 8 Degrees.

The caster produces directional stability by causing the wheels to lead or follow in the same direction as the vehicle travels.  When both the front wheels are positive caster, the vehicle tends to roll out or lean out on turns.  But if the front wheels have a negative caster,  then the vehicle tends to back or lean in on turns.  There is another important effect of the caster angle.


Positive casters try to make the front wheels toe in.  With a positive Caster,  the vehicle is lowered as the wheels pivot inward.  Thus the weight of the vehicle is always trying to make the wheel toe in with the negative caster,  the wheels would try to toe out.  The positive caster increases the effort required to steer and tries to keep the wheel straight ahead.  In the heavy-duty trucks negative caster is provided.  This makes steering easier.

King Pin Inclination or Steering Axle Inclination


The angle between the vertical line and the center of the Kingpin or steering axle,  when viewed from the front of the vehicle is known as kingpin inclination or steering axle inclination.  The kingpin inclination,  in combination with the caster,  is used to provide directional stability in modern cars,  by tending to return the wheels to the street ahead position after any turn.  It also reduces steering effort particularly when the vehicle is stationary.  It also reduces tire wear.  The kingpin inclination in modern vehicles ranges from 4 to 8 Degrees.

Kingpin inclination must be equal on both sides.  If it is greater on one side than the other,  the vehicle will tend to pull to the side having the greater angle.  Also,  if the angle is too large,  the steering will become exceedingly difficult. The kingpin inclination is made adjustable only by bending.

Included angle

The combined Camber and the kingpin inclination are called the Included Angle.  This angle is important because it determines the point of intersection of the wheel and the kingpin center lines.  This, in turn, determines whether the wheel will tend to toe out or toe in.

If the point of intersection is above the ground,  the wheel tends to toe in.  If it is on the ground,  the wheel keeps its straight position without any tendency to toe in or toe out.  In this position,  the steering is called Center Point Steering.

Read More – 8 Different Ways to Increase Life of the Tire. 

Toe in and Toe Out


The front wheels are usually turned in slightly in front so that the distance between the front ends is slightly less than the distance between the back ends,  viewed from the top.  The difference between these distances is called toe-in.  On a car with two the distance between the front wheels is less at the front, than at the rear.

The amount of toe-in is usually 3 to 5 mm.  The to-in is provided to ensure parallel rolling of the front wheels, stabilize steering and preference side sleeping, and excessive tire wear.  It also serves to offset the small deflections in the wheel support system which comes out when the car is moving forward.  Although the wheels are set to toe in slightly when the car is standing still,  they tend to roll parallel on the road when the car is moving forward.  Some alignment Specialists set the front wheels in “Straight-Away Alignment” in preference to “Toe in Adjustment“.


Toe Out is the difference in angles between the two front wheels and the car frame during turns.  The steering system is designed to turn the inside wheel through a larger angle than the outside wheel when making a turn.  This condition causes the wheels to toe out on turns, due to the difference in their turning angles.

When the car is taking a turn,  the outer wheels roll on a larger radius than the inner wheel,  and the circles on which the two front wheels must rule are concentric.  Therefore the Inner wheel must take a larger angle with the car frame than that the outer wheel makes.  The toe out is secured by providing the power relationship between the steering the kill arms tie rods and the pitman’s arm.

Conclusion on Camber, Caster, King Pin Inclination, Toe in and Out

The terms I have discussed above are the terms used in steering geometric systems.  The steering system allows the driver to steer the vehicle in the right direction.  This steering system is also responsible for tire wear,  and better vehicle direction control.   Nowadays vehicles are using the power steering system which has sensors, that can detect the angles of this steering geometric system.  If you like the article then please share.

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