Your car is essentially a large metal and plastic box that is held in place on the road by four rotating pieces of rubber, all of which rely on a small patch of contact rubber at any one time. Plainly either your rubber has to be very sticky or you need to maximise that contact patch in order to stay on the road. Since very sticky (soft) tyres would soon wear out, and would be expensive to replace, maximising the contact patch is the usual way to ensure safe driving.
However, a vehicle moving in anything other than a straight line will be subject to many different forces, and they will be transmitted down through the tyres during cornering and other navigation changes. Added to this, roads aren't flat; in order to cope with the drainage of rainwater, roads usually have a curved top surface so that excess water runs to the curbs rather than dangerously pooling in the middle, sometimes causing dangerous aquaplaning.
So, the road isn’t flat, and your tyres have a profile too, so ensuring that you have maximum patch contact requires that the wheels are not perpendicular to the road, and this is called camber.
What is camber?
Camber can be described as the angle at which the wheel and tyre occupies relative to its position on the road. Perhaps the easiest way to envision what camber looks like is to view the wheel and tire head on. When stationary, the tyre maintains a static camber angle, whereas when the car is cornering, due to body roll, the contact patch is reduced.
In order to counteract this effect and ensure that the greatest amount of tyre on the road while cornering, camber settings must be taken into consideration and adjusted accordingly.
Manufacturers do this by designing the suspension system to hold the left- and right-hand side wheels in slightly different positions to ensure maximum rubber contact under normal driving conditions.
However, under some circumstances, sometimes drives may want to change the camber to suit their purposes, and this is then called either positive or negative camber, depending upon how the wheels are set. Let’s look at both of these cases.
- Negative Camber By applying a negative camber, the suspension system maximises the contact patch area, making the car more stable, especially under higher speeds. Many racing cars exhibit a negative camber.
- Positive Camber A positive camber makes a vehicle more stable if the ground beneath it is not smooth. The main benefit of a positive camber on any vehicle is that you don’t need to use much effort when steering them, and it is usually found on off-road vehicles.
How do I set the camber on my wheels?
Negative cambering can happen naturally by lowering your suspension; the shortening of the spring element on your car pushes the wheel centre out slightly and introduces a negative camber, however the amount of camber is difficult to control.
Many people in turn decide to adjust the camber of the car with MacPherson Strut Suspension by using an adjustable nut mechanism, while others choose an adjustable camber arm for the front and rear of a car. Both of these methods are much more precise and are available for virtually every make of car.
Advantages of camber
Plainly, cars used on the road are more likely to have a negative camber, and this can have several advantages, including:
- It improves handling
A car with a negative camber has the benefit of being more stable in a straight line compared to one with a normal camber. - Higher cornering speeds
A negative camber of just 1° can make your car more stable through corners compared to a car with standard camber. - Reduced steering wheel vibration
Negative camber has the effect of making the steering smoother as the tyre contact patch is less likely to lift off the road during cornering as can happen with normal camber.
Problems with camber
While these may be some advantages, there are also significant disadvantage, particularly when it comes to tyre maintenance. Having your tyres set at different cambers may shift the contact patch significantly, and lead to uneven and premature tyre wear.
Furthermore, while you might have more stability when cornering with a negative camber, you will certainly find that your straight-line stability will suffer, and the increased stress put on the wheel components (including the hub) can lead to sudden breakage and even wheels coming loose.
If you want to adjust the camber on your car, you should consider the implications before starting. Many people just choose to go too far with these adjustments and place unacceptable stresses on the wheels and hubs, which can be dangerous.