By How to Measure The first stage of adjusting and tuning your caster angle is to first measure and understand what your vehicle currently has. There are two main ways to measure your caster angle: Turning plates and a digital or bubble camber/caster gauge Measuring the location of the upper and
Geometry Fundamentals
What Is Suspension Geometry? Suspension geometry is the positioning and angular movement of the suspension arms and the effect that they have upon the movement of the wheel and tyre. It is caused by the different components of the suspension system all moving in their designed paths, which together generate
Suspension
What Is Suspension? Suspension in the automotive industry is a system of shocks, springs, uprights and arms that together keep a vehicle suspended above ground on its wheels. A suspension system is usually made up of the following components: Spring – This can come in many forms Damper – There
Alternative Springs
Coil springs and leaf springs are the two most common type of spring within the automotive and motorsport industries. However, other types of spring have been tried and tested in an attempt to get the edge over competitors. Some of the following springs are still used within motorsport today. Torsion
Coil Springs
What is a coil spring? A coil springs is a piece of bar that has been twisted to form the shape of a helix (spiral). It works in an up and down motion as a spring by using the vertical displacement to twist the bar making the spring. Therefore, it
Anti-Roll Bars
What is an Anti-roll bar? An anti-roll bar is a tube of metal that works as a spring between left and right wheels. An anti-roll bar connects the vertical motions of the left and right wheels and works in parallel with the coil springs. During cornering, the outside wheel (be
Dampers
What is a Damper? A damper is an oil filled tube with a piston inside. The piston moves through the oil, passing the oil through small precise holes and past a sprung shim, at a certain designed speed. Damper Construction A damper consists of: A main body A piston with
Tyre Slip Angle
What Is Slip Angle? A slip angle is the difference between the steering angle and the direction in which the tyre footprint is taking. Tyre slip angles play a major part in steering systems and have a large effect on aspects of steering geometry such as Ackermann and toe. When a
Toe
What Is Toe? Toe is the angle between each wheel with relation to the longitudinal axis of the vehicle. It is usually measured when the car is static and is measured either in degrees or in millimetres. If it is measured by distance then it is usually the difference in
Scrub Radius
What Is Scrub Radius? When viewing a wheel from front view, the scrub radius is the distance between where the extrapolated line of kingpin axis touches the road and the tyre contact patch centre point. If the extrapolated KPI is outboard of the contact patch then the scrub radius is
Instantaneous Centre
What Is An Instant Centre? The word “instant” means at that particular position of the linkage. “Centre” refers to a projected imaginary point that is effectively the pivot point of the linkage at that instant. The instant centre is a point in space, governed by the position, angle and length
Caster
What Is Caster? Caster is the measure of how far forward or behind the steering axis is to the vertical axis, viewed from the side. This is measured by drawing a line between the top and bottom pivot points of the front upright. The angle between the drawn line and
Camber Gain
What Is Camber Gain? Camber gain is the change in camber angle per amount of vertical displacement of the wheel. The most common situation is that camber will become more negative if the wheel is moved vertically upwards. Likewise, the wheel camber will become more positive if the wheel is
Camber
What Is Camber & What’s Its Purpose? Camber angle is the angle between the plane of a wheel and the vertical. It is described as positive when the top of the wheel leans outward and negative when the top of the wheel leans inward. Camber angle alters the handling characteristics
Bump Steer
What Is Bump Steer? Bump steer is a change in the steering angle of the wheel when the wheel is in bump or droop without turning of the steering wheel or lateral movement in the steering rack. This is due to the arc patterns of the wishbones and the steering
Suspension Systems
Types of Suspension Systems There are many types of suspension systems used within motorsport; the most common being a spring and damper set up. The popularity of the spring and damper set up is mostly due to its compact size and its easy, fast and direct tune-ability. There are multiple
Ackermann
Ackermann Steering Geometry In order for a car to turn smoothly, the inside wheel must travel on a smaller radii arc than the outer wheel. This is achieved by the inside wheel turning more than the outside wheel. This concept is known as Ackermann steering geometry. Perfect Ackermann geometry can