# Geometry

## How To Align Your Car

This section covers how to align your car track-side or in your garage and takes you through the procedure and the order of what to adjust.

## Caster

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

## Toe

This section covers toe on a racing car. It describes and explains how to measure, adjust and alter toe to suit the driver and the style of circuit. The section covering the different effects of toe is separated into 3 categories; front wheel drive, rear wheel drive and four wheel

## Leaf Springs

What is a Leaf Spring? Leaf springs are one of the earliest and most simple forms of spring within the automobile and motorsport world. It is simply a length of an iron or steel blade, attached to the chassis and each end and tied to the axle in the centre.

## 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

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

## King Pin Inclination

On current suspension systems, the kingpin is set at an angle to the vertical plane when viewed from the front or rear of the vehicle. This angle is known as the king pin inclination. The purpose of the KPI is to produce vertical displacement of the vehicle in during steering in an upward direction. The larger the KPI, the larger the effect. This lifting effect produces a self centering torque similar to that of caster. The KPI also generates scrub radius.

## 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

## Grip

What Is Grip? Grip, put basically, is the force generated between the tyre and the surface. The amount of grip generated and maintained is influenced heavily by the mass of the vehicle; the acceleration of the vehicle, the compound of the tyre, the compound of the road surface and by

## Front View Swing Arm

What is Front View Swing Arm (FVSA)? The front view swing arm (FVSA) instant centre location controls the roll centre height, the camber change rate and the tyre lateral scrub. The instant centre can be located inboard of the wheel or outboard of the wheel. It can be above ground

## 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

## 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