Category: Geometry Explained

Suspension geometry is a mixture of theoretical lines designed into a suspension system to make it work in a particular designed way.

There are more aspects to suspension geometry but the most influential are listed below and are the focus of this website.

  • Anti Squat, Dive and Lift Geometry

    Anti-squat, anti-dive and anti-lift geometry which will be referred to as “anti-geometry” when discussing them as a whole is a form of geometry at the front and rear wheels that alters and controls the amount that a car will compress the springs due to acceleration, …

  • Wheel Rate and Chassis Roll Stiffness

    Wheel Rate Wheel rate is effectively the spring rate when measured at the wheel as opposed to at the spring. It is important to understand the wheel rate of a vehicle for calculating the spring rates and understanding the car dynamically. Coil Spring Wheel Rate …

  • 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 …

  • 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 …

  • King Pin Inclination

    What Is King Pin Inclination (KPI)? 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 …

  • Instant 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 …

  • 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. …

  • 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 …

  • 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 …

  • 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 …

  • 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 …

  • 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 allowing the car to turn. This is achieved by the inside wheel turning more than the outside wheel. This concept …