Caster is the angle created by the steering pivot point as viewed from the side of the vehicle. It can be positive or negative depending on how the upper ball joint or top strut bearing and lower ball joint are positioned in relation to each other.

A vehicle with a positive caster is more stable and caster to steer than one with a negative caster. It also will feel better at higher speeds and may be less prone to wandering or pulling to one side.

The Evolution of Casters: From Ancient Times to Modern-Day Applications

In many vehicles, caster can be adjusted using shims located between the control arm pivot shaft and the inside of the frame. This allows both caster and camber to be changed in one operation by loosening a single shim bolt.

King pin inclination (KPI) is another part of the caster geometry and is used to determine the scrub radius which is how far the steering axis is angled in relation to the center of the wheel. Larger scrub radius results in harder steering and affects handling.

Zero (0) caster is where the steering axis is perpendicular to the ground, resulting in a vehicle that tends to drift or lean heavily on one side. This type of caster is common in older vehicles and can be corrected by adding a shim between the upper strut bearing and the lower ball joint, or replacing the kingpin if it is not present.

Caster sugar, also referred to as superfine sugar, is a type of refined white sugar with particularly small granules that dissolve more easily than regular granulated sugar when liquids are added. It is commonly used in recipes for smooth mousses, puddings, custards, and delicate meringues. It is also a popular ingredient in homemade ice creams and sorbets.