Caster

Caster is the angle of a race car's steering axis when viewed from the side, measuring how much the steering components tilt forward or backward compared to perfectly vertical.

Think of caster like the angle of a shopping cart wheel. When you push a cart, its wheels naturally straighten out and follow behind - that's because shopping carts use positive caster. In racing, this same principle helps drivers control their cars more effectively.

There are three types of caster angles. Positive caster means the top of the steering axis tilts toward the back of the car, which is what most race cars use. Negative caster tilts forward, while neutral caster sits perfectly straight up and down.

Positive caster creates several important effects for race car handling. It makes the steering wheel naturally return to center after turning a corner, similar to how a motorcycle's front wheel straightens itself. This self-centering action helps drivers maintain control, especially at high speeds on straightaways.

When a car with positive caster turns into a corner, something interesting happens - the outside wheel leans inward slightly, putting more tire surface on the track. This extra grip helps the car corner faster and more safely, which is why racing teams often use much more caster than regular street cars.

However, more caster also means heavier steering. Drivers need to use more muscle to turn the wheel, especially in slow corners or when parking. Race car drivers accept this trade-off because the improved stability and cornering grip are worth the extra effort.

Racing teams adjust caster settings based on the specific track and driving conditions. Tracks with long straightaways might use more positive caster for stability, while twisty circuits might use less to make the car easier to steer through quick direction changes.

Caster works together with other suspension settings like camber and toe to create the overall handling characteristics that help drivers go fast while staying in control.