What is Caster? (Positive & Negative Caster Effects)
What is caster? Caster refers to the angle of the steering axis of a wheel relative to a vertical line. A wheel steers on a vehicle such as a bicycle, car, or motorcycle.
The angle is measured by the angular distance between the vertical and the line of rotation (a line running from the lower ball joint to the upper ball joint). Many racers like to change the caster angle to improve the vehicle’s performance under certain driving conditions.
The wake effect doesn’t just happen on cars; it happens on anything that has wheels on the bottom. For example, look at the wheels on a shopping cart at the supermarket.
Positive lug effect
Positive caster effect With positive caster, the steering axis is tilted forward of the vertical axis and towards the rear of the vehicle. This means that the coil spring or coil springs on the shock absorbers point backwards when driving. The forward-facing caster driving effect is noticeable when driving forward.
The huge torque straightens the steering wheel when driving in a straight line, making the vehicle more stable. Too much positive caster angle will make the steering heavy.
Fortunately, most modern vehicles have power steering, and a positive caster angle will reduce the weight of the steering wheel. So make sure the vehicle you want to buy has good power steering; it’s almost a given these days.
Negative Caster Effect
With a negative caster angle, the steering axis is tilted behind the vertical axis, towards the front of the vehicle. Many older cars have negative caster angles on their wheels. The main reason for using negative caster can be attributed to the classic tire and chassis technology of the time. Additionally, power steering didn’t exist back then, so car manufacturers had to find a way to make the steering wheel lighter for the driver. Negative lug was the only way to achieve this.
If you look at the way cars are built these days, their internal structures and chassis aren’t equipped to handle negative caster. Why should they? Power steering has revolutionized the automotive industry, providing drivers with a much safer and more stable driving experience.
In addition, negative caster has issues with maintaining stability and staying straight, as the steering is often too light and slightly jerky. However, some drivers still choose to have negative caster on their vehicles because they prefer it.
Important Tips
If you change the caster settings on your vehicle, make sure the caster angles are perfectly symmetrical.
If you miscalculate the caster angle for the different wheels on your car, you will find that your car pulls more to one side than the other. The side with the smallest caster angle is the side the car will pull on. If you are not confident, ask a professional to change the caster angle for you.