Fungsi Caster Mobil Pada Wheel Alignment Roda Depan

Caster is a factor in wheel alignment designed to synchronize with other geometric angles, such as camber and toe, to ensure a safe and comfortable ride. Caster angle is the angle formed by the tilt of the steering axis (kingpin) relative to the vertical wheel centerline when viewed from the side of the vehicle. The caster angle functions to steer the wheels, ensuring they remain stable in a straight line even when the steering wheel is released. Furthermore, caster angle maintains wheel stability during turns, preventing skidding. When a vehicle turns, the wheel's caster angle changes, shifting to a negative direction, ensuring proper tire support on the road surface. On some vehicles, the caster angle cannot be adjusted. If the caster is outside the factory standard, it must be repaired or replaced. Theoretically, there are three types of caster angles: positive caster angle, negative caster angle, and zero caster angle. A positive caster angle is the angle obtained when the kingpin is tilted rearward or behind the vertical axis of the wheel. Almost all modern vehicles use a positive caster angle. Properly designing a positive caster angle according to factory specifications will improve wheel stability when the car is traveling straight. Another advantage is that the steering wheel will easily return to a straight position after turning. However, if the caster angle is too positive, the car will vibrate strongly when traveling over uneven roads. This vibration will be very noticeable in the steering wheel. A positive caster angle will also make steering heavier, but this effect can be eliminated with power steering. A negative caster angle is the opposite of a positive caster angle. It is the angle obtained when the kingpin axis is tilted forward or in front of the vertical axis of the wheel. Many vintage cars used a negative caster angle. The goal was to achieve a lighter steering force, as power steering technology was not yet available in the past. A negative caster angle will make steering feel lighter, but it will also make the vehicle difficult to control, especially when turning. A negative caster angle will cause severe wheel vibration and shock. Furthermore, the wheels will be unstable when traveling straight. A zero caster angle occurs when the kingpin axis is aligned with the vertical axis of the wheel. A zero caster angle provides no benefit. Because the kingpin angle tends to lean forward when the car is moving, the effect is similar to a negative caster angle, although not as severe as a negative caster angle. The most common caster angle used in vehicles is a positive caster angle. The caster angle specification is generally between 3° and 8°, and the permissible difference between the right and left wheels must not exceed 0.5 degrees, or 30' (30 minutes). If a car has unbalanced caster, it will pull to the side with the less positive caster.