Negative and Positive Caster Symptoms & Effects


What is caster?

Caster refers to the degree of the steering wheel showing exactly how close it is to the vertical axis, either forward or backwards when observed from either side of the vehicle. A shopping cart’s front wheels give the perfect example of caster. The carts have a huge degree of positive caster, which ensure that they stick to a straight path without drifting sideways. Negative and positive caster symptoms help you to know if your car can travel down the road even when you are not handling the steering wheel tightly. Immediately you realize your car pulling on one side when driving down a straight road, it means your car has negative caster. You need to fix it using wheel realignment techniques.

Caster working principle

As soon as you turn your car’s steering wheel to either direction, its front wheels react by using the suspension system to turn on the pivots linked to it. Caster refers to the measured degrees that the steering pivot takes. Generally, positive caster occurs when the pivot’s uppermost part leans toward the vehicle’s rear. However, when it leans forward, that is a symptom of negative caster.

Negative and positive caster effects

As long as the caster does not have the right adjustment, it can bring about problems when your car is moving on a straight path. Any caster that has differences from either side will force your vehicle to lean towards the side that has negative caster. An equal caster that seems too negative can make you feel some lightness on the steering wheel, forcing the vehicle to meander aimlessly and you will not easily bring it back to move on a straight path. An equal caster that seems too positive makes the steering wheel heavy, and it can kick as soon as you hit a bump. However, caster does not influence the wear and tear on the tires of your vehicle as much.

Positive caster occurs when the axis of the steering wheel is ahead of the vertical axis. While driving on the road, this would suggest that the upper part of the coil over would move towards the vehicle’s rear. As you drive the car forward with a positive caster, it would create significant align torque, which refers to the force that straightens out the steering wheel and advances your car’s stability when moving straight. Increasing the degree of positive caster will make the steering heavier. However, today’s cars have innovative power steering configurations that prevent such problems. Generally, you will always require a significant amount of positive caster provided that your vehicle has a well fitted power steering system.

On the other hand, negative caster occurs when the steering wheel of your car is behind the vertical axis. In a general perspective, only many older vehicles experience this kind of caster symptom because of the outdated chassis dynamics, tire technology, as well as other related reasons. Vehicles of the modern-day era do not have the characteristics of negative caster. Negative caster symptoms make the steering wheel light while increasing the susceptibility of your vehicle to meander down its path without proper direction.

Finally, it is advisable to note that, irrespective of the caster settings you decide to use on your car, always ensure that you have a symmetrical degree of caster. Applying a differing degree of caster on either side of your car can make your car to pull itself towards either side of the road, especially the side having less caster.

Read also: Automatic Transmission Slipping Symptoms


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