When discussing suspension geometry, wheel alignment is the difference in angles between the steering axis of your car and the centerline of your wheel. Caster is an off-axis directional control point geometry angle, which helps to keep your car moving forward straight ahead. It is commonly used in racing engines and wheelchairs. Most often, front-wheel steering is done through this caster angle. You may notice this from time to time while driving when the front wheel goes straight up or straight down without performing a turn.
In general, the caster is a measure of how far the axle goes out to the ground in relation to the tire's overall height. The larger the overall height of your tires, the more caster you want. The smaller the overall height of your tires, the less caster you need. For instance, if your wheel diameter is 12 inches and your wheel size is a 4 wheel, then you will need less caster than someone with a wheel diameter of 13 inches and a 4 wheel size.
The other main component of a caster wheel is its hub material. The more material, the greater the turning radius. The more grip, the better control. The most commonly used materials are aluminum and magnesium. Aluminum provides the best overall strength and stiffness, which also allows for a larger turning radius.
There are a few different ways to install casters onto your vehicle. The most common way is to mount them on the hub side, which mounts directly underneath the wheels. Another way to install casters is to mount the entire wheel diameter, including the axle, to a rear-mounted subframe. Either way, the hub, and the entire mounting plate must remain flush with the ground to prevent vibration and reduce the risk of brake dust buildup.
The final part of a caster wheel is its assisted steering. The assisted steering system uses a rack and pinion to link the wheel to the axle. Because it requires more muscle to turn the wheels than the standard transmission, the assisted steering systems are usually only found on large trucks and race cars. However, they are very useful for small cars with poor steering control. Many models allow you to engage and disengage the assisted steering system easily, which means you can get into or out of your car with minimal effort.
One final type of wheel caster exists that is not generally used on any type of vehicle. This part, which is generally used on utility vehicles such as dump trucks or 18 wheelers, has a large drum that rolls down vertically in the utility trailer. It rolls on a track similar to a railroad track, which makes it ideal for hauling heavy equipment, construction debris, or sandbags. Its large size makes it impractical for use on passenger vehicles, but it is extremely popular on large trucks and utility trailers.
|