When we talk about the caster adjustment or caster alignment, it is important to pay attention to the camber angle, the caster angle and toe-in, and toe-out. Since it is about car craft, you may be confused to do it yourself. But in an automobile shop, they will take almost a week to solve this issue where you can solve it at a far shorter span of time in your own garage.
If you are scared to caster adjustment procedure and eager to send your car to a mechanic shop, it is completely a good idea. But what if you are in a lonesome forest or an island without any advantage like that. So I suggest you rethink about it. There are also enough occasions to force you solving this issue on your own.
The Basics of Caster Adjustment/Alignment Procedures
Though it is the high school stuff, you might find importance in late years. So let us help you out from this kind of trouble. Caster adjustment is front suspensions adjustment. So when we talk about the adjustment of caster we have to think about the adjustment of the front suspensions. The front suspension required three separate adjustments – Caster, Camber, and Toe.
Camber Angle
From this three adjustment,s the chamber is easier to contemplate. Camber visualizes when you look from the front of your car at the front tires. Now follow the tops of the tires. If they are tilted outward position, it is called positive camber. It is called zero camber if it comes straight and the negative camber describes the inward position of the tops of the tires. Camber angle has a significant impact on vehicle handling at the time of straight line driving effecting in a corner.
Why it is Caster Angle Calculation?
We should focus on Caster angle calculation because the term caster angle does not give the full picture. Caster is important for high-speed stability. High-speed ability is the effect that allows you to let go of the steering when you are driving straight. The visual of caster angle is not distinct like the camber angle. You can watch caster angle standing beside your car. The clearest example of the caster angle is the angle of the vertical axis of the tire and the steering of a bicycle. This angle is called positive caster.
If it comes straight up the tire the defining angle will be the zero casters. The negative caster is the complete opposite of the positive caster. Most of the vehicles employ positive caster. But too much of it can create camber problems as the camber and caster are directly depends on each other. The positive caster position the weight of the vehicle behind the tire that creates a torque which helps the tire push forward automatically. The same torque is required to turn the wheel.
On the other hand, the negative caster diminishes the steering effort because the vehicle weight moves forward that detracts the vehicle from high-speed stability.
Toe
Toe is the easiest to decipher. You can watch the toe closely while you look at them from the top of the suspension. When we follow them in common, it seems straighter. But the connection is a bit different. The front of tires is tilted inward to maintain the expected ratio. The toe-out means the leading edges of the front tires are angled outward.
The Tools and Utilities
Before aligning the wheel you need to extract the exact measurement. Without accuracy, your driving would have been a trap for you. So you need to measure the angles accurately. In order to do this, you need some measuring tools. You can use digital angle finders to measure the angle. Though it is accurate enough it requires some calculation. But some guys might feel this extra duty more complex.
So there are other simpler options too. The bubble gauge is another measuring tool to engage. The history of bubble gauge is as old as the automobile evolution. There are also recommendations to use a set of turn plates. But we strongly disagree with that. The round turn plates rotate on a steel fixture that allows both tires steer freely.
But turn plates have some advantages too. The turn plates help to adjust the car so easily that it feels more comfortable. But the turn plates are way more expensive than other tools. To make it affordable, bubble gauge could be the best choice.
Align Your Car
Before you start the procedure, you need to specify the ride height of your car. If you just upgrade your front suspension, you need some extra duty to adjust the ride height. Your car needs extra 50-100 miles run to establish the ride height. This run will settle the springs and the ride height.
If you have an air suspension system, it has different features to follow. It requires something equivalent to the driver weight to optimize the ride height.
Camber Setting
After settling the ride height it comes to the camber setting. Bubble gauge has a magnetic adapter that helps it to place the gauge in brake hub. Installing the adapter you will find the exact positive or negative camber angle in degrees. A traditional muscle car contains ½ degrees camber angle. If the gauge reads the angle to ½ degrees you do not need to do anything.
Otherwise, you have to change the setting. To change the setting keep 1 degree away moving the upper control arm inboard. Usually, there should be a mounting cross-shaft in the upper control arm. So if you insert the same number of shims that creates the necessary negative. The shims have to insert between the frame rail and the cross-shaft on both mounting bolts that pushes the upper control arm inboard. For more movement, there is also offset shaft available.
Caster setting
The next thing you need to fix is the caster setting. As the bubble gauge is installed, move the tire 20 degrees inward and then level the gauge. Now make the caster reading to zero using the center caster adjustment knob. Again turn the tire 20 degrees outward and you will find the positive or negative caster reading.
The ideal caster angle is positive caster up to 2 to 3 degrees max. You can add positive caster adding shims to the rear bolt. You can achieve the positive caster removing the shims from the front attachment points.
The changing of the caster angle may affect the camber. So it is recommended to check the camber angle again after the changing of a caster. Ford has used a strut rod on early Mustangs to adjust the caster easily. It was added to the lower control arm and it gained positive caster shortening the rod.
You Also check: Types of Casters: How to Choose the Right One?
Toe-in and Toe-out
The final adjustment applies to the wheel is toe-in and toe-out. That is where most of the people get stuck. If you adjust the toe without turn plates, you have to push the car roughly 10 feet forward first and then backward. It helps to measure the front tire readings more accurately. Toe setting comes after all the camber and caster setting. Because when you set the camber and caster they move the control arms. And this toe gets displaced.
But most of the cars contain right-hand threads including a threaded sleeve and locking nuts that prevent the toe from changing. Even after that entire thing, you may find sometimes the ride height of your car has changed over time. In this process, you might readjust the toe in no time. The best option is to move both left and right adjusters same amount until you get a perfect phase.
Final Thought:
Though we have given you full details to set it right, you should be careful and recheck while doing for the first time. You might prefer to examine it by a mechanic when you do it for the first time. The caster adjustment or the caster alignment is just a simple thing in the whole mechanism. But the effect is not simpler as the alignment.
FAQs
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Which caster effect is suitable for steering?
- Positive caster affects the torque more to align that improves the high-speed stability (the force that will support you to go off the steering in high speed). The negative caster makes the same thing harder and causes less responsive steering.
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Does the caster affect the pull of vehicles?
- The caster affects the pull if the Camber and Caster set in an uneven alignment. But a little tire wear can prevent the toe to affect in the same way.
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How to fix positive and negative caster?
- Positive caster is the alignment of the vertical axis of tire towards the rear of the car. Zero casters define the straighter alignment and negative caster does the exact opposite of the positive caster. And the positive caster is considered as the green line.
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How does a caster of a race car need to align?
- First of all, you need to turn the wheels 20 degrees to Right and Left while using w. vial type gauges. Then attach the gauge of the spindle and rotate it until the small vial goes show the level. Then read the camber directly from one of the two vials on either side of the gauge.
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How do you describe the Caster effect?
- There is 3 separate caster alignment that effects differently. Positive caster is the required one because the negative alignment makes the steering less responsive. But too much caster angle also makes the steering heavier. But in racing, they use excessive caster angle to gain more camber effect in racing towards a corner.
You May Be Interested: Choose The Right Caster For DIY Or Home Improvement.