A wheel alignment measures what angle the wheels are pointing. Importantly, wheel alignment can be used to optimize handling, stability and tyre wear by changing Toe, Caster and Camber angles.
We aim to teach you:
- What is a wheel alignment.
- Which measures get adjusted.
- Changing the alignment affects on driving.
- When do you need an alignment?
- What’s wrong when your alignment is out.
- Troubleshooting wheel alignment issue
What Is A Wheel Alignment?
A wheel alignment, also known as tracking or geometry, measures what angle the wheels are pointing.
No, I don’t mean when the steering wheel is turned. The measurement is taken when the wheel is straight to simulate driving straight.
As we live in a 3D world there are 3 angles we can measure, Toe, Camber and Caster. understanding what these are is vital to get a good chassis set up.
What Gets Adjusted And Its Effects on driving?
The best way to visualize toe angle is looking down on the vehicle from a top/birds-eye view, depending on which way the wheels are pointed defines which one of the three types of toe alignment you have.
- Parallel or Zero-Toe – If the wheels are parallel, there is zero toe angle.
- Toe-Out – If the front wheel is pointing out.
- Toe-In – if the front tips of the wheel are pointing into the centre line of the car.
The toe alignment refers to the symmetrical angle the wheel creates with the longitudinal axis of the vehicle.
Vehicle toe alignment is often used to affect corner entry turn and stability, and varies on vehicle type.
Learn more about how to use Toe alignment to enhance your vehicle performance here with our in depth look into toe geometry turning.
Looking from a head-on view of the vehicle, the angle the wheel sits in relation to its vertical axis is the camber angle.
There are three categories for camber angle.
Neutral / zero Camber, when the wheel sits directly parallel with vertical.
Positive Camber, the top of the wheel will point out away from the vehicle.
Negative Camber, this is where the bottom of the wheel points out away from the vehicle. This is one of the most important for better handling.
Increasing tyre grip during cornering is most dependent on optimising negative Camber value. This can reduce understeer and raise corner speed.
To learn more about camber and how to turn it for your setup click this, to take you to our full article on Camber Tuning.
Looking from the side view, the caster angle is the measurement of the steering pivot axis measured against the vertical axis.
It’s easiest to visualise a McPherson Strut front suspension, turn the wheel and it rotates around the steering axis. the angle this axis is tilted from the vertical is the caster angle.
The Caster angle can be used to refine steering feel, vehicle stability and optimise handling performance, and is best viewed from the side.
Learn more about how to use caster alignment to change steering feel and your vehicle performance here with our in depth look into caster geometry turning.
there are 3 measurements that make up the base of a wheel alignment, each measurement derived from the 3 dimensions.
To quickly oversimplify the 3 measurements:
- Toe alignment is the most commonly adjusted to change rotation, turn-in and stability.
- Camber is used to optimise tyre grip.
- Caster is fixed on most road-based cars so forget about it … seriously you’ll often need to acquire special compensation to adjust this to tune steering feel and stability.
When would you want a wheel Alignment?
In this section, we are going to look at when and why you might need a wheel alignment.
It might be more serious than you think.
4 common Issue Caused If The Alignment Is Out
- The steering wheel to be off centre when driving straight
“not a huge problem but annoying“
- Excessive and uneven tyre wear
“Literally flowing money away“
- The car pulls to one side when the steering wheel is being held lightly
“Far from ideal needs sorting“
- The car feels really twitchy or darting across the road.
“Serious issue, get it sorted immediately!”
These issues can easily be caused by a sudden jarring impact to the wheel such as. hitting a pothole in the road or pushing the limits of the track, on your flying lap and you cut the corner too much, smashing the apex curb… don’t ask me how I know.
Two things cause the steering wheel to be off center, unsymmetrical alignment on the right and left wheel.
Toe alignment must be symmetrical across the front axle because of steering.
If the wheel’s toe settings do not mirror each other the car will pull to one side and not steer straight.
If the toe is not symmetrical across the rear axle, example left rear 2mm toe-in, right rear 3mm toe out, it can cause the vehicle to crab. as the rear axle wants to travel in a different direction to the front. To drive straight the wheel would need to be turned slightly off to counteract the rear axle.
Also racing on a bumpy track like Oulton Park the uneven rear toe example left rear 4mm toe-out, right rear 2mm toe-out. can cause the car to feel twitchy and erratic. The rear axle skips across bumps gaining and losing grip, which isn’t the problem on its own. When you combine this effect with an uneven rear Toe it creates the issue of the rear suddenly trying to steer the front, this leaves the driver sawing at the wheel to get it drives straight.
Note: on a smooth small track with hardly any left turns like Brands Hatch Indy you could get away with this setup.
A visual indicator that your alignment is out is that the tyre is extremely warm in one area:
- Too Much Negative Camber – inside edge is excessively warm
- Too Much Positive Camber – outside edge is excessively warm
- Too Much Toe Out – then the inside edge is very warm, also running your hand across the tyre wear will have a smoother texture one way and rough texture the other. This is called feathering. Caused by the tyre being scrubbed across the ground at an angle.
- Too Much Toe In – then the outside edge is very warm, with feathering texture only on the outside edge
If you find your vehicle drifting off to one side when the steering is held lightly it can be a result of an imbalance in one area of these factors:
- Uneven toe, pointing a wheel to cause the axle to grab? across the road
- An inbalance in caster angle left to right causing the car to slightly turn one way
- Significantly uneven tyre pressure
This one is more for the track day enthusiast that drives their FWD car home. Also, can be applied on bumper tracks too.
When the car suddenly pulls one way then another when driving straight, although not all the time, creates an erratic snatchy steering feel.
The culprit is usually too much camber as the wheel hits grooves, bumps, and even tramlines left by heavy trucks in the road surface.
Longitudinal grip is reduced by increasing camber, as the wheels hit these severely uneven surfaces the grip level changes so much causing one wheel to grip more, snatching the steering one way then the other.
Unintended Wheel Alignment Change
Changing suspension components, such as fitting coilovers or changing ball joints will alter the alignment too.
Let’s have a look at the coilover example and what happens.
Coilovers are fitted for ride height adjustability, often to lower the vehicle’s ride height. By lowering the vehicle this lowers the centre of gravity improving handling, however, the vehicle suspension has moved into its bump travel. As suspension travel often follows an ark movement, which means the wheel’s camber changes. Bump steer will also occur by changing a wheel’s Toe angle with suspension travel. As the lower vehicle is sitting further into the bump, travel increases the Toe angle.
Excessive Camber – reduces lateral grip, reducing braking performance and acceleration grip. In addition to excessive tyre wear.
Excessive Toe – will reduce top speed and cause the wheels to scrub the ground. Killing the tyre’s edge as they wear quickly.
The wheel alignment is set for a specific ride height and a drastic change to the ride height can negatively affect performance. After any ride height changes, it is recommended to check the wheel Alignment to keep the wheels pointing in an optimised window.
I already know you’re smart enough to learn from other people’s mistakes, as you’re reading this. I definitely “didn’t” kill a set of good tyres by not having a wheel alignment after lowering a car, and I’m “definitely” not writing about it now so other people can learn from immature mistakes…
**Note Roll centre/bump steer correction kits are often used to correct the suspension geometry of a lowered vehicle in addition to a wheel alignment to maximise performance. Find out more about their advantages in an article coming soon.
If the coilovers act as a suspension link between the wheel hub and vehicle body, changing it can affect the wheel’s alignment.
As their mounting holes will be slightly oversized to allow the fasteners to fit through. An accumulation of the tolerances can result in the component mounting in a slightly different position, resulting in a different geometry for the suspension that needs to be corrected with a wheel alignment.
The same issue can be applied to any suspicious comment that links the vehicle body to the wheel hub. Lower control arm (aka wishbone) track rod, even ball joints.
Getting a wheel alignment will enable camber and toe settings to be corrected.
Grateful for your time to read all of this. This should have allowed you to gain an insight into how to set your car up, the effects of camber and toe, how to tune them to improve cornering performance and how to spot the issues caused by the alignment being out.
If you want to go more in depth with each individual aspect of wheel alignments, fulfil your curiosity by checking out more detailed reads on Toe, Camber and Caster alignment.