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On this section of our website, Our Challenger Tyres & Exhausts Team in Hoyland has put some background information about wheel alignment/tracking and explain a few specialist terms. Probably you (like most vehicle owners) do not even think about things like wheel alignment and consider it a waste of time and money. After reading this page, you will surely change your mind…
We start with the explanation of the terms.
Then we will explain their effect on the road behaviour of the car.
Probably you have already heard this term before.
Camber is the wheel angle, in relation to the road surface,
viewed from the front side of the car
Just think of a line in the centre of the tyre tread. ("middle-line")
At 0º this line will be perpendicular to the road. (black line)
If these "middle lines" form a "V", then we speak of "Positive Camber” (see red lines).
We speak of a "negative camber" once these lines form an "A" (see green lines)
Here we view the vehicle from the sides
Now imagine a line in which passes through the axis of the steering.
That is the axis that the front wheels will turn around during steering.
Usually, it runs through the upper- and lower- ball joints, or the centre-line of the McPherson Strut.
The green line shows the "positive caster, so if this line’s top is tilting to the back of the vehicle.
The red line shows the "negative caster".
The positive caster shows a "self-centring effect" which ensures straight-ahead stability.
Just like the front wheels of a shopping cart.
“TOE-IN” and “TOE-OUT”
Now we view the vehicle from above;
Imagine lines in the direction of travel, which run through the centre of the tread. (wheel position)
The red lines show "Toe-track", then the lines for the wheels cross; "A-shape"
The green lines show "Off-track"; then the lines are crossing after the wheels; "V-shape."
We hope that you are now able to understand the picture below:
The so-called camber is usually around -½ to -5½ Degrees. (-)
While taking a turn, the vehicle’s body will begin to roll/tilt.
This ensures more positive camber on the wheels.
A “negative camber” will be compensating for this effect, resulting in increased grip and stabilisation during turning.
Note, a “negative camber” means to build up of forces on the vehicle’s wheels that we call "camber-thrust".
This will push the wheels towards the middle of the car.
If the car goes straight, the camber-thrust forces of the left and right wheel will cancel each other out. This ensures better "straight-ahead stability."
For example, in a left turn, the left wheel will want to "lift" from a tiny bit to completely at times. Then the camber-the rest of the right wheel ensures that the curve is taken even sharper; Then "over-send."
That is why engineers try to ensure that there is always a - ½ ° (-) Camber left over when taking a turn, in fully engaged condition.
Then the camber-thrust works best.
So from the height of the ride more and more negative camber will arise during compression.
Simultaneously, the body-roll will bend this extra camber in turns, and hopefully, the desired ½ degree will remain for the grip and also the desired pre-heating of the tyres.
The tyres will also wear more quietly and more evenly.
Is a “negative camber” an entirely good phenomenon?
Because it causes increased tyre wear, particularly on the insides of the tyres while driving straight.
Would it be ideal if the tyres would always be right-angled towards the road surface all the time?
This would be more of an issue for a passenger car compared to a racing car. This is because it has more spring travel, the suspension is much softer and increased “body-roll”.
We also want the tyres to last as long as possible, a racer only needs to get to the finish flag as fast as possible and is already happy. The tyres will be changed after the race.
So we will have to search for a compromise;
This usually results in -½ to -2 degrees camber (negative).
On most regular cars, adjusting the camber is quite difficult.
Also, the "adjustment range" is often no more than + ½ and -½ grade.
Will usually be in the range of +2 to +5½ degrees, positive (+).
Caster is only applicable to the front wheels, also called the “steering-wheels”.
It is, among other things, required for the straightline- stability or one might say; "self-steering effect."
To make you understand a bit better what the caster does, let’s take a shopping trolley as an example. The trolley’s wheels are equipped with + (positive) caster angle, and so it will roll the way in which the trolley is pushed.
Would turn its wheels by 180 °, then they would get a negative caster.
The trolley is now a lot harder to push (could even block) and is now suddenly unpredictable and not stable.
A “positive caster” has also directly affected the camber during steering;
The outer wheel is getting more of a “negative camber” while the inner wheel gets a less negative camber.
A rather “positive caster” provides increased "response" while driving, especially without power steering.
You might think now it might be better to have more of a “positive caster. That is not the case, however.
It would only make the steering heavier as caster increases.
There is another disadvantage;
During the filing of a bend, positive caster creates the following undesirable side effect;
The inside wheel will rise while the outside wheel will lower.
This ensures that more weight will rest on the outer wheel, resulting in a "rather loose" sensation in the vehicle.
The outer front tyre now wears extra hard, and it already has a heavy load due to the extra load due to the body roll, camber-thrust and camber strain on the inside of the tyre,
Influences three important driving characteristics;
1; Tyre wear 2; Straight-ahead stability 3; Bend-send-in moment
For a minimal tyre wear it would be perfect if the tyres/wheels were parallel while driving - no toe-in and no toe-out, so 0 °.
In the case of a front wheel drive, it is achieved by having a little toe-out in a static condition. A rear wheel drive should then have a little toe-in.
There is a difference between "Static and Dynamic Tracking";
Especially with a front wheel drive we can see this, but also with a rear wheel drive with independent wheel suspension this is the order; What....?
Well that when the drive forces are released, the moment of the drive shafts ensures that the wheel suspension suffers a high load in all its pivot points as well as on its connecting components.
This ensures that this suspension construction will deform.
The driven wheels want to go forward and will "spin."
The above applies, especially to street cars. By using flexible rubbers for comfort and noise reduction, there is much more movement in these types of suspensions.
That is why we often start out with static.
High spouting values will cause the inner edges of the tyres to "eat", which causes extra wear.
A lot of toe-in will mainly burden the outside of the tires.
Outreach will mainly improve the steering response.
Toe-line will above all increase straightforwardness.
Sometimes toe-on or off-track is also used for a different effect; "Tyre temperature".
For race tyres, it is very important that they achieve the right operating temperature to ensure maximum grip and performance.
If tyres remain too cold, the scrub effect of the track may be too high to offer a solution.
The scrub effect also provides a cleansing effect on the tread surface, which means that the brakes can be braked and there will also be more grip in the corners.
Regular cars are usually equipped with toe-in steering behaviour is then sacrificed for straight-ahead driving stability.
In racing cars, the steering behaviour is usually more important than the straight-line stability, so toe-out is usually preferred.
In the case of independent wheel suspension at the rear wheels, toe-on and off-track also apply here.
Roughly speaking, the effects are the same as with the front wheels.
The bottom line:
All facts mentioned are of major importance in regards to safe road holding and other things such as tyre wear and of course the comfort of the driver of the vehicle.
Our advice is, therefore; use the standard settings of the vehicle manufacturers or the values that have been tested and confirmed to be ideal, for a start for a good track adjustment of your car’s chassis.
When replacing springs, complete dampers and/or camber plates, it is absolutely necessary to adjust the track again.
Do not save on professional wheel alignment with advanced equipment.
This could completely negate your investment in improving your chassis.
The driving characteristics could deteriorate in such a way that you don’t even feel the improvement of a new suspension.
Hazardous situations can also occur due to, for example, instability straight ahead / in corners and/or during braking.
Wheel alignment in Hoyland and the surrounding areas like: Tankersley, Birdwell, Worsbrough, Blacker Hill, Jump, Hemingfield, Wombwell, Brampton, Elsecar, Brampton, Bierlow, Hood Hill