Wheel alignement; geometry and parallelism
Unless you are an expert driver with advanced skills in car mechanics, as well as having the adequate tooling, geometry settings should not be tampered with. Every vehicle has a unique combination of settings for optimal performances for the camber angle, caster angle and the toe in.
Geometry consists in setting and make sure all the wheels have the proper setting. The operation costs between 50 and 100gbp
Yes, the costs involved in alignement controls are quite high, but it is a necesary evil since wrong settings can drastically reduce the lifespan for your tyres and might result in an unpleasant driving experience.
Before getting into technical details, let's introduce the main questions about alignement
Should I check alignement as often as oil?
Not at all, geometry is a special procedure that needs to be requested only in the following cases :
- When your car veers to the left or right.
- If the tyres display irregular wear.
- When the steering wheel doens't go back to neutral
- When the tyres emit worrying sounds.
Should I check geometry whenever I replace/ rotate my tyres ?
Generally speaking, checking geometry when replacing tyres is not a compulsory procedure ( but you have to get your tyres balanced on the wheels) It is not compulsory to check geometry when you keep the same sizes but geometry becomes compulsory when you want to move away from the original sizes. As a matter of fact, most car mechanics will offer you this service, just to make sure everything is in order.
What is alignement exactly ?
Wheel alignement includes the following measurement checks/ settings : camber, castor and toe-in/out
The settings for each individual car is very precise and each mm matters. Afficionados like to change the settings to order to make their car adopt specific behaviours on the road. Most of the time and for precision's safe, High tech alignement machines are used, but DIY tools are also available on the market
Camber is expressed in degrees, it is the tilt of the top of the wheel inward or outward
For sport driving, camber is generally negative for more efficient contact patches in turns. However, negative camber also affects the contact patch negatively in straight lines.
It is also expressed in degrees, the caster angle is almost invariably positive in order to ensure the forward motion of the vehicle. Even racing pilots barely modify the caster angle. It is usually modified to regain the good values after an accident or shock.
Toe-in / parallelism
The toe-in ( or toe- out) corresponds to the left/ right alignement of the front wheels relative to each other. When they point away from each other, we speak about toe out, whereas when they point toward each other, toe-in is used.
In order to adapt to the mechanical forces that influence a moving vehicle, toe in and toe out settings depend on whether you car is a front or a rear wheel drive. Front wheel drive should have a little toe out. Rear wheel drive should have a little toe in.
In conclusion, you should always bear in mind the importance of proper alignement settings
Never mind if you are equipped with the latest , state of the art tyres, as if your settings are wrong, your tyres will suffer from it in no time.