Wheel alignment (or tracking) is probably something most people only think about after an MOT failure or after changing suspension – but after your brakes and tyres it’s possibly the most important thing between you and the road and deserves a regular check-up!
But what is it?
In an ideal world your car would come out of the factory straight and true – and after years of driving on a perfect road surface it would still be 100%. Unfortunately our roads are far from ideal and every single pothole and speed ramp will knock out the alignment slightly.
Camber is the angle of the wheel – if the top of the wheel is tilted out then it has positive camber, if it’s tilted in it has negative camber – These can also be adjusted to suit specific handling requirements for motorsport or offroading.
Toe is the most critical for tyre wear. This is the direction of the wheels when compared to the centre line of the car.
In simple terms, your wheels go from facing 100% straight to being slightly angled to either side after time. Manufacturers guidelines will set out the exact angle the wheels should be at – e.g. front wheel cars are generally set up with “negative toe” to compensate for the fact that they pull the vehicle along and rear wheel drive cars will have “positive toe” as they push the car.
What it means is that for every 4mm (2 mm per wheel) your tracking is out your tyres are being forced sideways 8.4 metres in every mile – which leads to excessive tyre wear and will hurt your bank account more than spending the cash to get your tracking checked in the first place!
Caster is the tilt of the steering axis – it generally can’t be adjusted on front wheel drive cars and has little or no effect on tyre wear. If your caster is negative the steering will be very light and difficult to keep in a straight line. If it’s positive the steering will be very heavy.
How do you know if your wheel alignment is out?
On a straight flat road your car should go in a straight line by itself…..
Don’t try this at home – but if you were to let go of the steering wheel it would keep travelling in a straight line by itself and wouldn’t pull to one side.
In other words you shouldn’t have to struggle with the steering or try to “hold” the car in a straight line. Another test is through braking – the car should brake in a straight line and shouldn’t veer to either side.
Saving on tyres isn’t the only good reason to get your tracking checked! It can improve your handling and braking ability – and speaking from experience you don’t want to hit a big puddle if your alignment isn’t 100% and judging from recent weather conditions those large puddles are here to stay!
(It’s also important to check your tyre pressures regularly – if one wheel is down the car will pull to one side).