Maintaining correct wheel alignment is paramount for decreasing unnecessary tyre wear and preserving suspension components. Properly aligned wheels ensure that each wheel complements the other and is optimised to provide good vehicle stability and traction. There are basically 3 components: Camber, Castor and Toe that can be tweaked so as to get the perfect setting for your vehicle. Vehicle manufacturers choose these settings after spending lot of time in R&D center. Therefore, that should be the ideal settings you should go with on public roads, unless you want to modify your car for racetrack competition. Without further ado, lets discuss these 3 components of wheel alignment-
Camber is the angle between wheels vertical alignment and an imaginary perpendicular line from the tyre contact surface. When the wheel is perfectly perpendicular to the road surface then the camber is said to be 0 degrees. Camber is said to be negative when the upper part of the tyre tilt inwards. Similarly, if upper part of tyre tilts away from the car, then it is said to be positively cambered.
Negative and positive camber alters a car’s handling differently. Negatively cambered car will provide more grip while cornering but at a cost of reduced contact surface while going straight. Positive camber reduces steering effort and helps the wheels to self align in straight direction, after the turn has been made. Zero camber will provide maximum contact patch on straights and therefore improves acceleration and braking performance.
Caster angle is the angle between the pivot line(imaginary line that runs through the center of upper ball joint to center of lower ball joint) and a vertical line. Castor is said to be positive if the line makes a forward inclination. Castor is negative if the line is inclined backwards.
Generally, positive angle increases high speed stability and tyre lean while turning but, this comes at a cost of increased steering effort.
Toe angle is angle derived when wheels points inwards or outwards when viewed from a top down position. Toe is said to be positive when both the tyres starts tilting towards each other. Positive toe increases the straight line stability but reduces cornering ability. Generally, rear wheels drive cars have slight positive toe angle as on the move the wheels gets straightens, this improves rolling resistance. Toe is said to be negative if the tyres diverge away from each other. Negative toe angle in front wheel drive cars compensates for the understeer by inducing extra oversteer. Generally, toe-in improves the car’s straight line stability and toe-out improves the steering response.
Also see: Importance of wheel alignment