Wheel alignment involves adjusting the angles of a vehicle's wheels so that they are perpendicular to the road surface and parallel to each other. This allows the vehicle to travel in a straight line with equal stress on each side. Key alignment angles include camber, caster, and toe. Proper wheel alignment provides benefits like reduced tire wear, better gas mileage, smoother riding, and improved safety and handling.
2. INTRODUCTION
WHAT IS WHEEL ALIGNMENT
IMPORTANCE OF GOOD WHEEL ALIGNMENT
WHEEL ALIGNMENT ANGLES
BENEFITS OF WHEEL ALIGNMENT
DANGERS OF WHEELS THAT ARE NOT
ALIGNED
4. WHAT IS WHEEL ALIGNMENT
The alignment is concerned with the wheels being perpendicular to
the surface of the road and that the wheels are parallel to each
other. This means that the car will drive evenly. It allows the vehicle
to go down the road as straight as an arrow with no one side being
overly stressed. Proper alignment can also allow for quicker stops
and a shorter distance to cause that stop.
5. IMPORTANCE OF GOOD WHEEL ALIGNMENT
Wheel alignment increases efficiency of vehicle
GOOD WHEEL ALIGNMENT
Wheels are
perpendicular to
road
Wheels are parallel
to each other
VARIOUS ANGLES OF ALIGNMENT
Caster Camber Toes
7. WHEEL ALIGNMENT ANGLES
CAMBER: It is the angle of the wheel, measured in
degrees, when viewed from the font of the
vehicle. If the top of the wheel is leaning out from
the centre of the car, then the camber is positive,
if its leaning in, then the camber is negative. If the
camber is out of adjustment, it will cause tire wear
on one side of the tires tread. If the camber is too
far negative, for instance, then the tire will wear
on the inside of the tread .
8. Caster: When you turn the steering
wheel, the front wheels respond by turning on
a pivot attached to the suspension system.
Caster is the angle of this steering pivot,
measured in degrees, when viewed from the
side of the vehicle. If the top of the pivot is
leaning toward the rear of the car, then the
caster is positive, if it is leaning toward the
front, it is negative. If the caster is out of
adjustment, it can cause problems in straight
line tracking. If the caster is different from side
to side, the vehicle will pull to the side with the
less positive caster. If the caster is equal but
too negative, the steering will be light and the
vehicle will wander and be difficult to keep in a
straight line. If the caster is equal but too
positive, the steering will be heavy and the
steering wheel may kick when you hit a bump.
Caster has little affected on tire wear
9. Toes: The toe measurement is the
difference in the distance between the
front of the tires and the back of the
tires. It is measured in fractions of an
inch in the US and is usually set close to
zero which means that the wheels are
parallel with each other. Toe-in means
that the fronts of the tires are closer to
each other than the rears. Toe-out is just
the opposite. An incorrect toe- in will
cause rapid tire wear to both tires
equally. This type of tire wear is called a
saw-tooth wear pattern as shown in this
illustration.
10. Steering axis inclination or kingpin (KPI): The steering axis inclination is the
tangential deviation of the pivot axis with respect to a vertical line to the roadway (seen
from the vehicle steering axis). Steering axis inclination and camber together form an
angle that remains the same upon deflecting in
11. Toe out on Turn or Turning Radius:When you steer a car through a
turn, the outside front wheel has to navigate a wider arc then the inside wheel.
For this reason, the inside front wheel must steer at a sharper angle than the
outside wheel.
12. Thrust Angle:The angle between the vehicle's centerline and the vehicle
thrust line. When driving, the front wheels and the rear wheels should pull to
the same side if the thrust angle is not zero. When thrust line is at the left side
of the vehicle's centerline, the thrust angle is positive, otherwise is negative
13. Scrub Radius:Scrub radius is the distance between where the SAI intersects the
ground and the center of the tire. This distance must be exactly the same from side to
side or the vehicle will pull strongly at all speeds. While included angle problems will
affect the scrub radius, it is not the only thing that will affect it.
14. Included Angle: Included angle is the angle formed between the SA and the
camber. Included angle is not directly measurable. To determine the included angle, you
add the SAI to the camber. If the camber is negative, then the included angle will be less
than the SAI, if the camber is positive, it will be greater. The included angle must be the
same from side to side even if the camber is different. If it is not the same, then
something is bent, most likely the steering knuckle.
15. BENEFITS OF WHEEL ALIGNMENT
Reduce wear on tires
Better gas mileage, due to less work on the engine
Smoother driving, lack of vibration at high speeds
Straighter driving with no pulling to one side or the other
Improved safety
Shorter stopping distance
Safer Driving
Save Money & Environment
Improve fuel consumption, brake & Steering condition
Maximum tire life and a vehicle that tracks straight and true when driving
along a straight and level road