Steering Geometry

1. ◾CASTER ANGLE
◾CAMBER ANGLE
◾STEERING AXIS INCLINATION
◾TOE
◾THRUST ANGLE
◾TURNING RADIUS
◾SUSPENSION HEIGHT

2. CASTER ANGLE
Angle between vertical line and
centre line of king pin
FUNCTIONS
◾ SELF CENTRING
ACTION
◾ STRAIGHT LINE
STABILITY
◾ EXCESSIVE CASTER
MAKES STEERING
HEAVIER, LESS
RESPONSIVE AND
INCREASED EFFORT

3. FUNCTIONS
◾ +VE CAMER LOWER
STEERING EFFORT
◾ -VE CAMBER
IMPROVES GRIP
◾ EXCESSIVE CAMBER
CAUSES INCREASED
TIRE WEAR, REDUCES
STRAIGT LINE
ACCLERATION
Inward and outward lilt
of wheel (from F.V.)
CAMBER ANGLE

4. ANGLE BETWEEN VERTICLE LINE AND
KINGPIN CENTRE LINE (From F.V.)
FUNCTIONS
◾ HELPS IN
STEERING
RETURNABILITY
AFTER A TURN IS
COMPLETED
◾ REDUCES
STEERING EFFORT
◾ REDUCES TIRE
WEAR

5. SYMMETERICANGLE B/W
WHEELSANDAXISOFVEHICLE
 TOE IN INCREASES
STRAIGHT LINE
STABILITY AT
COST OF TURNING
RESPONSE
 GREATER THE TOE
FASTER THE TIRE
WEARS
FUNCTIONS

6. TOE-IN TOE-OUT

7. Angle between Geometric line
and Thrust Line
◾ OCCURS WHEN REAR
WHEEL HAS
IMPROPER
ALIGNMENT
◾ EFFECTS DIRECTION
OF TRAVEL BY
CAUSING PULL IN THE
DIRECTION AWAY
FROM THRUST LINE
FUNCTIONS

8. Turning circle radius = (track/2) + (wheelbase/
sin(average steer angle))
The turning circle of a car is the diameter
of the circle described by the outside
wheels when turning on full lock.

9. ◾ SYSTEM AUTOMATICALLY STEERS THE REAR
WHEELS ACCORDING TO SPEED OF VEHICLE
AND STEERING ANGLE.
◾ USED IN MILITARY, OFF ROAD VEHICLES,
BUSES, TRUCKS AND LARGE VAHICLS
◾ INCREASES HANDLING AND
STABILITY
◾ REDUCES TURNING RADIUS

11. ◾ VEHICLE STEERS BY POWER ASSIST
FROM EXTERNAL SOURCE OTHER
THAN DRIVER’S EFFORT
◾ HELPS IN STEERING OF HEAVY
VEHICLES
◾ INCREASES THE STEERING RATIO
AND REDUCES DRIVER’S EFFORT
◾ TWO MAJOR TYPES – HPS AND EPS