dallara F308, Руководство пользователя, Страница: 8 / 40

FRONT CASTOR ANGLE SETTING 8
When the car is flat , that is with the same front and rear ride height:
¾
WMP: when the upright inclination angle (apparent castor) is +2.10° the castor angle (build
in castor) is 10.60° . The upright reference plane points downwards in forward direction.
¾
UMP: when the upright inclination angle (apparent castor) is -2.80° the castor angle (build in
castor) is 13.50° . The upright reference plane points upwards in forward direction.
Drawing shows
UMP
CASTOR 13.50°
HORIZONTAL
UPRIGHT
REFERENCE
TRAVEL DIRECTION
When the car has a pitch angle , that is with different front and rear ride height.
For instance, with FRH 15mm and RRH 30mm the pitch angle equals:
[(30-15)/2730] x 57.29 = 0.31°
¾
WMP: the upright inclination angle (apparent castor) is 2.10° + 0.31° = 2.41° and the
castor angle (build in castor) becomes 10.60° - 0.31° = 10.29° .
¾ UMP: the upright inclination angle (apparent castor) is -2.80° + 0.31° = 2.49° and the
castor angle (build in castor) becomes 13.50° - 0.31° = 13.19° .
REAR
The rear wheel ‘castor’ angle can be measured to check bump steer to be zero. You can measure
the angle on the brake calliper mounting platforms. When the car is flat (front ride height is equal to
rear ride height) and you measure ‘apparent’ castor of 23°, the ‘castor’ angle is 16° and bump steer
is zero.
The castor angle on the rear axle is, other than for the bump steer control, not relevant since the
rear wheels are not turning.