Lotus Evora, Service Notes

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Page 6
Lotus Service Notes Section CK
Cambolt illustration
Castor Adjustment
Castor is the angle from vertical of the steering axis of the wheel when viewed from the side. Its primary
purpose is to provide a natural straight running tendency of the steered wheels with forward vehicle motion.
Castor angles have a complex interaction with other steering geometries and if unbalanced or outside of speci-
fication, can result in various stability and handling deficiencies.
The eccentric cams fitted at both front and rear inboard pivots of the lower wishbone (see 'Camber Ad-
justment above) are also used to adjust camber. By moving the rear pivot axis outwards, and the front pivot
inwards, the lower swivel joint is moved forwards to result in an increase in castor angle. To reduce the effect
of this adjustment on camber angle, the front pivot point will need to be moved laterally about three times the
distance, and in the opposite direction, to the rear pivot point movement.
After adjustment, ensure that the nuts are tightened to 86 Nm (only at ride height).
CK.3 - WISHBONE PIvOT BUSHES & SWIvEL JOINTS
Pivot Bushes
The upper and lower wishbone pivot bushes are bonded rubber type with a plastic flanged outer sleeve,
an alloy inner sleeve, and an aluminium interleaf sleeve within the rubber bush to control the flexing character-
istic. The rubber material specification has been selected to optimise the handling/refinement balance. The
flanged end of the bush incorporates a snubbing feature to limit the axial distortion of the bush, with each bush
arranged to resist braking forces transmitted through the suspension; Both top wishbone bushes are inserted
from the front, and both bottom wishbone bushes from the rear. A chamfer is provided in the wishbone bore
for this purpose.
The bushes may be pressed out of the wishbone eyes, and new bushes fitted using suitable press tool
dollies. Smear the outer surface of the new bush with IPC 'P-80' rubber lubricant emulsion (A082C6042v) to
ease fitment, and assemble in the direction detailed above.
FRONT
Top & bottom
steering swivels
Vertical Castor angle
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