7 FRONT SUSPENSION
VERTICAL PRELOAD ADJUSTMENT
Remind there is always some ‘pre-load’ in the damper: typically this is around 7-8kg for the
standard Koni damper. This ‘pre-load’ depends on damper make, type and the internal gas
pressure.
In a non pre-load condition, as long as the damper is not fully extended, turning the
platform C only changes the car ride height (and lowers the pressure inside the damper).
When the damper gets fully extended, turning on the platform C increases vertical spring
pre-load on the car. We advise though, not to proceed this way, because some dampers
(including Koni) should not be used fully extended. Therefore we advise to use, for both
mono and twin configurations, the droop-stop (A).
Pre-load in this text is considered to be the necessary force that has to be applied to the
spring to change its length with respect to the static length value.
P = Ks x t x 2
P = pre-load in kg
Ks = spring stiffness in kg/m [(Ks in Lb/in) / 56 = Ks in kg/mm]
T = number of platform (C) turns
2 = mm / turn (for standard Dallara Koni damper top)
SETTING PRE-LOAD (for mono and twin configurations)
• Mount the damper-spring combination with the platform C just in contact with the spring
• Put the car including its driver on the set-up floor
• Screw the droop-stop A away from touching bolt B
• Adjust ride height with the pushrod adjusters to the desired setting
• Bring droop-stop A in contact with bolt B
• Turn platform C until desired pre-load force is achieved. (P = Ks x t x 2)
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