7 FRONT SUSPENSION
VERTICAL PRELOAD ADJUSTMENT
Remind there is always some ‘pre-load’ in the damper: typically this is around 10kg 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 raises the 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 the droop-stop A.
Pre-load is the necessary force that has to be applied to the spring to modify 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 damper top)
SETTING THE PRE-LOAD
• Mount the damper-spring combination with the platform C just in contact with the spring
• Put the car including the 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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