F/R damping coefficient ratio, pitch coupling

[WilO]

I'd be grateful for any insight regarding the ratio of front to rear damping, and the amount of pitch/heave coupling present; ie. if the front axle has the greater damping coefficient, would this cause an increase in pitch coupling? Obviously spring rate figures into this as well, I'm just wondering if there is any correlation with respect to damping.

Thanks in advance.

Wil

[GSpeedR]

Wil, the best way to understand is (unfortunately) to derive the equations for a simplified 2 DoF car with pitch and heave degrees of freedom. Sum forces (F=ma) for heave and sum torques (T=I*alpha) for and you will have two coupled differential equations.

There are coupling terms in both equations, which will appear as (Lf*Kf - Lr*Kr) and (Lf*Cf - Lr*Cr), where L is the distance between cg and axle, K is ride stiffness and C is ride damping. These coupling terms are what you are after it seems. If both of these terms are zero then the two equations are uncoupled and responses will be independent (ie pitch input only results in pitch response). If you prefer matrix formulation, the cross-terms (non-diagonal) of the stiffness and damping matrix are the coupling terms.

[WilO]

GSpeedR,

That helps, thank you for taking the time.

Wil