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Anti-Roll Bars

ARB Page

Configure anti-roll bars (ARBs) for front and rear axles. ARBs resist body roll by coupling left and right wheel movements, redistributing lateral load transfer between the front and rear axles.

ARBs are optional — they are toggled on or off independently per axle. When disabled, no roll stiffness contribution is added from the ARB.

Parameters

Parameter Description Unit
Stiffness Torsional stiffness of the anti-roll bar Nm/rad
Damping Coefficient Damping rate of the anti-roll bar Ns/m
Motion Ratio Installation ratio between ARB twist and vehicle roll (see below) -

ARB Motion Ratio

Unlike spring and damper motion ratios (which are calculated from kinematics geometry), the ARB motion ratio is entered directly on this page. This is because the ARB linkage geometry is typically independent of the main spring/damper actuation.

The ARB motion ratio is the ratio between how much the anti-roll bar twists for a given amount of vehicle roll:

Motion Ratio = ARB Twist Angle (rad) / Vehicle Roll Angle (rad)

It is a unitless value. A higher motion ratio means the ARB twists more for a given amount of vehicle roll, making the roll stiffness contribution effectively higher.

The effective ARB rate at the wheel is:

ARB Rate = Stiffness x Motion Ratio²

Similarly, the effective ARB damping rate at the wheel is:

ARB Damping Rate = Damping Coefficient x Motion Ratio²

Validation Warnings

Condition Warning
Stiffness is zero Zero stiffness — ARB has no effect
Stiffness > ~500,000 Nm/rad (~8.7 kNm/deg) Very stiff anti-roll bar
Motion ratio < 0.3 Very low motion ratio
Motion ratio > 2.0 Very high motion ratio