Originally Posted by NSW RTA
Suspension
Besides assuring a comfortable ride, a vehicle’s suspension system controls wheel movement for handling and road
holding. Manufacturers conduct extensive test programs to develop suitable suspension settings. Adjustments, such
as lowering the vehicle, can upset the suspension characteristics and cause unpredictable handling. Generally, roll
stabilizer bars, axle locating rods, upgraded shock absorbers or upgraded springs may be used provided they are
suitable for the vehicle and are properly fitted. However, the following suspension modifications are not acceptable:
Welding forged components such as stub axles or control arms.
Fitting longer, non-standard shackles to leaf springs.
Fitting any additional components or altering the suspension so that the wheels or tyres may contact any
component under the full range of suspension and steering travel.
Fitting any additional components or altering the suspension ride height so that any part of the vehicle other
than a wheel or tyre can contact the road in the event of a tyre deflation.
If major changes to the suspension (such as substitution of a non standard front cross member) are carried out, they