Straight from QLD TPT as follows.
Bulletin dated May 2000 Number 35
Body Lift Kits and Suspension Height Modification
Due to an ever increasing demand for approvals of suspension modifications, Vehicle Standards have released the following policy in regards to this matter.
Body Lift Kits
The maximum allowable height permitted by Queensland Transport has been set at 50millimeteres ( 2 inches).
Suspension Height Modifications
The suspension travel in bump or rebound mode must not be altered by more than one-third of that measurement as specified by the original manufacturer.
It should be noted that both modifications can be performed simultaneously to a vehicle to gain extra vehicle body height but individual specifications must not be exceeded. Modifiers may have to obtain the original bump stop clearances to calculate the allowable acceptable increase. The wheels and tyres fitted to a modified vehicle must continue to compl with the requirements of the Transport Operations ( Road Use Management – Vehicle Standards and Safety ) Regulation 1999.
An individual vehicle modification application to be made to Queensland Transport for body lift kits (blocks between body / cabin and chassis mounts) up to 50 mm in height. Applications must indicate changes made to implement the modification (including steering and braking componentry and materials used in the lift blocks. Body lifts in excess of 50 mm will not be considered.
If acceptable a letter of approval for the installation of a body lift kit will be issued by Queensland Transport
Suspension height modifications carried out in accordance with good engineering practice will be considered acceptable where the suspension travel in the bump or rebound mode is not altered by more than plus or minus one-third of that as specified by the original manufacturer A vehicle modification application will not be required as this is considered to be a self approved modification.
Modifications that involve leaf springs remounted from under axle to over axle are not regarded as an acceptable form of suspension modification and will not be approved
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