ByEvan SpenceApril 13, 2016


For the majority of us, suspension modification has always been a grey area in terms of legalities, differing state and federal regulations, and what we are and aren’t allowed to do to our suspension in order to improve vehicle safety, towing ability, ground clearance and load-carrying capacity.

But rest assured, the Australian 4 Wheel Drive Industry Council (A4WDIC), which is a specialist section of the Australian Automotive Aftermarket Association, has been busy in the background.

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Until recently, the national Vehicle Standards Bulletin (VSB 14) stipulated that any vehicle fitted with electronic stability control (ESC) and which had any increase in vehicle height (tyres, suspension etc) must be certified to ensure the ESC was not affected.

However, after extensive testing, the A4WDIC has recently been successful in changing the national regulation which had previously required the additional certification.


The testing, conducted both in Australia and in the US, involved modifications to three popular vehicles. The Ford Ranger, Toyota LandCruiser and a Jeep Wrangler were all modified using suspension kits from Australian aftermarket suppliers and were tested alongside identical non-modified vehicles.

The same test protocols used by vehicle manufacturers and major component suppliers around the world were employed to simulate vehicle dynamics for the development and testing of new chassis system components, engines, power trains, drivelines, suspension setups and vehicle electronic control systems.


Ray Smith-Roberts from A4WDIC said: “In all cases the test results were well within the normal operating capabilities of the vehicles’ ESC systems and ADR 35 requirements.”

As a result, the National Code of Practice has been amended to remove reference to ESC testing requirements for vehicles with suspension height modifications of up to 50mm.

Proof that with the right approach and the right attitude towards change, common sense can prevail.

Well done A4WDIC!