Lowering your car is traditionally an easy way to improve handling, as a lowered center of gravity improves the vehicle’s road holding.
- Lowering your car is legal, but there are limits
- If your vehicle is too low, it could be defective or impounded
- Fines may apply for driving an unroadworthy vehicle
However, there are different laws across the country that regulate what you can and cannot do if you plan to lower your vehicle.
Not all states and territories are described in great detail in this story. So if you plan to lower your vehicle but are unsure of what local regulations apply, be sure to consult the appropriate documentation for your jurisdiction and/or or contact a mechanic or vehicle certifier to find out what you can do and what not to do to achieve your ideal result.
The known dimension for lowering vehicles is 100 mm. This is what the Australian Design Rules (ADR 43) state as an acceptable level of ground clearance.
Concrete “Any point in the width of the vehicle that lies within one meter in front of and behind an axle. There must be a distance of 100 mm between the vehicle and a flat surface. However, wheels and mud flaps do not count in this measurement.
The police are there Queensland are well advanced in their approach to this measurement. The Queensland Police Service has a measuring wheel that can determine if a car has less than 100mm of clearance. If you’re not sure whether your car is too low, you can “cut a simple block of wood to 100mm and drive it under your car. A car at home would be an easy alternative.”
Further reading should include the National Code of Practice for Light Vehicle Construction and Modification (NCOP) published by the Australian Government Department of Infrastructure, Transport, Regional Development, Communications and the Arts.
This document contains a set of current, changeable guidelines for vehicle modifications.
The department’s website states: “The National Code of Practice for Light Vehicle Construction and Modification (VSB 14) was prepared by members of the Australian Motor Vehicle Certification Board working group in consultation with industry, user groups, government agencies and individuals with a. “Interested in modifying light vehicles and/or building custom designed light vehicles (ICVs).”
Citing VSB 14, Section LS – Suspension and Steering, it states that “fundamental changes not requiring certification” include lowering a vehicle, provided that the “total change in vehicle height resulting from all changes made: “Does not exceed 50 mm”.
Additionally, the following is fine and does not require certification: “Lowering and raising the suspension (by no more than one third of the original suspension travel, provided the original vehicle height is not increased or decreased by more than 50mm).”
Why do people lower their cars? It could be about improving the driving experience, improving the appearance of the car, or both. Some people will also claim that a lower car offers better fuel economy and efficiency, and while this may have its merits, it won’t fly with a police officer if your exhaust system sparks on the road.
A lowered suspension typically offers a firmer or firmer ride, meaning a stiffer driving experience for the drivers in the car, but the benefit is a more assertive ride and improved cornering dynamics.
Victoria’s Vehicle Standards Information puts it succinctly: “Lowering or raising a vehicle’s ride height by changing its suspension changes its suspension travel. For example, lowering a vehicle by installing shorter springs will reduce the available suspension travel in the “bump” or up direction. Likewise, raising a vehicle by installing longer springs will result in a reduction in the available downward or downward travel.
It’s worth noting that if you have a brand new car or a vehicle that is still under the new car warranty, you should check the fine print on the documentation as a change such as lowering the suspension could void your warranty coverage.
As you might expect, sportier cars tend to be lowered, but there are modification scenes where people lower their small cars or SUVs to achieve a certain stance, and they may achieve this by installing lowered springs (which are shorter suspension springs). E.g. lowering the ride height) or replacing the suspension entirely with a different type of setup – be it coilover suspension or perhaps airbag suspension.
There are other ways to do it. Some vehicles may be equipped with lowering blocks, and some modifiers with vehicles equipped with leaf springs may choose to reduce the number of leaves in the suspension. However, a ute with three leaf springs instead of five would be less able to carry a heavy load, but would look worse if there was a load in the tray.
Another unconventional way to lower a car is to “chop off” the suspension springs – but this is both dangerous and damaging.
However, there are actually rules about how low you can build your car.
In some jurisdictions it is legal to adjust your vehicle’s ride height by +/- 50mm (1.9685 inches), which may explain why the most commonly marketed lowered height for car springs when purchased is “two”. inch lowered spring”.
Another example, in NSW The Light Vehicle Modification Guidelines state that it is legal to adjust a vehicle’s ride height as long as it is done within certain parameters: “Changing the ride height of the vehicle by more than one-third of the manufacturer’s travel in the direction of the ride height change.”
The guidelines also state that you do not need certification (signed by a person accredited as a licensed certifier under the TfNSW Vehicle Safety and Compliance Certification Scheme). [VSCCS]), for the following:
- Suspension modification with components or parts that meet or exceed the original vehicle manufacturer’s specifications
- Installation of upgraded roll bars, shock absorbers, springs, struts or manufacturer options for that year’s make and model
However, there are some larger tasks that require approval from a certifier, including:
- Conversion from coil to leaf springs
- Any change in suspension configuration
- Installation of a suspension of a different design, e.g. B. a different brand and model (e.g. from coil springs to leaf springs)
- Making suspension attachment points
There is a uniform regulation across the country regarding the permissible driving height: a minimum driving distance of 100 mm is required. If you have a lowered car that runs but only has 90mm of ground clearance, you will face a defect and/or a fine.
For airbag suspension, Victoria states that it is “acceptable” as long as it is certified (VASS Approval Certificate) and as long as: “the ride height of a single wheel or axle cannot be changed while the vehicle is in motion; For all selectable ride heights, at least two thirds of the original suspension travel is retained in both directions while driving; The original posture of the vehicle is maintained while driving in all selectable ride heights.”
Vehicles with airbags must also maintain a minimum distance of 100 mm while driving and when parked.
As previously mentioned, depending on where you live, there are more specific details about cutting rules and laws. If you intend to lower your car, make sure you do so legally and responsibly.
Not intended as legal advice. Check with the relevant highway authority in your state or territory.