Duncan Gay, the Minister for Roads, Maritime and Freight in NSW, has recently announced via Facebook, that the laws surrounding vehicle suspension lifts have changed.
VSB 14, the laws which control suspension modifications, and particularly 4X4 suspension lifts, has been the target of a working ground lately, because they were identified as being “too onerous, restrictive, impracticable to apply, or simply unsafe”.
Previously, there was a blanket 50mm ceiling on increasing the overall height of a vehicle, whether it was via changes with suspension or tyres.
Now, you can lift your 4X4 a total of 75mm: 50mm through the suspension, and 25mm through the tyres. Big, silly lifts are still out of the question, but many looking to subtly modify their 4X4 for better touring or off-road performance now have some nice scope for suspension and tyre modifications.
On top of this, you can also run through other detailed assessments before haivng to submit to a ‘potentially dangerous’ lane change manoeuvre test. It also gives some guidance on airbag and variable suspension, something that VSB 14 didnt really cover at all.
Importantly, one thing we like is that the VSB 14 update also gives you guidance on measuring your ride height, so you can actually have a baseline to work from for a 4X4 suspension lift. vehicle modification laws in Australia have always had the problem of being very strict, but also being unclear, unrealistic, or even some cases completely self- contradictory and oxymoronic.
Let’s look at a couple of case studies. You want to modify the suspension of your Toyota HiLux (or for that matter, 90% of 4WDs on the road (dual cab utes)? Let’s look at the nuts and bolts.
Your able now to fit, without needing to approach any problems of engineering or legality, 95% of suspension kits out there. Most cater for that basic 50mm (2 inch) lift, something that the respective sellers should be able to clarify you. If not, take your money somewhere else.
Let’s look at tyres. A HiLux SR5 sports 265/60 R18 rubber. That’s 775mm, 0r 30.5″ roughly (every tyre is a bit different). Increasing your ride height up 25mm means a 50mm increase in tyre diameter. So, that’s up to 825mm in total diameter, or 32.5 inches in the old money.
These laws are dependant on the actual, real-world diameter of the tyre, so depending on the actual size and tread depth, you could potentially go to something like a 285/65 R18. Online websites list this diameter at 827.7mm, 2mm over. But the real-world tyre size needs to be figured out for an actual answer.
At any stretch, it’s a good news story. Increasing your tyre diameter gives great benefits for off-road driving, but don’t forget the negatives: increasing your ride height affects your centre of gravity, which has many knock-on effects on and off-road. And going up a tyre size is bad for your braking and off-road gearing. A 4X4 suspension lift is a good modification to make, but make sure you walk down the path of modification with your eyes wide open.
11 comments
Wow still can’t run a 33″ or 285/75/16 on a patrol legaly!
I have over forty years experience in four wheel driving in all terrain encountered in Australia. I cannot understand how, after so much research that authorities can take a retrograde step in safety by increasing legal lift over 50 millimeters.
A modern 4×4 dual cab ute can be rated to tow 3500 kgs. With manufacturer spec tyre sizes, many of these vehicles can and do struggle to have sufficient down force on the road to stop or maintain traction in an emergency. Increased footprint exacerbates these deficiencies even further.
Insurance companies cannot, and will not abide a minister of government seeking to retain his/her seat by appeasing the gung ho and approve claims when (repeat when) those who step outside manufacturers specs come to grief.
I have witnessed too many 4×4 loss of driving control incidents with caravans and trailers to believe that this is commendable.
Sorry leon but I dont understand how a bigger foot print could reduce down force
It doesn’t. Leon’s a muppet
1st – I do own & drive a 4×4 with a 2″ lift kit & I tow a 2.8 tonne van , large boat & trailers , & an ex truckie , & have been driving these for almost 50 years. so to guys like Fuzzy-Bear that probably also make me a Muppet or maybe just “A Silly Old Fart ” π
as LEON , Silly Old Fart or not I agree with you mate , these laws made by “The Minister for Roads, Maritime and Freight in NSW” who most likely drives an Office Chair & has no real experience in what he is making laws about .. , Personally I think the whole thing including Licencing need to be looked at , you can NOT drive a Truck & Trailer combo or Semi Trailer with the right licence , but as soon as you are off “P” plates you can hook up a 3.5 tonne van or trailer onto a radically lifted 4×4 & off you go , no experience or licence or testing other than a car licence !!!
AS for you LEON trying make these guy like Fuzzy-bear understand what you are actually saying , you would have to spend a lot of time trying to explain & educate them , as they obviously don’t understand much about “Centre Of Gravity ” tyre contact patch, breaking & transferred weight when towing a large van or trailer ect ect the list goes on !! , & If thy actually read the write-up above they would have seen where it says
” But donβt forget the NEGATIVES : increasing your ride height affects your centre of gravity , which has many knock-on effects on and off-road. And going up a tyre size is bad for your braking and off-road gearing ” .
As for Leon being a Muppet , I think its easy to see who is the Muppets !! they are usually the ones with the shiny side down π
Merry Christmas guys & girls , safe 4×4’n
Actually, the comment by Anonymous is fair enough, and the one by Fuzzybear is half right.
Force is a function of mass, so the down force is unchanged.
Downward pressure is reduced by a bigger footprint, but downward force is not.
And friction is usually a function of normal (perpendicular) force, not of pressure (except in snow).
From there, it gets complicated, as Nifty suggests.
But, if an increased footprint really did exacerbate a traction deficiency, then dragsters would need to re-think their tyre choices.
Amaroo, bringing dragsters into the discussion we have an entirely different purpose.
A drag car design purpose is such for entirely short lived temperature, grip, ability to withstand max rotation from extremely powerful engines, to match rolling diameter in lowest possible timeframe over a restricted distance.
Low centre of gravity for stability of the various forces produced and deliberate design of nil braking, turning capacity under load or speed to achieve that limited straight line distance.
No way you could imagine that style of design on a public road let alone off road.
Look at monster trucks high centre of gravity, big everything imagine that style on a public road and that image is what drives some to believe it’s ok.
I see a lot of rollovers on the Bruce Hwy the majority are high 4×4 or 4×2 travelling at speed 110kms per hour, making short/sharp lane changes on AT tyres aided by distraction of some sort a common link.
In the opposite end you have the image of big dia wheels low profile tyres, hand cut coils that the body is so low the front wheels cannot turn as designed but seemingly owners think it’s ok because they did it and then blame law authorities policing their stupidity.
You have to have sensible legislation to protect ALL road users and especially those that the “about me generation” ignore, but even then such sensible laws continue to be snubbed.
Insurance companies won’t cover that risk and soon they could well stop paying out the insured driver that is the victim.
I think education and learning how hi lift vehicles drive would be important as well as towing trailers. Mates girlfriend had not long had her full license and she wants to tow a big ass caravan around nsw. She never had any experience in this area and has driven a ford focus around town all her driving life. I pointed out handling issues and braking and wind resistance with oncoming trucks and the like. She had no idea and still thinks its sll fine
Great, Air springs look pretty much promising. Thanks for the share & step by step guide to install.
all a load of shit, any vehicle any mod cannot be deemed safe and legal in one state or country and not another, what are the people in the states or nsw super human if its safe for one man or woman to drive then it cannot be deemed unsafe for another man or woman, wake up people do what modification you like to your cars trucks bikes boats and if fined take it to court on these grounds- WIN
My D40 in qld aus 6” rough country suspension lift 2” body rolling 0n 24s with 35” muddies.
Explain yourself Jono,thats doesn,t sound right !