Maximum legal lift and tyre/wheel sizes in Oz

have been reading through all the government infrastructure docs today and i am still confused :lol:

the reason being is this one section of the doc
"4WD passenger vehicles specifically designed for off-road use (typically MC ADR
category). All wheel drive (AWD) vehicles including those AWD vehicles that may be certified as MC ADR category, (also commonly known as soft roaders) are not
included in this category"

now the reason why i am confused is that our forester are stamped MC which in every other document states, that this means its is a offroad vehicle and must comply with the offroad vehicle regulations. i went and spoke to vic roads about this before and they said that what ever is stamped on the compliance plate (MC in our case) is what the car is and must comply with.
i told her about the document said and she said that it doesn't make sense to her either :lol:

she said she would ask subaru themselves as they should know which regulations the car must comply with.
 
Gidday Thunder

thunder039 said:
have been reading through all the government infrastructure docs today and i am still confused :lol:

the reason being is this one section of the doc
"4WD passenger vehicles specifically designed for off-road use (typically MC ADR
category). All wheel drive (AWD) vehicles including those AWD vehicles that may be certified as MC ADR category, (also commonly known as soft roaders) are not
included in this category"

now the reason why i am confused is that our forester are stamped MC which in every other document states, that this means its is a offroad vehicle and must comply with the offroad vehicle regulations. i went and spoke to vic roads about this before and they said that what ever is stamped on the compliance plate (MC in our case) is what the car is and must comply with.
i told her about the document said and she said that it doesn't make sense to her either :lol:

she said she would ask subaru themselves as they should know which regulations the car must comply with.
Click to expand...

Yeah, I know it's a joke, Joyce, but in one's dealings with the coppers and insurers, the most restrictive interpretation they can find is what applies. Also, the compliance certificate issued to the manufacturer for the Compliance Plate is less than a page long ...

A cautionary tale follows ...

A long time ago, I fought a case about running a red light (I didn't - I ran a yellow light, and the Magistrate agreed that it was the safest thing to do in the circumstances). The Magistrate (God bless his soul; at least after he has died, and may that be a long time coming ... ) found that the offence was proven (not a sentence that was open to him at Law, as we are not in Scotland ... ); that no points be deducted; that no fine was payable; that no costs were payable; and that no conviction be recorded. I have a court document that states all of the above.

About five years later, the coppers brought this up as a prior conviction ... Speaks for itself, really.

The original story is a lot longer and more convoluted than this, including that the Officer in Charge of the Traffic Camera Office lied to the Police Minister, in writing ...
I said to the Magistrate "The best possible interpretation that can be put on Snr Sgt Ritchie's letter to the Police Minister is that he has 'inadvertently misled a Minister of the Crown, Your Worship, but I can think of other words to describe his actions'. So can I Mr ******." said His Worship!
Nearest I have ever come to having a member of the Judiciary call a copper an out and out liar ...

Snr Sgt Ritchie has since been awarded an Order of Australia ...
That also speaks for itself, IMNSHO!
 
yep its a total joke no one knows whats going on!
i spoke to subaru the guy said while the car is stamped MC he would not risk it with increasing the tyre size above 15mm as he said if something were to go wrong, it could go either way... he then also said that it is very confusing and said that every person you speak too will likely tell you something different
 
It's all a load of rubbish. Hence why I don't give a **** There's so many rules and regulations in the country that you practically can't do anything anymore!
 
DedmanWalking said:
Exactly!! Sick of Australia being such a nanny state :sad:
Click to expand...

I do believe in regulation...there are way too many idiots out there who are quite happy to risk their own lives PLUS ours with their stupidity so we need regulation to keep them & us safe. But there needs to be a balance & sometimes that balance is so far off its not funny! Speed cameras are a good point...not a safety device just a source of revenue :yell::furious:
 
Gidday NL

You're right, there is a balance, and it's sometimes hard to find - so I have some sympathy for the law makers there.

However, it's also flaming difficult to wean them off that most addictive of drugs - MONEY ...

Reminds me of the registration of motor boat drivers in SA - a very necessary thing.
Started off that there would be a once off charge of $5 (back in the 1970s ... ) to cover the cost of issuance.
Then it became an annual fee ...
Then it became an indexed annual fee ...
Then it inexplicably jumped by about 10 times the indexation factor ....

:shrug: :shrug: :shrug:
 
Another aspect to lift & suspension damage

Gidday Folks

As Venom raised in another thread, the higher the lift, the greater the load in or on the vehicle, the greater the chance of bending a strut or breaking suspension parts.

I was thinking about this last night (I know, I know ... I don't need any erudite comments on my thinking prowess; or lack thereof ... :iconwink: :lol:).

It occurred to me that weight in the vehicle, or more specially hanging off the back bumper area, puts greater torque on a lifted vehicle than it does on the same vehicle with no lift.

The process is the same as trying to twist something with your hands held close together, or with your hands held further apart.

It is this torque applied by the load at the apex of the triangle ("A" - over the rear bumper) acting at the points of the triangle between the top and bottom mounting of the strut ("B" and "C").

The greater the distance between the top and bottom mounting points, the greater the torque applied. Seems to me that this would be a square law relationship. That is, if the distance B->C increases by 25%, and the load remains identical, the torque applied would be 1.25^2, i.e. (5/4)x(5x4), or (5x5)/(4x4) = 25/16 = 1 9/16; a 56% increase in torque applied over the line B->C.

Perhaps someone who knows a tad more about engineering than I do (e.g. stilson ... :) ) could give an opinion about this idea?
 
Last edited:
Ratbag said:
The process is the same as trying to twist something with your hands held close together, or with your hands held further apart.
Click to expand...

Thats the problem with lift blocks, they exaggerate the forces applied to them. A few members have had trouble with their trailing blocks cos of this. Thats why I tied my trailing arm/moustache bar blocks together, also my front control arm blocks. Now I wont have a "twisting" force on them as they rock back & forth, just a "shear" force. Thats the idea anyway... :iconwink:
 
Ratbag said:
Gidday Folks

It occurred to me that weight in the vehicle, or more specially hanging off the back bumper area, puts greater torque on a lifted vehicle than it does on the same vehicle with no lift.
Click to expand...

Not sure about this. My thinking is;

If we are talking only about the torque applied by the weight of the load acting vertically downwards then the torque on the strut would be the same.
Torque is defined as force applied by perpendicular distance (in our case horizontal) from the point at which the torque is being measured. So for lifted and non lifted vehicles the horizontal distance is the same and therefore the torque is the same.

However if you consider loading cases such as braking and accelerating or climbing or descending then the force will no longer be vertical and therefore the lift will result in an increased torque.

I could be completely wrong though as im half asleep at the minute so the brain probably isnt working..... maybe ill have another think in the morning
 
Gidday DW

DedmanWalking said:
Not sure about this. My thinking is;

. . .

I could be completely wrong though as im half asleep at the minute so the brain probably isnt working..... maybe ill have another think in the morning
Click to expand...

I know that feeling only too well, mate ...

I really need to draw a mud map of what I am thinking, but far too buggered tonight!
 
DedmanWalking said:
However if you consider loading cases such as braking and accelerating or climbing or descending then the force will no longer be vertical and therefore the lift will result in an increased torque.
Click to expand...

Thats spot on. Its the horizontal forces that are acting on the lift blocks that cause the increase in torque on the bolts/captive nuts. Not so much acceleration, lol, at least not in my Foz :( more braking, cornering & esp hitting potholes, ruts, rocks, etc while climbing a steep track. Thats what I was/am concerned most about.
 
The regulations don't stop anyone from making a very capable off-roading Subaru. To be honest i think if you start going extreme with mods to a car that wasn't designed for the purpose in the first place then you just end up with a cascading effect of other problems, e.g. stresses on captive nuts, clearance issues, poor gearing etc. People seem to get a bit obsessive about the biggest tyres and lift, when all the best Subaru's I've seen off-road have a mild lift, roughly 27" tyres and at least one decent LSD. Big tyres and lift might work for a 4WD but i think it makes a Subaru less capable if anything. I think the regulations are about spot on.

I personally consider it more of a challenge to build my car to be capable and legal.
 
Last edited:
Venom said:
The regulations don't stop anyone from making a very capable off-roading Subaru.
Click to expand...

Yep its amazing what you can do with a legal Subaru :lol:

Venom said:
People seem to get a bit obsessive about the biggest tyres and lift, when all the best Subaru's I've seen off-road have a mild lift, roughly 27" tyres and at least one decent LSD
Click to expand...

Have always thought that going crazy with the tyres is just going to cripple your low range and cripple your off-road ability. Also one of the advantages of a subaru is that it can go places other 4WDs cant due to it low centre of gravity, to much lift and you remove this advantage.

One day i will engineer a rear locking diff and the the foz will be unstoppable.

Venom said:
I personally consider it more of a challenge to build my car to be capable and legal.
Click to expand...

Very true, but sometimes its just a pain in the neck.......
 
I can certainly see where you guys come from.
I'd be one of those people with an extreme lift and mild tyres.(225/70r15).
The lift looks awesome, the vehicle is highand never has clearance issues but it doesn't drive like how it used to onroad. Although it rides, drives and corners much better than the majority of 4wds. ..
I was actually considering decreasing my amount of lift by an inch or so. 115mm in the rear end is a little too extreme. ..
 
I just checked the NSW RMS website for the light vehicle modifications session as below, for my understanding is allowed to raise up your vehicle no more than 1/3 of original ride height; for example, my Forester has 225mm ground clearance from the factory which means I can lift my vehicle up to 225/3 = 75mm will be fine and legal, please correct me if I am wrong.

SUSPENSION
Item Modification
12 Altering vehicle ride height by more than one third of the manufacturer’s suspension
travel in the direction of the ride height change.
Examples requiring certification:
• Conversion from coil to leaf springs.
• Any modification to the suspension configuration.
• Fitting a suspension of a different design eg from a different make and model
(eg from coil springs to leaf springs).
• Fabrication of suspension mounting points.
Examples not requiring certification:
• Modification of suspension with components or parts which meet or exceed the
original vehicle manufacturer’s specifications.
• Fitting uprated roll (sway) bars, shock absorbers, springs, struts or manufacturer’s
options for that particular year make and model.
 
It's one third of "suspension travel" not one third of ride height.
 
Back
Top