Thread: Legal body and wheel modifications

Your best speaking to your local road transport authority as what others have done in different states is irrelevant. My Disco is registered engineered in Tas with 3" lift and 33" tyres, but that means jack for you in Queensland.

Originally Posted by Mick_Marsh

The ADRs are "Australian Design Rules".
The VSIs are national too. VSBs as well.

The problems occur when the person in authority enforces decisions based on their own uninformed personal opinion (as opposed to informed professional opinion). For example, that now famous vehicle inspector at Regency Park who wanted the Perentie owner to remove the brush bar because, in her opinion, it "looked aggressive".

The height for lift and tyre sizes are in legislation somewhere. It's just a matter of finding that legislation.

Road rules, now that is a different matter. Personally, I find it a miracle we're all driving on the same side of the road.

no.
the ADR's are a recommendation. it';s up to each state to put it into state legislation, and they often change it before they do.

it's really quite stupid

I was under the impression that body lifts on vehicles with Air bags were not allowed.

Originally Posted by crash

I was under the impression that body lifts on vehicles with Air bags were not allowed.

Most of the lift conversions on a D2 replace the air bags with springs

many maybe,, but certainly nowhere near all,

Originally Posted by bgkdavis

I've just bought a 2" body lift kit for my disco 2 and have just found that there may be some confusion over the legal issues, unfortunately I've done a search on this forum for topics on this issue (and there are many) only to find the same confusion, and the matter isn't helped too much by there having been apparent changed in the laws.

My plan of installing 33" tyres and a 50mm body lift is definately not legal without engineer cert.

How hard is it to get a lift modification certified?

OK, to be more helpful and answer the final question, if the inspector is doing the job right they should look at these for the body lift:
* Steering wheel collapsible column issues (if you extend it then what material, has it compromised the safety? if not extended does the airbag now no longer operate as intended)
* length of brake lines, especially any hard links from body to chassis
* length of ABS lines
* any body to chassis electrical looms
* any body to engine loom links
* any body to engine loom pipes (coolant, fuel, oil etc.)
* body line issues by the new gap, I guess particularly at the front where you may now have gaps that are considered too sharp
* gearbox operation (especially if manual)
* headlight alignment (especially if you have a bullbar, since they may now foul the beam - which would mean changes to headlight mounting?)
* any items that connect to both body and chassis (radiator - connects to chassis, body and engine, can't think of anything else off hand)
* reinforcing on body mount areas to account for extended length leverage issues?
* verification of anything like accelerometers being re-calibrated (if you have ACE I guess the CofG may be used in calculations, so changing the moment of the measurement will affect the calculations, so I'd probably like to see the SLABS reprogrammed or verified that the position of the accelerometers isn't used) as needed
* any internal signage (i.e. sunvisor heights) modified to reflect the new dimensions
* are wheels still covered at least 75% (?) of circumference

That's quite an annoying list isn't it?

For a suspension lift I'd expect:
* testing on full droop (both and either side) for binding of propshafts and any contact of suspension to chassis or body, spring remains seated, pinching, propshaft overextension, steering joints for binding
* testing on full compression for contacting, also if the shock bottoms out, unless it has an in built bump stop (I think pro-comp did?), pinching, basically same as droop
* testing of castor angle and resetting to manufacturers +- specs
* brake and abs lines sufficient length (on droop test)
* excessive compression or extension of suspension bushings
* recalculated CofG and hence max side angle and climb angle - but no idea of what would be an unacceptable value, it's likely to be less than original, but what is too much?
* physics simulation/calculation of lane change response with full load - followed by actual test (you can't just do the test, what happens if it fails and the tester dies?)
* calculation of any new tare/tow mass changes
* headlight aiming

For the tyre/wheel change I'd expect:
* checking wheel body protrusion (wheel arch flares)
* checking for coverage (mud flaps)
* fouling of body/chassis/suspension
* changes to CofG calcs and all the rest as for a lift
* speed correction (to all ECUs that use it for safety features, i.e. SLABS and not just the dash display)
* recalculation of wheel bearing loads for acceptable stress and heat
* recalculation of braking forces (though thinking about this, I reckon the weight of the care probably makes heaps more difference than an extra couple of inches on tyre size)
* brake testing
* lane change crap


How much of this would your state do? For tyre and suspension lift - probably a dude with a flash light will have a scan of the underneath, wiggle a few things and suck through his teeth. Then take it for a few runs of braking and lane changing hoping he doesn't roll it. Depending on if he got laid this week and what's for dinner he sign off on it and you get to go on your way - he can always claim you changed stuff later or didn't maintain it so you can't claim on his professional and product liability insurance.
I reckon the body lift would be a lot more difficult to get past, there is a lot to change correctly, it depends on what they understand about the vehicle and for this reason the mechanic might be reluctant to sign off on it.
The older vehicles are far simpler for body lifts from the electronic point of view, the main issue being steering column extension IIRC.

This is all the view of an actual engineer though The inspector and mechanic will likely be less thorough :-p

Originally Posted by trout1105

Most of the lift conversions on a D2 replace the air bags with springs

I believe he means safety air bags such as SRS not suspension spring type airbags like SLS. He is correct in that many states do not allow body lifts on SRS airbag fitted vehicles.

Originally Posted by twr7cx

I believe he means safety air bags such as SRS not suspension spring type airbags like SLS. He is correct in that many states do not allow body lifts on SRS airbag fitted vehicles.

OK, No Worries.
Air bags on 4X4's have been around for a long time now and Many of these types of trucks have lifts So they are all illegal or there is a way to get them done legally.
I was under the understanding that 50mm was the magic number.