Tyre size and legalities....help please

[ginslinger]

Hi all, we are limited to a max 75mm lift overall, right? There are so many opinions out there and as a newbie I want to be legal straight up. So am i right in saying that a 31in tyre is an increase of almost 5 in over the original spec? And therefore illegal?
All correct info gratefully accepted as I want to know where I stand before getting involved in the make.
Thanks, Tony

[Mike57]

Tony

What vehicle do yo currently have? The size you can go to depends upon what you start with. Is it a GV?

Mike

[ginslinger]

Hi Mike, I do not have a vehicle yet....just want to check out what mods are allowed etc. It will be a hardtop of some sort. I'm a muso and need to be able to lock up my gear. I see plenty of sierras with 31s or bigger and want to know where the law stands on this. I'm not interested in an argument with my insurer when I need them most!

[Scythe]

Doing any significant vehicle modification, whilst trying to remain legal really isn't simple. I have been trying to do the same thing myself. Some modifications are acceptable but only within the limits of some other modifications.

http://www.victoriapolice4wdclub.org.au ... hicles.pdf

This it the best guide I have found. I don't know what you are driving but my interpretation of the answer to your question about tyre size (based on my reading of the attached guide) would be that the start point is no greater than 50mm (with caveats) larger in diameter than your original tyres. Therefore 5in increase would be illegal. Even the 75mm overall lift has a bunch of caveats that must be met if you want to stay legal.

Trying to do modifications and stay legal is a real minefield. I work on the belief that if you keep the vehicle balanced, and not too ostentatious, you can create a viable 4WD without attracting unwanted attention on the street. Based on some of the ill-considered and dangerous modifications I have witnessed, some control seems warranted, but trying to fully interpret all the requirements against such documents as the one attached isn't alway helpful either (IMHO).

Option for 15mm on the tyres with 60mm lift split between body and suspension (max 50mm on suspension with caveats) seems to be a fair bet for legal on most cars.

But the best advice I would offer is read the document yourself and make an informed decision of how you want to proceed. All opinions, (mine included) are just that, but I hope mine is at least somewhat considered.

Hope this helps

Scythe

[ginslinger]

Thanks for that. I'm not overly concerned about being pulled over, it's my insurance policy being void after a bingle. As I understand it, if the car is legal then insurance shouldn't be an issue. As I also understand it we are allowed a 75mm total increase in lift, so the regular 2in suspension lift only leaves a 2in increase in tyre diameter to raise it a further inch....this means 28in tyres max. I'm happy to be set straight by those with a better understanding of this subject!

[Mike57]

I think you also need to notify your insurance company of any modifications even if they are legal (which they need to be).