Modify tyres and suspension legally Part 2

Modify tyres and suspension legally

In a previous post, I discussed my experience when trying to modify tyres and suspension legally to raise the height of my car by less than 50mm… As you’ll read, I didn’t have much joy.

It’s important to make sure you do keep within the legal boundaries of modifications. If you don’t then you may end up with a yellow sticker, but also your insurance company may have a way out of making payments should anything terrible happen. Although you may find some insurance companies say that they’ll insure your 4×4 modifications, call them up and ask them if they’ll insure something that’s effectively illegal. I’m sure you already know what the answer will be.

My vehicle is fitted with Electronic Stability Control. Most cars have it now days but it may be called something slightly different (perhaps Active Stability Control or ASC). So this post and the previous one focus on modifying the height of a vehicle that is fitted with this technology.

So lets get to it…

VSB14 and the NCOP

VSB stands for Vehicle Standards Bulletin. It’s basically a design guide to make sure all vehicles in Australia comply to a bunch of safety regulations. These regulations are outlined in NCOPs.

NCOP is the National Code of Practice. Each NCOP relates to a particular item.

We’re interested in VSB14 and NCOP11 – Section LS Suspension and Steering V2.1 last edited on 15 November 2015.

Since my last post there have been some changes that relate to vehicles fitted with ASC. The previous version of this document basically said that if your vehicle has ASC, then to raise the height of your vehicle in any way, you’d need to ensure that there is no impact on the ASC by one of the below methods:

  • Get vehicle manufacturer signoff – Never going to happen… Trust me. I tried…
  • Modify the ASC code to allow for the change – Yeah right…
  • Prove it through testing – You can read my previous post to see how much luck I had there.

Now, however, the NCOP clearly states what you need to comply with, and what you need to do if you don’t. And there are 3 different stages. Well 4, if you count lowering your car… Note that raising your vehicle height includes all methods of raising the height. So it’s a total height increase taking into account suspension, body lifts, tyre diameter, spacers… everything.

Raising your car by more than 150mm

The short of it is “Don’t do it”. It’s not legal in any way.

Raising your car by more than 50mm but no more than 150mm

You can do this, but you need to pass a lane change test.

Raising your car by 50mm or less

You can do this without any kind of certification. It’s legal. Go ahead and do it. Have fun. Enjoy the ride.

Lowering your car by any amount

Go for it, but you have to comply with other things. But who really wants to lower their 4×4 anyway?

Now this is my interpretation of the rules so please read the NCOP and make your own judgement. Don’t just trust the stuff you read on some random page on the Internet…

15 Replies to “Modify tyres and suspension legally Part 2”

  1. Hi,

    Thanks for the update.

    Quick question – I was reading the amendment and it states you can go up to a 50mm suspension lift without needing certification, but if you want to do a 50mm + tyres or anything like that you need certification.

    In regards to the tires, do you know if you’re able to upgrade the tires as it use to say this is not allowed due to the effect on VSC? (Without doing the 50mm suspension lift)



    1. Hi Alex
      Yes by my interpretation of it, you’re correct. If you want to do anything at all that raises your vehicle by more than 50mm but less than 150mm then you need to pass a lane change test. So if you put on a 50mm suspension lift and then also get larger tyres you need to get it certified.

      My understanding is that you can increase the rolling diameter of your tyres without doing a suspension lift just fine. However having said that, there is a whole section in there about tyre size changes that I haven’t touched on at all… Hmmmm… Might have to…

      1. Awesome thanks for that mate.

        Yeah finding it a bit hard to follow lol. Some tyre shops say you’re not allowed to put bigger tyres/wheels on as you have VSC, some say yep no problem.

        1. Wow! I’m surprised that tyre shops say that! Most people I’ve dealt with just sell it to you anyway and the legalities are your own responsibility…

          I had a brief read of the regulations and there are some tyre rolling diameter and profile rules, but I haven’t dug right into them to try to understand them yet.

          1. Yeah I was really surprised, I actually called a couple of different ones (The same chain) and they both told me the same thing. And that they also had the same issues putting tyres on their own work vehicles.

            Yeah I had a look at those as well, but I couldn’t see anywhere whether it stated it applied to vehicles with VSC/ESC or not.

          2. Yeah I just had a good look and it gave me a headache…

            The bits that are relevant seem to be sections 4.2.4 and 4.2.10.

            4.2.4 SEEMS to say that a 4wd can increase the overall rolling diameter by up to 50mm. But it’s very confusing and badly worded if you ask me so read it and form your own opinion… I.e. don’t blame me 🙂

            4.2.10 talks about the maximum width you can go to and SEEMS to say that you can increase the width of your tyre but no more than 50% of the original tyre from the factory. Which seems like a lot but there you go… Once again don’t blame me 🙂

            BUT, you can only do all this while staying within guidelines around raising your vehicle height as outlined above…

            They also don’t seem to want you to decrease your wheel track at all (section 4.2.11 and also section 4.11)

        2. What you are saying is scary but true. I work in industry for a major chain. The store I am at used to say “as per placard” or not at all. Having said that, a few guts used yo come in and get muddies and rims for their “boat trailer”. Other shps simply shove on whatever will fit under the guards. I have read all of vsb14 back to front so many times it hurts, as i feel i have a legal AND moral responsibility to do it right. Some reputable looking shops either dont understand or care about something so simple yet crucial as load ratings

          1. Good on you mate. There should be more like you. You’ll lose business because some people just want their massive lifts and huge tyres regardless. But you’ll know you’re doing the right thing so thumbs up to you!

  2. You’re not alone there lol, they don’t make it easy.

    Ok awesome, yeah of course.

    Thanks for having a read into that mate, appreciate the help.

    I guess it’s a step in the right direction either way though!

    Next step: Making it a lot easier to read lol.

  3. Very new to this blog and interesting and informative discussions.
    Thank you to All,
    I am a little disappointed with the advice I was given when I wanted to raise my Prado. Advice by a very reputable company was that I can legally only raise it by 50 mm (2 inch Old Man Emu Lift). i wanted to and prepared to pay for a maximum lift no matter what the cost was. (small man syndrome)

    1. You should look up the rules in your state, but in WA there are 3 categories. A lift you can do without approval, a lift you can do but you’ll have to pass a lane change test, and lifts that are just illegal and won’t ever be approved.

  4. You need to clarify the rules a bit better. The limit on vehicle height change only applies to suspension and body lifts, NOT tyres. So if you put the suspension on first (without changing tyres) you can go the full 50mm. As there is not height change limit for tyres, you can then put on larger tyres without having to worry about height changes.
    Also note that the 50mm limit is above the standard height of your vehicle. If you have added accessories like bull bars, roof racks, extra batteries, etc, etc, you will be sitting below the standard height of the vehicle. So you can lift if more than 50mm.
    Vehicle manufacturers often specify the ride height as a range. So you can go 50mm above the maximum figure specified by the manufacturer.

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