Are 35 inch tyres legal? How can you check?
Fitting bigger tyres to a 4WD has been a common practice for years and years gone by, and it has a number of benefits. On the flip side, there’s also a number of downsides that often aren’t considered.
However, for the purpose of this post, we’re looking at whether 35 inch tyres are legal.
This question is actually really easily answered, and comes down to two factors:
What is the maximum tyre size on your year model?
When you open the drivers side door, you’ll see a sticker on the pillar on the left hand side that has all of the information you need to know about 4WD tyres.
It will list your vehicles tyre size, and normally a couple of different options. Write down the tyre sizes, and then look them up to see their diameter.
Using a basic tyre size calculator, you can convert it into metric or imperial, depending on which way you want to go. Now, its important to know that some models within a range of vehicles come out with larger tyres.
The LSU Dmax for example came out with 11mm bigger tyres than the SX and LSM versions, despite being an identical vehicle (except for cosmetic changes).
The increase of tyre size that you can go is based around the factory tyre sizes, and the larger the tyre, the easier it is to go up a size.
What are the limitations of your local road authority?
The next thing to find out is what the regulations are in your area. In Western Australia we look at VSB 14, which states a maximum increase of 50mm in tyre size, in conjunction with a maximum roof height increase of 50mm by way of tyres, body lift or suspension lift.
This essentially means you can go up 50mm in tyre diameter (which lifts your vehicle 25mm) and then lift your car 25mm, but you can’t do 50mm on both without 4WD engineering.
Some states allow 50mm tyre size increase and a 50mm lift, and you need to consider both before you fit bigger tyres.
Want to know more? Check out is your 4WD legal?
If the OEM tyre size is within 50mm of a 35 inch tyre, then you should be able to legally run 35 inch tyres. Most 4WD’s come out with 31 inch tyres, and occasionally 33 inch tyres so running 35’s legally is not often simple.
Be aware that you often cannot just fit 35 inch tyres; you’ll often have to do body mount chops, or a suspension or body lift, or even adjust the position of the front differential to make them fit, and this in combination with the tyre size increase can also make it illegal without engineering.
One little ‘loophole’ is that if your vehicle is registered at over 4500kg GVM you fall under light truck laws, which are a whole new kettle of fish and allow you to run some huge lifts and tyres completely legally.
Generally this is restricted to larger vehicles (like the American trucks, and actual trucks), but its still a good option!
Seek engineering
If you still want to run 35 inch tyres and you don’t meet the above criteria, you can go down the path of engineering.
This involves getting an automotive engineer to review your 4WD and sign off that it is safe to drive on Australian roads.
In WA, this usually involves lane change testing, or swerve testing where your vehicle is driven at speed on a private race circuit and weaved in and out of cones at speed. If your vehicle handles badly, or rolls over, you fail the test!
Do you actually need 35 inch tyres?
Off road, clearance is always good, and its incredible how much difference a bit of extra height will make.
Your tyres are really the only thing that picks the entire vehicle up, which is why tyre clearance is so valuable.
You can do a suspension or body lift, but you still end up with your differentials being the lowest point, and that’s a problem.
Only you can really answer whether you need 35’s or not, but I would take a twin locked 4WD on 33’s than an unlocked one on 35’s any day of the week.
Also, make sure you understand the downsides of fitting 35’s, as the list is extensive and it will cost you to have them fitted in a number of different ways.
