Thread: New Tyres for my TD5

This page has a good comparison tool.
http://www.exploroz.com/Vehicle/Tyres/SizeCalc.aspx

Cooper STT 245/75 R16s. They look the goods, filling out the guard quite nicely. They give a small lift. The tread pattern is very pleasing to the eye. They perform well in sand and the rough. They are hard to puncture, although I have staked two side walls in the last 7 or 8 years. Good mileage. Not too noisy. Pretty average in the wet.

The comments above about a maximum of 15 mm increase in diameter being permitted are, I believe, out of date. The new national standard, being adopted by all states, is for a 50 mm increase in diameter. (and a 50 mm suspension lift giving a total of 10 cm lift without requiring an engineering certificate).

The OEM Michelins were great road tyres, but useless in gravel and off road.

Originally Posted by Roberto

The comments above about a maximum of 15 mm increase in diameter being permitted are, I believe, out of date. The new national standard, being adopted by all states, is for a 50 mm increase in diameter. (and a 50 mm suspension lift giving a total of 10 cm lift without requiring an engineering certificate).

50mm increase in diameter gives you a 25mm lift.

It's worth noting that the National Standards require that fitting increased diameter tyres does not result in wheels touching any other component:

4.2.3 Clearance
No part of the wheel must touch any part of the body, chassis, steering, braking system or
suspension under any operating condition. To check this, the vehicle must be fully laden and
capable of negotiating raised obstacles that would normally be encountered whilst driving such
as speed humps and driveway entries. This test should be conducted from lock to lock without
any part of the rim or tyre contacting any other part of the vehicle. Test weight for passengers is
68kg plus 15kg per person for luggage where luggage space is provided.

The wheels must be contained within the bodywork, or mudguards (including flares) when the
wheels are in the straight ahead position.

Steering and/or suspension stops must not be modified to provide clearance for wheels.

4.2.4 Overall Nominal Diameter

The overall diameter of any tyre fitted to a passenger car or passenger car derivative must not
be more than 15mm larger or 26mm smaller than that of any tyre designated by the vehicle
manufacturer for that model.

The overall diameter of any tyre fitted to:

• 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;

• 4WD goods vehicles and their 2WD equivalents if the chassis and running gear are
essentially the same as the 4WD version (N ADR category); or

• any medium weight goods vehicle (NA2, NB ADR category).

Must not be more than 50mm larger or 26mm smaller than that of any tyre designated by the
vehicle manufacturer for that vehicle.

Note: Increases in tyre diameter are subject to compliance with all other requirements
specified under this clause (Clause 4.2 Non-Standard Tyres and Rims) and may
therefore be limited by other factors such as insufficient clearance.

Speedometer accuracy must be maintained for the selected tyre and rim combination to within
the degree of accuracy specified in ADR 18 where applicable. It is suggested that the degree of
accuracy is in accordance with the most recent version of ADR18.

You can fit bigger, but then they require testing, but I don't know what the maximum size is though, I think there is a maximum overall height change limited by a combination of tyres and suspension.

Cheers
Kev

Originally Posted by bigkevg

You can fit bigger, but then they require testing, but I don't know what the maximum size is though, I think there is a maximum overall height change limited by a combination of tyres and suspension.

Cheers
Kev

I know there are state variations, so you'd have to check depending on where you are. The states regulations are generally harmonised to the national standards, so any differences are usually the exception.

The section in the national standards covering 50mm-150mm lift in body height still stipulate a maximum lift of 25mm due to increase in wheel diameter. That translates to a maximum 50mm increase in diameter above the maximum wheel size fitted by the manufacturer.

The largest of the stock tyre is the 255/65R16 fitted to 16x8 rims. The overall diameter is 737.9mm. If my interpretation of the national regs is correct, the largest tyre you can legally fit to a D2 is 787.9mm or 31".

In WA I recently read a bulletin where any vehicle fitted with a 2" lift and tyres not exceeding 50mm increase did not require examination, even though the new rules state otherwise. This is to obviously save them time looking at things that are reasonably save modifications.
I spoke to a vehicle examiner and larger tyres can be fitted as can higher suspension, but the vehicle will then require a swerve test and examination to be passed.
There is a maximum height that cannot be exceeded(relative to each type of vehicle) and that is measured in total gain, tyres, lift etc.....

I didn't enquire as to the maximum tyre size as I am only looking at 33s anyway.

Actually LR automotive sells their 4" kit for 33" tyres and they get those legal, so there are options out there, just depends on how much effort you want to put in.

Cheers
Kev

Offtrack, off course you are right about the 50 mm increase in diam giving a 25 mm lift. Ride height is determined by the radius (which is half the diameter).

Originally Posted by bigkevg

In WA I recently read a bulletin where any vehicle fitted with a 2" lift and tyres not exceeding 50mm increase did not require examination, even though the new rules state otherwise. This is to obviously save them time looking at things that are reasonably save modifications.
I spoke to a vehicle examiner and larger tyres can be fitted as can higher suspension, but the vehicle will then require a swerve test and examination to be passed.
There is a maximum height that cannot be exceeded(relative to each type of vehicle) and that is measured in total gain, tyres, lift etc.....

I didn't enquire as to the maximum tyre size as I am only looking at 33s anyway.

Actually LR automotive sells their 4" kit for 33" tyres and they get those legal, so there are options out there, just depends on how much effort you want to put in.

Cheers
Kev

Hi Kev,

LR Automotive only say "make it possible to fit larger tyres" in relation to their 4" lift kit. I've checked all the pages on their site and while they tell you what mods are required to fit tyres larger than 31" there is no discussion regarding the legality of such tyres on the road.