Thread: AT Tyre size on stock D2

At the moment I have 255/55/18 on the D2 and thinking of getting 16" AT Tyres and yes I am planning to get 16" wheels too from wreckers.

My question is, what is the max size of AT tyres I can put on stock D2? TIA.

Background:
In tyre sizing the second number is a %age factor of the width eg 255/55/R18 means the tyre is 255mm wide with a wall height 55% of that ie 255mm x 55% = 140.25mm. R=radial and 18=Wheel Rim Diameter in inches.
Therefore your tyre size is 2 x 140.25mm + 18" (yes it mixes unit of measurement) = 737.7mm dia

For comparison, my 265/55/R16 = 737.9mm dia (8" wide rims)

You ask a good question and one I'm keen to know the answer as well but I think it could be split into two.

1. What size can be fitted on 16" rims without rubbing the guards?

2. What size can be fitted legally without it effecting insurance?

For what its worth, I rang VIC Roads today on this subject and in Victoria to be legal the tyre diameter should not be larger than 15mm above the manufacturers specified tyre size (in your case this would equal 752.7mm) and not wider than 25mm. (in your case 280mm)

As for insurance, this is a case by case basis. AAMI surprisingly did not have a guidline and only asked that the tyre size be declared if its non standard, then they would assess the impact on the policy.

Its a question I have asked myself many times. Would an insurance company pay up in the event of a claim on a vehicle with non-legal diameter tyres?

This tyre size calculator may be useful to some. http://www.exploroz.com/Vehicle/Tyres/SizeCalc.aspx

Hope to hear some insightful answers here.