Tyre Size Calculator

Tyre size for rim size/width calculator tells you what tyre sizes to go for, for the size of your rim. For .eg., it gives an answer to the question:”I’m going for 6.5 x 15j rims. What’s the best tyre size?” Also, it shows tyre width range for the selected rim: minimum, ideal and maximum tyre widths.

Why is the diameter so important?

It is because speedometers, traction control, torque and the gear settings of a car are based on how far the tyre travels in a full revolution. This is linked to the outside diameter.

If the size is too different this affects the time/length it takes for a full tyre revolution (the tyre rolling circumference), which will cause your speedometer to display incorrect readings and your gearing will be adversely affected.

Keeping the Same Diameter

To keep the same overall diameter, you need to make adjustments. If, for example, you were to move up a rim size from 16” to 17”, you will need to choose a tyre with an inch less in the standing height of the tyre.

Understanding Tyre Size Maths

This is where it gets a bit more complicated. The aspect height of a tyre is shown in the tyre size as a percentage of the width – the aspect ratio.

Let’s take the tyre size 205/55/16 for example. 205 is the width of the tyre in millimetres – fairly straight forward. However, the 55 is the ratio of the tyre’s width to the tyre’s height.
So it means that the aspect ratio is 55% of the 205mm width. In this instance that is 112.75mm.
At this point you will need to convert the size from millimetres to inches – there are 25.4 mm in every inch.

Please do not fit a different sized tyre without first consulting an expert at Autocraze

Autocraze will be able to tell you if you are trying to fit a tyre with a tyre size that could lead to an accident or damage to your car.
If you are interested in finding out more, call our team of experts on 1800 099 634 and they will be happy to discuss the matter.


Maths Summary:

Multiply a tyre’s width by the aspect ratio to get aspect height (205 x 0.55 = 112.75)
Convert into inches (112.75 / 25.4 = 4.44)
Double the aspect height (4.44 x 2 = 8.88)
Add inside diameter of tyre (8.88 + 16 = 24.88)
When changing tyre size, the tyres should not have more than a 1% difference in diameter – less than 0.5% would be ideal.

Why buy Tyres at AutoCraze! 

► All our Tyres for sale are load rated at AutoCraze
► All Tyres comply with Australian standards
► Free shipping Australia-wide* on all Tyres
► Buy now pay later – 12 Months Interest Free on all Tyres
► Free fitting and balancing for all wheels and tyre packages
► Free installation kit for all wheels and tyre packages*
► 100% fitment guarantee on all wheels and tyre packages

Pricing & Packages

Tyre Packages start at a low price of $147.00 all the way up to $2000.00 depending on wheel and tyre brand combinations. | Sizes  15″ 16″ 17″ 18″ 19″ 20″ 22″

Tyres are able to be upgraded to many levels based on personal needs and requirements, this will create a varied outcome on the price of each package.

How you can buy Tyres from Autocraze

Available ONLINE at via direct links on our Twitter & Facebook pages | Alternatively give us a call on 1800 099634

AutoCraze are your wheels and tyre specialist with in-house expert advice. Offering not just wheels, and tyres but also a wide range of high quality 4×4 suspension from big brands at AutoCraze. If that wasn’t enough we even accessories. With over 30 years of combined experience in the automotive industry. AutoCraze will be able to cater towards your needs in one convenient location.

AutoCraze ships hundreds of wheels weekly Australia-wide!