Rim/Wheel size guide for beginners

It is common knowledge that not all type of wheels will fit all cars. But with our wheel guide, users will be able to understand different parameters of wheels such as wheel offset, width, diameter, and rim size among many other things. All you have to do is to click on your car model from the list!

Wheel size basics

The first thing that users need to know is the fact that the wheels they chose must be compatible with the tire selection and car model.

Wheel dimension

The different parameters of a wheel include: width, diameters, offset, and bolt pattern. Let's have a look at the different wheel parameters. To make it more descriptive, we will use the example of 16x7 4-100 40S to explain the different wheel specs.

Wheel’s diameter

The denotation 16 reflects the wheel diameter. Wheel diameter translates to the distance between the face of the wheel.

Wheel’s width

7 is the wheel width given in inches. It translates to the distance between the beads all the way to the barrel of the wheel. For example, 6.5x15 means that 15 is the diameter and 6.5 is the wheel width

Wheel bolt pattern

4-100 translates to the bolt pattern. The 4 labeling stands for the number of lug holes contained in the wheel while 100 shows the distance between one hole and the other. One important thing to note is that it is always a requirement that bolt pattern of the wheel must match bolt pattern in your car.

Wheel Offset

From our example above, 40 will be the wheel offset which is always given in millimeters. Wheel offsets tend to come as zero, negative, or positive.

Centre bore

The center bore is the size of the center hole found in the middle of the wheel that is given in mm.

Strategies of finding out what is your rim size

All you have to do is to locate the tire size embedded on the sidewall of your car. It will always look something like this - 245/35ZR-20. Your rim diameter will be 20.

Understanding what the wheel size means

If you find the letter “P” as the first letter of your tire size, then it means that your tire is a P-Metric tire which meets standards to be used in the US.

If it has no letters whatsoever, then you are dealing with a Euro-metric type of tire.

Tire width

For a P215/65 R15 tire, the tire width will be 215 millimeters.


For a P215/65 R15 tire the aspect ratio will be 65 indicating that the tire’s height is equal to approximately 65% of the width.


For a P215/65 R15 tire, the R labeling will mean that the tire is Radial indicating the fact that the layers in the tire run radially across the given tire.

Wheel diameter

For a P215/65 R15 tire, the wheel diameter would be 15.

Load Index

Load index indicates the maximum capacity that the given tire can support when fully inflated

Speed rating

The sped raring indicates the maximum sped that the tire can comfortably handle. For example, an H-speed rating means that tire maximum speed is 210km/h.