Measuring Rim/Wheel Width

The rim/wheel width plays a key role when replacing wheels or modifying your tire size. The wheel width and tire size must be compatible in order for the tire and wheel assembly to maintain the safety and handling requirements of the vehicle.

Wheel Width and Tire Size

It is very important to stay within the range of approved wheel width/tire size combinations. The tire size determines the range of wheel widths that are safe to use.

For example, tire size 245/45R-20 has a rim width range of 7.5" to 9". This means that this tire size would fit a wheel size of:

• 20 X 7.5
• 20 X 8
• 20 X 8.5
• 20 X 9

Although it may be possible to mount a tire to a wheel width that is not recommended, doing so can lead to tire failure, irregular tire wear, or poor vehicle performance and handling.

Wheel Width and Performance

The width of your wheel has an effect on how your vehicle performs. For example, if you were to increase the width of your original equipment wheel without changing the original equipment tire size, there is less flexibility in the tire sidewall, which allows for faster steering response. However, with a stiffer sidewall, the tires ability to absorb impacts and road turbulence is transferred to the vehicle and is felt by passengers. If you were to decrease the width of your wheel without changing the overall tire size, there is more flexibility in the tire's sidewall, which allows the tire to absorb impacts and provides for a smoother ride.