Offset Explained
Selecting the right fitment is important to on-road performance and off-road capability, especially for 4x4s exposed to the unique stresses of Australian roads and government regulation. Wheel offset is the distance between the wheel’s mounting face and the centre of the wheel. It determines how far in or out your wheels sit relative to the vehicle’s body and suspension. There are two main categories that a wheel offset can fall into, negative offset, and positive offset.
Negative Offset
Depending on the vehicle a negative offset can cause the mounting face to sit behind the centre of the wheel, creating a wide, aggressive look, that really pushes the wheel out. The result is a ‘poked out’ look you often see on modified 4-wheel drives and off-road vehicles. Negative offset wheels are typically, a more “deep-dish” look or are more concave in design, due to the negative offset. Going negative can improve stability on rough terrain by widening your vehicle’s track; however, it can put extra stress on studs and bearings, as well as potentially causing scrubbing if you don’t have the right setup. Negative offsets are often found with older vehicles, such as the GU/GQ Patrol, and 80 Series Land Cruiser, or run on new vehicles wanting an extremely aggressive set up.
Positive Offset
A positive offset does the opposite, it’s the tucked in conservative look. With a positive offset the mounting face sits in front of the centre of the wheel, which pulls the wheel inward, tucking it in closer to the vehicle’s body. Positive offset can cause a flatter wheel style with less “deep-dish” effect compared to the wheels with lower or negative offset, due to where the mounting face must sit. A positive offset is more common on newer vehicles, like the 300 Series Land Cruiser, and Ford Ranger which have high offset wheels from factory.
How to Measure Wheel Offset
To get the centreline, measure across the width of the wheel and find the middle point. From this position, the mounting surface shows where the wheel sits on the hub.
The distance between these two points if the wheel offset, and it is generally measured in millimetres. It is important to remember that wheel width is measured between the bead seats, not the outer edges. If measured by hand, figures may differ slightly from the standard measurements because wheel width is measured differently. If your hub surface is further out than the centreline, it’s positive. If it’s further in, it’s negative. Below is a video explaining this.
Legal Considerations and Regional Advice
Before modifying your vehicle, we always recommend doing your homework prior to making changes to your factory offset and wheel sizing, as local laws in Australia can vary between states. Aside from the legal ramifications, it’s important to consider the safety of your car, as by putting an offset that is higher than your factory fitment you can cause what’s called under tracking, which is both illegal and can create poor stability. On the flip side, running a very aggressive negative offset can push your wheels out beyond your guards, which is also illegal and can increase the chance of fouling. The best thing you can do is talk to your local ROH dealer roh.com.au/where-to-buy/, as they will be able guide you on what’s best suitable for your specific vehicle and setup.
Why Use ROH Wheels?
ROH Wheels are offered in a range of fitments to suit everything from a simple set up to a highly modified 4×4. Built for tough Australian conditions, ROH Wheels provide high load ratings, durable build quality, and designs that feature genuine bead-locks for those who desire extreme performance.
It is important to understand these wheel offsets when choosing wheels for your vehicle, as they can significantly impact handling and performance.
If you’re ready to upgrade your wheels check out our range of off-road and street wheels, produced in a range of designs and fitments to transform your vehicle setup.