Wheel offset refers to the distance from the center line of the wheel to the hub mounting surface. This distance is typically measured in millimeters and results in a negative, positive or zero offset. A mechanic will often need to measure the offset of a wheel when changing tire sizes. This is crucial because an improper offset could result in contact between the tires and other parts of the vehicle. Here are a few tips on how to measure wheel offset.
How to Measure Wheel Offset
You vehicle can have different types of wheels, but it is important to know how to measure an offset wheel when necessary. This post highlights the importance of measuring wheel offset and how to measure it. It’s a simple step-by-step process that’s easy to follow.
How to Measure Offset
Sometimes, the offset is printed on the wheel. However, it’s often in digits that are either impossible to decode or difficult to read. However, don’t sweat, you can always measure offset on your own. Since it’s impossible to measure between the beads with the with the tire on the wheel, there’s an easier way to find offset by measuring from the tire sidewall.
- Lay the tire/wheel on a flat surface (such as on the floor) and use a straight edge, placed across the tire to measure the distance.
- Then measure the distance between the floor and the straight edge then divide the resulting figure by two. This will calculate the centerline of your wheel.
- Now measure the distance from the straight edge to the hub flange.
- Subtract the smaller number from the larger number to get the offset of the wheel.
- Offset is negative when the centerline number is larger than the hub measurement; if the figure is smaller, then offset is positive.
On most cars, changing offset by even 5mm is enough to notice a difference in how the car handles because it changes the scrub radius by the same amount. If the car’s OEM wheels have a positive offset, you’re safe to install wheels with even more positive offset. All you’ll need to do is to move the contact patch out of its original position using spacers. Doing so will keep the scrub radius the same. You just have to ensure your new wheel can fit inside the fender without rubbing anything.
However, if your new wheels have a negative offset, there’s no way to move the contact patch in toward the car’s center. The only way you can determine how much the new offset will impact the scrub radius is to put the car on an alignment track.
Even if you’re certain you’ve selected the right wheels, it’s important to entrust a technician to confirm that all things fit properly.
The whole point of knowing how to measure wheel offset is for the end user to determine how many mm the wheel will stick in or stick out from the mounting surface of the hub. It’s important to bear in mind that even a few millimeters can affect look/stance, ride quality, performance of your vehicle and even more importantly, how safe the setup is. For more information, our experts here at Element Wheels are here to help.