Your vehicle wheels have two key measurements: offset and backspacing. Offset is the distance from the wheel's hub mounting surface to the centerline of the wheel. Backspacing is the distance from the back edge of the wheel to the hub mounting surface.
Both offset and backspace are measured in inches. To measure offset, you will need a tape measure, a straight edge, and a calculator. Measuring backspace is a bit more difficult and will require a measuring tape, a ruler or yardstick, and some basic math skills. So, let`s get started!
Is Backspacing Same As Offset?
The truth is, wheel offset and backspacing are two ways to measure how your wheels fit your ride. Wheel offset is the distance from the centerline of the wheel to the mounting surface. Backspacing, on the other hand, is simply measuring from alternatively, you can think of backspace as measuring from the wheel's back lip to where it will be mounted. Thus, the backspace will be different based on the width of the wheel.
At the same time, they correlate with each other in such a way that a change in one will result in a corresponding change in the other.
How To Measure Wheel Offset?
Wheel offset is measured in millimeters and is the distance from the wheel's hub mounting surface to the centerline of the wheel. To measure offset, you will need a tape measure and a straight edge.
- Position the wheel/tire assembly on a flat surface and lay a straight edge diagonally across the tire.
- Use a measuring tape to get the distance from the floor to the straight edge, then divide that number by two.
- To find the center of the room, measure the distance from the floor to the ceiling and divide it in half.
- Next, measure the distance from the straight edge to the wall. To get the offset, subtract half of the room's width from the distance between the straight edge and the wall. The resulting number is your wheel offset!
New wheels shouldn't have an offset that is more than 5 millimeters different from the old ones. So, the standard wheel offset is between 38 and 42 millimeters.
How To Measure Backspacing?
This parameter is a bit more difficult to measure and will require a measuring tape, a ruler or yardstick, and some basic math skills.
To measure backspace, position the wheel/tire assembly on a flat surface and lay a ruler or yardstick across the tire parallel to the ground. Use a measuring tape to get the distance from the ground to the edge of the wheel.
Next, measure the distance from the ground to the point where the ruler or yardstick intersects with the tire. The difference between these two numbers is your backspace! To calculate it, just subtract the second number from the first one. And that's it!
The average aftermarket off-road wheel has between 3.5 and 5 inches of backspacing. A wheel with more backspacing will appear sleeker since it tucks under the fenders, whereas too little backspacing can affect steering negatively and lead to other handling issues.
Can You Calculate Backspacing When Knowing The Offset And Vice Versa?
Many drivers may wonder whether it is possible to calculate backspacing when knowing the offset (or vice versa). The answer is yes, but you will need a few more tools for that, namely a compass and a calculator.
If you already know the wheel offset and desire to calculate its backspacing, follow the instructions. Simply take the offset and subtract half of the wheel's width. The resulting number is the backspace. On the other hand, if you know the backspacing and want to calculate the offset, just add half of the wheel's width to the backspace. And that's it!
So, there is no need to measure both parameters, it would be enough to know just one of them. Keep in mind, however, that the resulting number will be an estimation since we are working with rounded numbers here.
When changing your wheels, it is important to keep the same offset and backspacing measurements. Otherwise, you might experience some handling issues or even problems with tire clearance. That is why it is always a good idea to measure both parameters before buying new wheels for your car.
Other Important Hints On Wheel Offset and Backspacing
When drivers know the exact number of their wheel offset and backspacing, they can pick the right wheels for their car without any difficulties. However, there are still a few things you should know about these parameters.
The first thing to keep in mind is that your wheel's width and diameter will affect its offset and backspace. For example, a wider wheel will have more backspace than a narrower one of the same diameter. The same goes for wheel diameter – a bigger wheel will have less backspace than a smaller one of the same width.
It is also important to know that offset and backspace are not the only parameters that affect a wheel's fitment. Another important factor is the bolt pattern – the number of bolts on your car's hub and the distance between them. That is why it is always a good idea to consult your car's owner's manual before buying new wheels.
In conclusion, offset and backspace is two important parameters that determine how well a certain wheel will fit your car. If you know these numbers, picking the right set of wheels will be a breeze! Just make sure to take all other factors into account as well, such as bolt pattern and width/diameter. And don't forget to check your car's owner's manual for more information.
Now you know everything there is to know about wheel offset and backspacing. Measuring these parameters is not as difficult as it may seem at first. Just grab a tape measure and straight edge (for offset) or ruler/yardstick (for backspace), and you're good to go! And don't forget to take into account the average values for each parameter when choosing new wheels for your vehicle.