If you own a car, learning how to measure rims offset is crucial.
The measurement helps you establish the distance between the wheel mounting surface and the rim centerline.
With this measurement at hand, you can easily maintain the same difference between the tires in your car axle as the original when replacing the rims.
In the long haul, this will help you avoid wheel bearing fatigue and steering difficulties.
If you fall into the category of folks who don’t know how to measure the wheels offset, this post is for you.
Below, you’ll discover an easy and quick guide for measuring rims offset of your tires.
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1. I’m assuming that the tire is still mounted on the rim, so start by laying down your rim on a flat surface. Place a straight edge, e.g., a piece of straight metal or wood, across the rim top. Note the measurements from the ground, all the way up through the rim spokes to the straight edge you’ve placed at the top.
If possible, try deducting the tires overhang on the edge of the rim on both sides. This ensures even more accurate results.
For those who are dealing with the rim alone (with no tire mounted), simple measure its width from one side to the other and note the measurements down. (This is a more accurate method).
2. Take the measurement you’ve obtained above and divide it by two. This will give you the rim centerline measurements, which we’ll use later in this guide.
3. Now lay your wheel down (face flat) on a flat surface to take the next measurement. Use your tape measure to obtain the distance from the hub mounting surface all the way to the rim’s rear edge.
The measurement you’ll obtain is known as backspace. Note it down as well.
4. In the next and last step, you’ll need to take your backspace measurement and subtract the centerline measurement. The answer you’ll get is simply your rim offset!
Getting rim offset is that easy!
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NOTE: In the fourth step, you might get a negative value or a positive value or even zero. In other words, you can get a positive offset, a negative offset, or a zero offset.
This is what each of these values means:
- Positive offset: occurs when hub mounting surface falls toward the rim’s centerline front or wheel side. It usually occurs in the newer or front wheel drive cars.
- Negative offset: results from the hub mounting surface falling toward the rim’s centerline back or brake side. Negative offset is usually associated with “deep lip.”
- Zero offset: in zero offset case, the hub mounting surface lies even with rim centerline.
You don’t need to be a pro mechanic to learn how to measure rims offset. You don’t need to attend a class to learn that either. Just follow our simplified steps above, and you’ll easily find the offset value of your wheels.
Remember that offset helps you avoid cases of wobbling legs or steering difficulties whenever you make a rim replacement.