Understanding Wheel Offset, Backspacing and Width – Easy Guide | Truck Accessories Explained

Understanding wheel offset, backspacing and width can take some time, but in this easy guide we go over exactly what they are, how to measure them and show you some examples of different real world scenarios. Watch More – https://goo.gl/zYYvJF

Shop 4 Wheel Online’s huge wheel selection: https://goo.gl/9MB7A4


Hey guys, Ken here with 4 Wheel Online and welcome to Truck Accessories Explained. In this video we’ll be going over what wheel width, offset and backspacing are, as well as things to take into consideration when you’re switching from stock wheels.

So let’s start with Wheel Width. Although it is exactly what it sounds like, it can easily be measured incorrectly if you don’t know the right way.

Wheel Width is measured from bead lip to bead lip and is not the actual width of the wheel itself.

Now that we have that out of the way we can move on to the offset, which is related to backspacing but is a separate measurement.

So let’s draw a line down the middle of the wheel… Offset is the distance from the backside of the mounting surface, to the centerline of the wheel.

If the backside of the mounting surface is exactly in the middle, the wheel has zero offset… But move the mounting surface outward and you’ll have a positive offset. Do the same thing but move it inward and you’ve got negative offset.

Offset is measured in millimeters from the centerline. So this wheel has a -51mm offset, while this wheel has an offset of +45mm. You’ll sometimes see this stated as ET45 depending on the source of info for you wheel.

Now that we understand Offset, we can look at backspacing, which is the distance from the backside of the mounting surface to the inside lip of the wheel and is generally measured in inches.

Like I said earlier, wheel width, offset and backspacing are all related and important factors to ensure a proper wheel sizing for your vehicle. Let’s look at a few examples of how the three relate.

We took the stats of three 20 inch tall KMC XD128 Machete wheels for this example.

The first wheel is 9 inches wide. It has an offset of zero and a backspacing of 5. As we learned earlier, since the offset is zero the wheel is mounted directly in the center.

Now, if you just did the math in your head you’ll realize that half of 9 inches is 4.5 inches, so how can the backspacing be 5 inches?

Easy, the 9 inch wheel width does not include the lip, but the backspacing does.

Next we have another 9 inch wheel, but this one has an offset of +25.

We can see that with this wheel the mounting surface is pushed outward, therefore the backspacing is increased to 5.98 inches. So more of the wheel sits over the axle.

The final wheel is 10 inches wide, but this one has an offset of -24mm.

Being a wider wheel you might expect it to sit even farther back than the previous two wheels, however that is not the case. The negative offset means the mounting surface is pushed inward. This wheel has 4.56 inches of backspacing. So less of the wheel sits over the axle.

For our next two examples we’ll look at what happens to a hypothetical 20×10 wheel with a +100 offset and another with a -100 offset.

You can see on the -100 offset wheel just how little backspacing there is, and the exact opposite on the +100.

That’s why it is important to consider width, backspacing, and offset when looking for new wheels. It’s never fun to spend your hard earned money on a new set of wheels only to find out they rub when turned to full lock or that they won’t fit over your brakes.

Lastly, it should be noted that it’s ideal to keep the offset as close as possible to the stock wheel, as changing this can affect the geometry of the suspension and even cause extra stress on the different components. Be sure to take into account your modifications like lift kits when looking over different wheel options as well, since most are designed around certain specifications.

Now that you know what to look for when buying new wheels, be sure to check out 4 Wheel Online’s huge selection of wheels and tires right here *points to the left* And be sure to watch the rest of our Truck Accessories Explained videos that cover other important wheel topics. Until next time, I’m Ken with 4 Wheel Online.

3 thoughts on “Understanding Wheel Offset, Backspacing and Width – Easy Guide | Truck Accessories Explained

Get involved in the conversation!

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s