A Guide to Understanding Wheel Dimensions

Next to buying a lift for your Jeep getting new wheels and tires is the most visually impactful change you can make to your ride. With that in mind we wanted to answer a question many new owners have. How do I know what wheel will fit?

Backspacing and Offset

One of the more recent questions was about wheel backspacing and offset. We were trying to buy aftermarket wheels that would fit our Jeep after installing a new lift. The MOPAR lift we had installed recommended a wheel with 3.75 to 4.5 inches of backspacing and a maximum width of 9 inches to clear all of the suspension. But what does that mean to you?

choosingdiagram

As you can see in the chart backspace is the distance from the mounting surface to the rear edge of the rim. The smaller this number the less rim material is wrapped around the brakes and suspension. It also means the “deeper” the wheel is. Those big wheels that have the lugs and centers sunk in have a very small backspace dimension

wheel-offset-diagram

Wheel offset is where the mounting surface is located in relation to the wheel centerline. It adds a somewhat confusing dimension to selecting wheels. We mention it because there are some manufacturers who will notate their measurements using a formula like 16×7 with a 3.5 backspacing and some that would say 16×7 with a 0 offset. These wheels are exactly the same. The centerline of the wheel is 3.5 inches from the rear of the rim or half the overall width of 7 inches. A 0 offset is the center of the rim as well. Note that based on the rim width the offset or backspacing you need may change.

Bolt Pattern and Rim Diameter

A stock Jeep comes with 17×8 inch rim, 6 inches of backspace, and a 5 x 5 lug pattern. What what? Yes, lug nut pattern and dimensions are important in any discussion about wheels. You can get the backspace correct, the offset correct, choose your perfect rim in the ideal size and not be able to use it. Why? It won’t bolt on to your wheel studs. The Jeep 5×5 means 5 lugs, 5 inches apart. Older Jeeps used a 5×4.5 which means, you guessed it, 5 lugs 4.5 inches apart. If you don’t know your lug nut pattern just check your manual or owners forum.

The MOPAR 2 inch lift we are using for this article has specifications for wheel dimensions that will fit without any clearance issues and are designed to perform like the OE wheels. The wheels must be at least 17-inch diameter, 8-9 inches wide, with a backspace ranging from 3.25 to 4.75 inches. What’s nice is it gives you a range to work in and makes it easier to find a wheel that not only looks good but will perform with the suspension proeprly.

Put it all together and order up!

Take these dimensions and because the world of the internet is so broad you can simply search for wheels that meet these criteria, spend all day looking at photos and order them without leaving your couch. Better yet you can buy them through a vendor like TireRack and have them delivered with tires mounted, balanced and with TPMS sensors installed to bolt right on your vehicle!

Hopefully, this helps you in your own search for new shoes for your vehicle.

Here is a pic of the finished package we described above.

JK

William Connor

As the Editor, William is responsible for all the good, the bad, the ugly and the indifferent that happens at 4WAAM. William brings a wide range of experience to this role. He also wields a freely shared opinion on just about everything., just ask him.