Skip to main content

Wheel Measurments

We are often asked about offset and backspace for custom wheels. How are they measured? What is the difference between them? Wheelsforless fitment experts have been answering those questions since 1991!  you may finf these definitions of terms that are used to indicate various wheel measurements helpful to understand when determining correct fitment, especially on a custom application.
Mounting Surface: The mounting surface of a wheel is the flat surface on the backside of the wheel that actually comes in contact with the hub or drum.

Backspace: Backspace is the measurement from the mounting surface of the wheel (point the wheel actually comes in contact with the hub) to the very back edge of the wheel. Therefore the smaller the backspace measurement, the more the wheel will stick outward.

Offset: Offset is the measurement from the exact center line of the wheel to the mounting surface of the wheel. Offset is negative if the mounting surface is back of the exact center. Offset is positive if the mounting surface is front of the exact center. Offset is zero if the mounting surface is also the exact center of the wheel.

Pitch Diameter: Also known as bolt circle, bolt pattern, or "pcd" (pitch circle diamter). This is the diameter of the circle of the lug holes. The measurement is made from the center of the lug holes. For example, if there are five lug holes you would draw a circle through the five lugs and the diameter of that circle is the pitch diameter. If there are 5 lugs and the picth diameter is 4.5 inches then the bolt pattern is expressed as 5/4.5.

X-Factor: This is the measurement from the mounting surface to the spoke of the wheel. This measurement is important for oversized brake calipers. Oversized brake calipers will extend past the mounting surface, therefore, the x-factor must be know to ensure clearance.

Below is a diagram showing these measurements:

Also notice from the diagram that the rim width is measured between the rim flanges where the tire actually sits. Many people are confused by this because a wheel that is measured 8" wide is actually 9" wide from outside to outside of the wheel flange.


Popular posts from this blog

What Type Of Lug Nut Should I Use?

Which style lug nuts should I use with my wheels?  Many people have bought a set of wheels at a local swap meet, from a friend, or even an online auction and need lug nuts to install on their newly purchased rims.  Or they want to replace their current lugs to freshen up the look of their wheels.  Choosing the proper lug nut is critical.  Also there are some wheel retailers that do not include the lug nuts with the wheels and sell them separately.  At Wheelsforless we include at no charge the proper lugs for the wheels. Different type wheels use different lug nut types, and using the wrong type lug means the wheels will not be fastened properly and cause damage to the wheel, vehicle, or even injury if the wheel comes off the vehicle.

First you will need to determine the proper lug nut seat type.  Nearly all wheels have one of three lug nut seat types which are cone seat, mag with washer seat, and ball seat.  Thankfully today's wheels rarely use the old  mag and washer seat.  When …

Wheelsforless Customer Service

We are often asked if there is any connection between Wheelsforless and the Canadian company Wheels For Less.  There is not.  Wheelsforless is located in Texas and is not affiliated with any other company.  We are the original online company, and have been selling online since 2000.  Hundreds of thousands of customers have bought online from us over the last 18 years, and we strive to offer the best customer service in the business.

When we receive an online order, that order is reviewed for correct fitment by our experienced tech department.  We often call our customers who have purchased online to talk with them about their order if we feel the order would not be a proper fit.  We have saved many customers over the years from making a bad purchase that won't work properly on their vehicle.  We are not about just making a sell, but making sure that the customer gets a wheel that looks great, fits great, and is priced great.  With 18 years of online experience we…

New Truck Rim Trends for 2018

Something new for 2018 is being introduced by Moto Metal.  It's their latest innovation they call the Moto Metal MO989 Change Up.  There has been a trend in recent years for manufacturer's to have inserts that fit in the center of the wheel.  These inserts may come in different colors which allows you to accent the wheel in different color combinations.  For 2018 Moto Metal has introduced an insert that can be installed in multiple positions giving the wheel a whole new style.  So if you get bored with one set up, just move the insert to a different position and presto, you have a new wheel style.  Here are some pictures of position options of the insert and how it makes this wheel look.

Position 1
20x12 MO989 Change Up Position 2

Position 3

Position 4

Position 5

Position 6

Position 7

This wheel is being introduced for lifted 4x4 trucks in 20x12 rim sizes.  So if you've got a lifted 4x4 truck and wanting something a new and different, the Moto Metal 989 may be just what you…