How to Measure Wheel Sizes
If you are unsure the overall size of your wheels, there are a few things to consider when attempting to measure the dimensions. You will want to find the following:
- Diameter
- Width
- Offset
- Backspacing
- Bolt Patterns
How To Measure Wheel Diameter
With the Wheel Diameter, keep in mind that there are two measurements to consider: Overall Wheel Diameter and Actual Wheel Diameter.
When measuring for the Overall diameter, you will want to measure from the outside lip to outside lip of the wheel with a measuring tape (Shown by the Green Line in the photo below).
When measuring for the Actual Diameter, you will want to measure from the inside of the Barrel of the wheel (Shown by the Red Line in the above photo). Example: A wheel with an actual Diameter of 18” will have an overall diameter of around 19.5”.
How To Measure Wheel Width
Measuring the Wheel width or rim width is similar to measuring the Diameter. You will want to measure wheel width from the Barrel Section and not the overall outside width (See Picture Below).
How To Measure Wheel Offset
The offset of a wheel is the distance from the hub mounting surface to the center line of the wheel. This is an important measurement to keep an eye on when choosing your next set of Mustang wheels. The wheel offset is measured in millimeters and results in three different types of offsets.
The Three Types of Offset
- Positive Offset: The hub mounting surface is toward the face of the wheel.
- Negative Offset: The hub mounting surface is toward the back of the wheel.
- Zero Offset: The hub mounting surface is even with the centerline of the wheel.
How To Measure Wheel Backspacing
The backspacing is the distance from where the hub section of the wheel contacts the hub surface of the car to the back lip of the wheel (See picture below). Backspacing is always measured in inches and is closely related to the offset so that means when you change one it immediately affects the other.
This is extremely important because it determines the clearance of the wheel in the wheel well. Also, it affects how much the wheel will stick out past the fender. You can measure a wheel’s backspacing by running a straight edge across the rim bead (without a tire) and dropping another straight edge or Tape measure/ruler down to the wheel face, measuring that distance. (See picture below) You will also need to take into consideration the tire size.
How To Measure Wheel Bolt Pattern
The bolt pattern consists of two numbers and looks like this: 5×4.50. The first number in this example(5) indicates how many bolt holes or studs are on the vehicle while the other number (4.50) describes the diameter of the circle formed by those 5 holes or studs. They are listed in either inches or millimeter units (4.50 is inches). Another example: a bolt pattern of 4×100 indicates a pattern with 4 lugs on a circle with a diameter of 100mm.
Using these tools, you will be able to find the overall dimensions of the wheels you have! Many wheel manufacturers will also have the Diameter and Width Cast in the back of the wheel (example: 17x9) to make it easy to know the main size.
Source: Discount Tire
FAQs
How Do You Tell The Width Of A Rim?
To measure the width of a rim, you can use a ruler or tape measure to determine the distance between the inner edges of the rim where the tire sits. This measurement represents the rim width, typically expressed in inches or millimeters.
How Do You Know If A Tire Will Fit A Rim?
To determine if a tire will fit a rim, you need to ensure compatibility in terms of both diameter and width. Match the tire's diameter to the rim's diameter (e.g., 15-inch tire for a 15-inch rim) and verify that the tire's width range is suitable for the rim width. Additionally, consider aspects like tire profile and clearance to ensure proper fitment.To measure rim width, use a ruler or caliper to determine the distance between the inner edges of the rim where the tire sits. Rim offset is measured from the mounting surface to the centerline of the rim, either positive (toward the front of the rim) or negative (toward the back). Use a straightedge to measure this distance accurately.
How Do You Measure Rim Width and Offset?
To measure rim width, use a ruler or caliper to determine the distance between the inner edges of the rim where the tire sits. Rim offset is measured from the mounting surface to the centerline of the rim, either positive (toward the front of the rim) or negative (toward the back). Use a straightedge to measure this distance accurately.
