Rim Offset Definition
Simple Rim Offset Picture


Wheel Offset Calculator v2.0


Another simple calculator for figuring out the offset of a rim when you change the size of it. The measurements are usually pretty easy with the rim off the car, and it is always best to start with these numbers as guidelines.  Since I'm not an artist, images are gathered from the web with any branding left intact. The several images show where to measure and what a positive, zero and negative offset wheel might look like. The image of the Fikse wheel cutaway has a lot more definitions for wheel related terms



Wheel Size Offset Calculator
Current Wheel Width  
Current Wheel Offset (mm)
New Wheel Width  
New Wheel Offset (mm)
Wheel Edge Movement Changes
Suspension Side Change  Inches   mm
Fender Side Change  Inches   mm

Here's how to interpret the results:


If the 'Suspension Side Change' field is a NEGATIVE value then the new rim offset has moved the edge of the rim towards the suspension. If a POSITIVE value then the new sized rim edge has moved away from the suspension.

If the 'Fender Side Change' field is a NEGATIVE value then the new rim offset has moved the edge away from the edge of the fender (towards the inside). If a POSITIVE value then the new sized rim edge has
moved towards the inside of the fender.

If either field returns ZERO then no change as you might have imagined.

NEW NEW NEW
Want to see How much Fender Room adding some Negative Camber Will Give, Offset Conversion?
CAMBER OFFSET CALCULATOR
Convert Offset to Backspace
Convert Backspace to Offset
Enter the following data -

Current Wheel Width - Your current wheel width
Current Wheel Offset - Your current wheel offset
New Wheel Width - Your new wheel width
New Wheel Offset - Your new wheel offset

Note: Often front wheel and rear wheel offsets are different. And
wheel offset is generally expressed in Millimeters.
 
Hit the SAMPLE button to see how some typical calculations will
look. RESET will clear out the form and the CALCULATE button
will do the work. If you find any problems let me know!

EZ Rim Offset Helper
Zero Offset
The hub mounting surface is even with the centerline of the wheel.

Positive Offset
The hub mounting surface is toward the front or wheel side of  the wheel. Positive offset wheels are generally found on front wheel drive cars and newer rear drive cars.

Negative Offset
The hub mounting surface is toward the back or brake side of the wheels centerline.

Click the Image to jump to the Wheel Offset Page with LARGER image
Click the above drop down menu for more!
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