1. What is Rim Offset?

Rim offset is the distance between the wheel's mounting surface and its centerline, measured in millimeters. It determines how far the wheel will sit in or out from the vehicle's hub.

2. How Offset is Calculated

The calculator uses the offset formula:

Where:

• Measured Offset — Distance from wheel mounting surface to inner edge (backspacing)
• Wheel Width — Total width of the wheel (in mm)

Explanation: Positive offset means the mounting surface is toward the outside face of the wheel. Negative offset means it's toward the inside.

3. Importance of Correct Offset

Details: Proper offset ensures wheels fit correctly without rubbing suspension components or fenders. Incorrect offset can affect handling, bearing wear, and safety.

4. Using the Calculator

Tips: Measure backspacing from the mounting surface to the inner edge of the wheel. Enter wheel width in millimeters (measured from bead seat to bead seat).

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between offset and backspacing?
A: Backspacing is the total distance from mounting surface to inner edge, while offset is relative to the wheel centerline.

Q2: What are typical offset values?
A: Most factory wheels have positive offsets (usually +35 to +45mm). Performance cars may have lower positive offsets.

Q3: Can wrong offset damage my car?
A: Yes, extreme offsets can stress wheel bearings, affect handling, and cause tire rubbing.

Q4: How does offset affect wheel fitment?
A: Lower offset pushes wheels outward, higher offset tucks them inward. Each 6mm change equals about 1/4" position change.

Q5: Should I match factory offset?
A: Generally yes, unless making specific modifications. Consult a wheel specialist when changing sizes significantly.