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Wheel Offset Calculator

Calculate clearance and position changes when upgrading wheels

Compare Wheel Offsets

Current Wheel

Declared width of the current wheel

mm

Distance from centerline to mounting surface

New Wheel

Declared width of the new wheel

mm

Distance from centerline to mounting surface

Offset Calculation Results

-2.7 mm
Clearance Change
Less clearance from suspension
-22.7 mm
Position Change
Wheel moves inward (toward suspension)

Wheel Specifications

Current Width:177.8 mm
New Width:203.2 mm
Width Difference:-25.4 mm
Offset Difference:+10.0 mm

Offset Types

Current Offset:Positive
New Offset:Positive
Backspacing Change:+2.7 mm
Centerline Shift:-12.7 mm

Clearance Impact Analysis

Fender Clearance:+22.7 mm

Less clearance from fender

Suspension Clearance:-2.7 mm

Less clearance from suspension

⚠️ Important Considerations

  • • Large change in fender clearance - check for interference
  • • Test fit wheels and check all clearances before final installation

Example Calculation

Scenario: Current: 7" width, 42mm offset → New: 8" width, 32mm offset
Results: -2.7mm clearance change, -22.7mm position change
Interpretation: New wheel is closer to suspension by 22.7mm with reduced clearance by 2.7mm
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Understanding Wheel Offset

+

Positive Offset

Mounting surface closer to outside edge

0

Zero Offset

Mounting surface at centerline

-

Negative Offset

Mounting surface closer to inside edge

Key Terms

Wheel Width

Distance between bead seats where tire sits

Offset

Distance from centerline to mounting surface

Backspacing

Distance from mounting surface to inner edge

Centerline

Imaginary line dividing wheel into equal halves

Understanding Wheel Offset Calculations

What is Wheel Offset?

Wheel offset is the distance between the wheel's centerline and its mounting surface. It determines how far in or out the wheel sits relative to the vehicle's suspension and body panels.

Calculation Formulas

Clearance = (W₁ - W₂)/2 + (O₁ - O₂)

Position = (W₁ - W₂)/2 - (O₁ - O₂)

Where W = width, O = offset, subscript 1 = current, 2 = new

Why Offset Matters

  • Clearance: Prevents interference with suspension components
  • Fender Gap: Affects wheel position relative to body panels
  • Handling: Changes scrub radius and steering feel
  • Bearing Load: Affects stress on wheel bearings

Safety Note

Always verify physical clearances before final installation. Computer calculations should be confirmed with test fitting to ensure safe operation.

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