Wheel Offset and Clearance Calculator
Compare inner and outer wheel bead-seat positions and axle track change from width, offset and an optional new-wheel spacer.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Compute bead-seat edge positions relative to the hub plane using width halves and effective offsets, then subtract original positions.
Outer=W/2−ET+spacer; inner reach=W/2+ET−spacer
Worked example
Changing from 7 in ET45 to 8 in ET35 without spacers moves the outer bead seat 22.7 mm outward, reduces inner clearance by 2.7 mm and increases nominal axle track by 20 mm.
Assumptions and input details
Positive offset places the mounting surface outboard of the wheel centerline. New effective offset subtracts the entered spacer; no original spacer is modeled. Dimensions use bead seats, excluding rim-flange thickness and tire sidewalls. This geometry does not determine fitment, rubbing, brake clearance, hardware compatibility or handling suitability.
References: Tire Rack: wheel-offset definition
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
Choose from 23 length definitions, including explicitly labelled regional measures. Area conversions square the length factor; geometric volumes cube it.
Regional measures are not interchangeable merely because their names look similar. This is a documented selection, not a claim to include every historical unit.
NIST measurement tables · Japanese traditional units · Mainland China and Hong Kong unit distinctions
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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