Wheel Offset Calculator Visualizer
Understanding how new wheels and tires will fit on your vehicle is crucial for both aesthetics and functionality. This Wheel Offset Calculator Visualizer helps you compare your current wheel and tire setup to a potential new one, showing you exactly how much your wheels and tires will move relative to your suspension and fenders.
Current Wheel & Tire Setup
New Wheel & Tire Setup
Understanding Wheel Offset & Fitment
Wheel offset is a critical measurement that determines how your wheel and tire assembly sits within your vehicle's fender wells. It's the distance from the wheel's mounting surface (where it bolts to the hub) to the centerline of the wheel.
- Positive Offset: The mounting surface is towards the front (outboard) face of the wheel. This means the wheel sits further inward towards the suspension. Most front-wheel-drive cars and newer rear-wheel-drive cars use positive offset.
- Negative Offset: The mounting surface is towards the back (inboard) face of the wheel. This pushes the wheel further outward from the suspension, often resulting in a "deeper dish" look. Common on older rear-wheel-drive cars and trucks.
- Zero Offset: The mounting surface is exactly at the centerline of the wheel.
Other Key Terms:
- Wheel Width: Measured in inches, this is the distance between the inner edges of the wheel flanges (where the tire beads sit). It's not the overall width of the wheel.
- Tire Section Width: Measured in millimeters, this is the width of the tire from sidewall to sidewall at its widest point when mounted on a specified rim.
- Backspacing: The distance from the mounting surface to the inner edge of the wheel. It directly impacts inner clearance with suspension components, brakes, and inner fender liners.
- Inner Clearance: The space between the wheel/tire and the vehicle's suspension, brakes, and chassis components. Insufficient inner clearance can lead to rubbing.
- Outer Position (Poke/Tuck): How far the wheel and tire extend outwards from the hub towards the fender. Too much "poke" can cause the tire to rub against the fender lip, especially during turns or suspension compression.
This calculator helps you visualize the impact of changing your wheel width, offset, and tire width on these critical fitment aspects. A positive change in "inward" movement means less inner clearance, while a positive change in "outward" movement means more "poke" towards the fender.
function calculateWheelOffset() { var currentWheelWidth = parseFloat(document.getElementById('currentWheelWidth').value); var currentOffset = parseFloat(document.getElementById('currentOffset').value); var currentTireWidth = parseFloat(document.getElementById('currentTireWidth').value); var newWheelWidth = parseFloat(document.getElementById('newWheelWidth').value); var newOffset = parseFloat(document.getElementById('newOffset').value); var newTireWidth = parseFloat(document.getElementById('newTireWidth').value); var resultDiv = document.getElementById('wheelOffsetResult'); resultDiv.innerHTML = "; if (isNaN(currentWheelWidth) || isNaN(currentOffset) || isNaN(currentTireWidth) || isNaN(newWheelWidth) || isNaN(newOffset) || isNaN(newTireWidth) || currentWheelWidth <= 0 || currentTireWidth <= 0 || newWheelWidth <= 0 || newTireWidth 0) { innerClearanceText = 'The new wheel will move ' + changeInnerClearance.toFixed(2) + ' inches further INWARD towards the suspension/brakes, reducing inner clearance.'; } else if (changeInnerClearance < 0) { innerClearanceText = 'The new wheel will move ' + Math.abs(changeInnerClearance).toFixed(2) + ' inches further OUTWARD away from the suspension/brakes, increasing inner clearance.'; } else { innerClearanceText = 'The inner edge of the new wheel will remain in the SAME position relative to the suspension/brakes.'; } var outerWheelPositionText = "; if (changeOuterWheelPosition > 0) { outerWheelPositionText = 'The new wheel lip will move ' + changeOuterWheelPosition.toFixed(2) + ' inches further OUTWARD, increasing "poke" towards the fender.'; } else if (changeOuterWheelPosition < 0) { outerWheelPositionText = 'The new wheel lip will move ' + Math.abs(changeOuterWheelPosition).toFixed(2) + ' inches further INWARD, increasing "tuck" away from the fender.'; } else { outerWheelPositionText = 'The outer lip of the new wheel will remain in the SAME position relative to the fender.'; } var outerTirePositionText = "; if (changeOuterTirePosition > 0) { outerTirePositionText = 'The new tire sidewall will move ' + changeOuterTirePosition.toFixed(2) + ' inches further OUTWARD, increasing tire "poke" towards the fender.'; } else if (changeOuterTirePosition < 0) { outerTirePositionText = 'The new tire sidewall will move ' + Math.abs(changeOuterTirePosition).toFixed(2) + ' inches further INWARD, increasing tire "tuck" away from the fender.'; } else { outerTirePositionText = 'The outer sidewall of the new tire will remain in the SAME position relative to the fender.'; } resultDiv.innerHTML = '