Tire Stretch Calculator
Estimate how stretched a tire will look on a given wheel, plus the resulting overall diameter for speedometer and fender-clearance reference.
How it works
The calculator uses FitmentHQ's section-to-width ratio method: the difference between the tire's section width (mm) and the wheel's width (mm) divided by the wheel width. Negative ratios indicate the tire is narrower than the wheel — that's stretch.
The classification bands (neutral / slight / moderate / aggressive / extreme) reflect community-typical thresholds. Manufacturer-rated stretch may differ — always check the tire's recommended wheel-width range before mounting.
Example
A 215/35R18 on a 9.5"-wide wheel: section width 215mm vs wheel width 241.3mm → ratio ≈ −10.9% (aggressive band). Overall diameter ≈ 23.9".
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Disclaimer
Stretch is cosmetic only. Use only on properly rated wheels. Not for daily / high-load use. These outputs are approximations — always physically test-fit components before final installation.