CompareWheels

Sources & corrections

Our calculations use nominal tire notation and basic geometry. The methodology page documents each formula, its assumptions and reference material.

Calculation references

• Tire Rack: calculating tire dimensions — nominal width, aspect ratio, diameter and differences from measured dimensions.
• Discount Tire: offset and backspacing — wheel terminology and physical measurements.
• Bridgestone passenger and light truck tire resource manual — manufacturer reference material.

How we use these sources

References explain notation and geometry; they are not a vehicle fitment database. Our backspacing result stops at the bead seat and excludes the physical rim flange. For a particular installation, use the wheel and tire manufacturer’s product specifications and the vehicle’s requirements.

We have retired vehicle specifications and tire review pages whose sources could not be substantiated. We currently make no claim to have a verified fitment database or live price service.

Report a calculation error

For a correction, send the URL, input values, expected result and supporting manufacturer document to data@comparewheels.com.