About WrenchCalc

WrenchCalc is a set of automotive calculators for tires, wheels and gearing, built to show their working.

Where the numbers come from

Tire figures come from the size code itself: width, aspect ratio and wheel diameter for metric sizes, or diameter, width and wheel for flotation sizes. Speed, odometer and engine rpm follow from the circumference. Every page shows its formula, so a result can be checked rather than trusted.

What they are not

They are not a fitment guarantee. Real parts vary by maker and wear, and what fits a particular vehicle depends on its suspension, brakes and bodywork.

Corrections

If a result looks wrong, email hello@wrenchcalc.com with the inputs you used and what you compared against.