About Sidewaller
Free tire and wheel calculators that are quick to use on a phone at the tire shop.
What it does
Sidewaller works out tire dimensions, compares sizes, corrects your speedometer, recalculates gearing, checks wheel offset and estimates pressure for a new size. Every page works without an account.
Where the numbers come from
Dimensions are calculated from the nominal size printed on the tire, using the standard formulas tire makers publish. Real tires vary by brand, tread depth and wheel width, so treat the results as a guide and check the maker’s spec sheet before you buy.
How the site is paid for
The site is free to use. Store links are plain searches on the store’s own site.
Last updated 2026-10-28.