Tiremason blog https://tiremason.com/blog/ Original data dives from the Tiremason engine — every figure computed by the same code as the calculators. Twelve Plus-Size Swaps, Computed: What Changing Tire Size Actually Does to Your Speedometer https://tiremason.com/blog/plus-size-swap-speedometer-computed/ https://tiremason.com/blog/plus-size-swap-speedometer-computed/ Mon, 26 Oct 2026 00:00:00 GMT We ran 12 common OE-to-plus-size tire swaps through the comparison engine: only 8 of 12 stay under the 3% line, and the worst misreads your speed by 3 mph. 3.73 vs 4.10 vs 4.56: Cruising RPM Across Six Tire Sizes, Computed https://tiremason.com/blog/ring-pinion-cruise-rpm-computed/ https://tiremason.com/blog/ring-pinion-cruise-rpm-computed/ Mon, 26 Oct 2026 00:00:00 GMT A 3.73-to-4.10 regear raises 70-mph cruise RPM by 9.9% on any tire; going 265/70R17 to 35-inch tires quietly undoes a 4.10 as if you had installed a 3.71.