Late-model half-tons and heavy-duty trucks often ship on 18-inch wheels, where the factory 275/70R18 is a common starting point. Stepping to a 285/75R18 adds a taller sidewall and moves you toward a true 34-inch tire: more clearance and a beefier look, with a manageable speedometer offset that the results below quantify exactly.

Use the live comparison above to see the exact diameter, circumference, revs/mile, and speedometer error between 275/70R18 and 285/75R18. Change either size to explore a different pairing, or open the full Tire Size calculator to start from scratch.