2021 Lexus IS Tire Fitment

Trim fitment

About 2021 Lexus IS fitment

The 2021 Lexus IS 300 ships from the factory with 225/45R17 tires, giving a 24.97″ overall diameter and 808 revs per mile. This is the reference size the factory speedometer, odometer, ABS, and TPMS were calibrated against, so any replacement tire should stay close to 24.97″ to preserve correct readings. This model year ships in multiple configurations with different OEM tire sizes (225/45R17, 235/40R19), so confirm your exact trim badge before ordering. The smallest recommended upsize is 235/35R19 — a 2.02% diameter change — which keeps the speedometer inside factory tolerance while adding marginal ride height and sidewall compliance. The most aggressive option shown, 225/40R18, runs 0.46% taller and will likely need clearance checking on stock suspension. For a direct replacement, look for brands offering 225/45R17 in all-season, highway, or terrain-appropriate compounds — the OEM spec typically emphasizes fuel economy and tread life over grip, so aftermarket replacements often unlock better wet performance or off-road capability at similar cost. Before committing to an upsize, confirm wheel-well clearance at full steering lock and suspension compression, and verify the chosen size does not conflict with snow chains, tire-fit sensors, or any lift-kit hardware already installed.

Upsize options

Check speedometer error before upsizing