Section Width545 mm (21.5")
Aspect Ratio42%
Rim Diameter18"
Overall Diameter915 mm (36.0")
Sidewall Height229 mm
Circumference2875 mm
545/42R18 — Buy Tires

Everything to know about the 545/42R18 tire size

Size geometry

A 545/42R18 tire has a 545mm section width and a 42% aspect ratio, mounted on a 18-inch rim. Sidewall height works out to 228.9mm (9.01") and overall outside diameter is 915.0mm (36.02"). At highway speed the tire completes about 348 revolutions per kilometre — your speedometer and odometer were calibrated against this number.

Direct substitute sizes

If 545/42R18 is unavailable, the closest same-diameter substitutes on the same rim are 535/43R18 and 555/41R18. Both keep your speedometer reading within 1% — safe for daily use, ABS, and stability control. Always verify load and speed ratings before swapping.

Plus / minus sizing options

For a 545/42R18 you can upsize to 555/39R19 (plus-one) to fit a larger wheel without changing the speedometer reading, or downsize to 535/45R17 (minus-one) for a softer ride or winter setup. Both stay inside the Âą3% diameter tolerance that ABS and TPMS systems expect.

Vehicle compatibility

0 vehicles in our database run the 545/42R18 tire size from the factory. Aftermarket fitment depends on rim width, offset, and clearance — match these specs to your wheel before purchasing tires.

Vehicles Using 545/42R18

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