Section Width185 mm (7.3")
Aspect Ratio27%
Rim Diameter18"
Overall Diameter557 mm (21.9")
Sidewall Height50 mm
Circumference1750 mm
185/27R18 — Buy Tires

Everything to know about the 185/27R18 tire size

Size geometry

A 185/27R18 tire has a 185mm section width and a 27% aspect ratio, mounted on a 18-inch rim. Sidewall height works out to 50.0mm (1.97") and overall outside diameter is 557.1mm (21.93"). At highway speed the tire completes about 571 revolutions per kilometre — your speedometer and odometer were calibrated against this number.

Direct substitute sizes

If 185/27R18 is unavailable, the closest same-diameter substitutes on the same rim are 175/29R18 and 195/26R18. 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 185/27R18 you can upsize to 195/19R19 (plus-one) to fit a larger wheel without changing the speedometer reading, or downsize to 175/36R17 (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 185/27R18 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 185/27R18

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