Section Width305 mm (12.0")
Aspect Ratio18%
Rim Diameter27"
Overall Diameter796 mm (31.3")
Sidewall Height55 mm
Circumference2499 mm
305/18R27 — Buy Tires

Everything to know about the 305/18R27 tire size

Size geometry

A 305/18R27 tire has a 305mm section width and a 18% aspect ratio, mounted on a 27-inch rim. Sidewall height works out to 54.9mm (2.16") and overall outside diameter is 795.6mm (31.32"). At highway speed the tire completes about 400 revolutions per kilometre — your speedometer and odometer were calibrated against this number.

Direct substitute sizes

If 305/18R27 is unavailable, the closest same-diameter substitutes on the same rim are 295/19R27 and 315/17R27. 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 305/18R27 you can upsize to 315/13R28 (plus-one) to fit a larger wheel without changing the speedometer reading, or downsize to 295/23R26 (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 305/18R27 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 305/18R27

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