225/45R18 Tire Size — Dimensions, Diameter & Compatible Vehicles

Home/225/45R18

Section Width225 mm (8.9")

Aspect Ratio45%

Rim Diameter18"

Overall Diameter660 mm (26.0")

Sidewall Height101 mm

Circumference2073 mm

225/45R18 — Buy Tires

Everything to know about the 225/45R18 tire size

Size geometry

A 225/45R18 tire has a 225mm section width and a 45% aspect ratio, mounted on a 18-inch rim. Sidewall height works out to 101.3mm (3.99") and overall outside diameter is 659.7mm (25.97"). At highway speed the tire completes about 483 revolutions per kilometre — your speedometer and odometer were calibrated against this number.

Direct substitute sizes

If 225/45R18 is unavailable, the closest same-diameter substitutes on the same rim are 215/47R18 and 235/43R18. Both keep your speedometer reading within 1% — safe for daily use, ABS, and stability control. Always verify load and speed ratings before swapping.

215/47R18 235/43R18

Plus / minus sizing options

For a 225/45R18 you can upsize to 235/38R19 (plus-one) to fit a larger wheel without changing the speedometer reading, or downsize to 215/53R17 (minus-one) for a softer ride or winter setup. Both stay inside the ±3% diameter tolerance that ABS and TPMS systems expect.

215/53R17 235/38R19

Vehicle compatibility

14 vehicles in our database run the 225/45R18 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 225/45R18

Alfa Romeo Giulia

Years: 2016 - 2026

BMW 2 Series

Years: 2021 - 2026

BMW 3 Series

Years: 2012 - 2026

BMW 4 Series

Years: 2020 - 2026

BMW M3

Years: 2000 - 2006

BMW Z4

Years: 2018 - 2026

DS Automobiles DS 4

Years: 2011 - 2018

GAC Motor Empow

Years: 2021 - 2026

Kia Soul

Years: 2008 - 2013

Mercedes-Benz C-Class

Years: 2015 - 2026

Mercedes-Benz CLA