225/50R18 tire size

A 225/50R18 tire is 225 mm wide with a sidewall 50% of its width (112.5 mm), fits a 18-inch rim and has an overall diameter of 682 mm (26.9 in).

DimensionMetricImperial
Section width225 mm8.86 in
Sidewall height112.5 mm4.43 in
Rim diameter457.2 mm18 in
Overall diameter682.2 mm26.86 in
Circumference2,143.2 mm84.38 in
Revolutions467 per km751 per mile

Reading the size 225/50R18

225Width in mm50Aspect ratio (sidewall % of width)RRadial construction18Rim diameter in inches

The load index and speed rating (for example 91V) follow the size on the sidewall. Replacement tires should match or exceed the original load index and speed rating.

Alternative sizes within 3% of 225/50R18

A replacement size should stay within about 3% of the original diameter so the speedometer, ABS and transmission stay accurate. Always check clearance, load index and the vehicle manufacturer's approved sizes.

SizeDiameterDifferenceSpeedo reads 100 → actual
215/70R15682 mm-0.0%100.0Compare
245/35R20680 mm-0.4%99.6Compare
225/55R17679 mm-0.4%99.6Compare
245/40R19679 mm-0.5%99.5Compare
215/65R16686 mm+0.5%100.5Compare
255/35R20686 mm+0.6%100.6Compare
255/40R19687 mm+0.6%100.6Compare
245/45R18678 mm-0.7%99.3Compare

Compare 225/50R18 with any size →

Other 18-inch sizes