235/55R18 tire size

A 235/55R18 tire is 235 mm wide with a sidewall 55% of its width (129.2 mm), fits a 18-inch rim and has an overall diameter of 716 mm (28.2 in).

DimensionMetricImperial
Section width235 mm9.25 in
Sidewall height129.2 mm5.09 in
Rim diameter457.2 mm18 in
Overall diameter715.7 mm28.18 in
Circumference2,248.4 mm88.52 in
Revolutions445 per km716 per mile

Reading the size 235/55R18

235Width in mm55Aspect 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 235/55R18

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
235/50R19718 mm+0.3%100.3Compare
235/60R17714 mm-0.3%99.7Compare
235/65R16712 mm-0.5%99.5Compare
215/65R17711 mm-0.6%99.4Compare
225/70R16721 mm+0.8%100.8Compare
215/70R16707 mm-1.2%98.8Compare
225/65R17724 mm+1.2%101.2
225/55R18705 mm-1.5%98.5

Compare 235/55R18 with any size →

Other 18-inch sizes