255/65R18 tire size

A 255/65R18 tire is 255 mm wide with a sidewall 65% of its width (165.8 mm), fits a 18-inch rim and has an overall diameter of 789 mm (31.1 in).

DimensionMetricImperial
Section width255 mm10.04 in
Sidewall height165.8 mm6.53 in
Rim diameter457.2 mm18 in
Overall diameter788.7 mm31.05 in
Circumference2,477.8 mm97.55 in
Revolutions404 per km650 per mile

Reading the size 255/65R18

255Width in mm65Aspect 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 255/65R18

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
255/70R17789 mm+0.0%100.0Compare
245/75R17799 mm+1.3%101.3Compare
265/70R16777 mm-1.4%98.6Compare
265/65R17776 mm-1.6%98.4Compare
265/65R18802 mm+1.6%101.6Compare
265/60R18775 mm-1.7%98.3Compare
245/70R17775 mm-1.8%98.2
265/70R17803 mm+1.8%101.8

Compare 255/65R18 with any size →

Other 18-inch sizes