TireSizeCheck

255/60R18

A 255/60R18 tire is 30.05 inches tall and 10.0 inches wide, with a 6.02-inch sidewall, mounted on a 18-inch wheel.

Overall diameter

30.05″

763 mm

Sidewall height

6.02″

153.0 mm

Tread width

255 mm

10.0″

Circumference

94.40″

7.9 ft

Revs per mile

671

417 per km

Wheel diameter

18″

aspect ratio 60%

Cross-section

Overall diameter
30.05″
Sidewall (each side)
6.02″
Wheel
18″

255/60R18 in inches and millimeters

Every dimension of a 255/60R18, converted both ways. Calculated from the size code, accurate to about 1%.

Measurement Inches Millimeters
Overall diameter (height) 30.05″ 763 mm
Tread width 10.0″ 255 mm
Sidewall height 6.02″ 153.0 mm
Wheel diameter 18″ 457 mm
Circumference 94.40″ 2398 mm

Nominal dimensions from the size code. A real tire varies by a few millimeters between manufacturers, and a loaded tire sits slightly shorter than its free diameter.

255/60R18 compared with other sizes

All 31 practical swaps involving 255/60R18 — diameter change, speedometer impact and a fit verdict for each.

255/60R18 → 245/75R16

245/75R16

Diameter −1.4% · This fits

255/60R18 → 235/60R18

235/60R18

Diameter +3.2% · Borderline. Check clearance first

255/60R18 → 255/55R18

255/55R18

Diameter +3.5% · Borderline. Check clearance first

255/60R18 → 265/60R18

265/60R18

Diameter −1.5% · This fits

255/60R18 → 245/70R16

245/70R16

Diameter +1.8% · This fits

255/60R18 → 255/70R16

255/70R16

Diameter −0.0% · This fits

255/60R18 → 255/65R17

255/65R17

Diameter −0.0% · This fits

255/60R18 → 225/60R18

225/60R18

Diameter +5.0% · Borderline. Check clearance first

255/60R18 → 235/65R18

235/65R18

Diameter +0.1% · This fits

255/60R18 → 245/60R18

245/60R18

Diameter +1.6% · This fits

255/60R18 → 245/65R18

245/65R18

Diameter −1.6% · This fits

235/65R18 → 255/60R18

235/65R18

Diameter −0.1% · This fits

245/60R18 → 255/60R18

245/60R18

Diameter −1.6% · This fits

265/60R18 → 255/60R18

265/60R18

Diameter +1.6% · This fits

245/65R18 → 255/60R18

245/65R18

Diameter +1.6% · This fits

255/55R18 → 255/60R18

255/55R18

Diameter −3.3% · Borderline. Check clearance first

255/65R18 → 255/60R18

255/65R18

Diameter +3.3% · Borderline. Check clearance first

235/60R18 → 255/60R18

235/60R18

Diameter −3.1% · Borderline. Check clearance first

275/60R18 → 255/60R18

275/60R18

Diameter +3.1% · Borderline. Check clearance first

255/65R17 → 255/60R18

255/65R17

Diameter +0.0% · This fits

255/70R16 → 255/60R18

255/70R16

Diameter +0.0% · This fits

255/50R20 → 255/60R18

255/50R20

Diameter −0.0% · This fits

225/60R18 → 255/60R18

225/60R18

Diameter −4.7% · Borderline. Check clearance first

285/60R18 → 255/60R18

285/60R18

Diameter +4.7% · Borderline. Check clearance first

265/65R18 → 255/60R18

265/65R18

Diameter +5.0% · Too big a jump

255/60R18 → 255/65R18

255/65R18

Diameter −3.2% · Borderline. Check clearance first

255/60R18 → 265/65R18

265/65R18

Diameter −4.8% · Borderline. Check clearance first

255/60R18 → 275/60R18

275/60R18

Diameter −3.0% · Borderline. Check clearance first

255/60R18 → 285/60R18

285/60R18

Diameter −4.5% · Borderline. Check clearance first

255/60R18 → 255/50R20

255/50R20

Diameter +0.0% · This fits

255/60R18 → 235/45R18

235/45R18

Diameter +14.1% · Too big a jump

Common questions

What is 255/60R18 in inches?
A 255/60R18 tire is 30.05 inches tall and 10.0 inches wide, with a 6.02-inch sidewall, mounted on a 18-inch wheel. In metric that is 763 mm tall and 255 mm wide. The circumference is 94.40 inches.
How tall is a 255/60R18 tire?
30.05 inches, or 763 mm. That is the overall diameter, wheel included. It turns about 671 times per mile, which is what your speedometer counts.
What do the numbers in 255/60R18 mean?
255 is the tread width in millimeters, 60 is the aspect ratio — the sidewall height as a percentage of the tread width — and 18 is the wheel diameter in inches. So the sidewall is 255 × 60% = 153.0 mm tall.