275/65R18 tire size in inches

Nominal 275/65R18 dimensions

Overall diameter

32.07 in814.7 mm

Section width

10.83 in275 mm

Sidewall height

7.04 in178.8 mm

Circumference

100.77 in2,559.5 mm

Rim diameter

18 in

Revolutions per mile

629nominal, from geometric circumference

Inch notation

32.1x10.8R18approximate

Where 275/65R18 fits

• Inch class: 32.07 in is within 0.1 in of a true 32 inches, so the 32-inch label is close to exact.
• Profile: the 18-inch rim plus two 7.04 in sidewalls make up the overall diameter, and the sidewalls are 44% of it. At 65 series that is a tall profile: the extra sidewall absorbs more of each bump and flexes more in corners.
• Same 18-inch rim: 275/65R18 is the tallest 18-inch size in the catalog. The next shorter is 255/70R18 (32.06 in, -0.06%).
• Same 275 mm width: the closest in diameter are 275/40R20 (28.66 in, -10.64%), 275/35R22 (29.58 in, -7.78%), 275/60R17 (29.99 in, -6.49%), 275/70R16 (31.16 in, -2.86%). At the same width, a different profile or rim changes sidewall height and overall diameter, not section width.

Reading the marking: 275 is the section width in millimeters, 65 is the sidewall height as a percentage of that width, and R18 means radial construction for a 18-inch rim. Percentages are measured from 275/65R18.

Similar sizes on other rim diameters

Within 3% of 275/65R18's overall diameter, nearest first. The speed column is the actual speed when a speedometer calibrated for 275/65R18 reads 60 mph.

For a size without a comparison page, open 275/65R18 in the calculator and enter that size as the proposed tire.

Important: These results compare nominal dimensions. They do not confirm vehicle fitment. Actual clearance varies by tire model, approved rim width, wheel construction, suspension, alignment, body tolerances, steering angle, load, and brake geometry. Verify load and speed ratings and physically test-fit the complete setup before driving.

Physical checks before changing size

• Approved rim-width range for the exact tire model
• Load index and speed rating equal to or greater than vehicle requirements
• Brake-caliper, hub, and wheel-fastener compatibility
• Fender, liner, suspension, and full-lock steering clearance
• Clearance at full compression and under expected load
• Alignment, tire pressure, and manufacturer guidance
• Professional inspection when variance or clearance is uncertain

Published comparisons for 275/65R18

None keeps the 18-inch rim; each one changes wheel diameter. Diameter changes are measured from 275/65R18.