235/50R18 tire size in inches

Nominal 235/50R18 dimensions

Overall diameter

27.25 in692.2 mm

Section width

9.25 in235 mm

Sidewall height

4.63 in117.5 mm

Circumference

85.61 in2,174.6 mm

Rim diameter

18 in

Revolutions per mile

740nominal, from geometric circumference

Inch notation

27.3x9.3R18approximate

Where 235/50R18 fits

• Inch class: 27.25 in is 0.25 in more than a true 27 inches, inside the 27-inch class (26.50 to 27.49 in).
• Profile: the 18-inch rim plus two 4.63 in sidewalls make up the overall diameter, and the sidewalls are 34% of it. At 50 series that is a mid profile, between low-profile performance sizes and tall truck sizes.
• Same 18-inch rim: the next taller catalog size is 235/60R18 (29.10 in, +6.79%) and the next shorter is 225/50R18 (26.86 in, -1.44%).
• Same 235 mm width: the closest in diameter are 235/60R16 (27.10 in, -0.55%), 235/55R17 (27.18 in, -0.27%), 235/70R15 (27.95 in, +2.57%), 235/65R16 (28.03 in, +2.85%). At the same width, a different profile or rim changes sidewall height and overall diameter, not section width.

Reading the marking: 235 is the section width in millimeters, 50 is the sidewall height as a percentage of that width, and R18 means radial construction for a 18-inch rim. Percentages are measured from 235/50R18.

Similar sizes on other rim diameters

Within 3% of 235/50R18's overall diameter, nearest first. The speed column is the actual speed when a speedometer calibrated for 235/50R18 reads 60 mph.

For a size without a comparison page, open 235/50R18 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 235/50R18

None keeps the 18-inch rim; each one changes wheel diameter. Diameter changes are measured from 235/50R18.