Popular 18-inch SUV comparison

235/60R18 vs 235/55R18

A 235/55R18 tire is shorter than a 235/60R18 tire while keeping the same width and wheel diameter, which lowers sidewall height and overall diameter.

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The calculator opens with 235/60R18 and 235/55R18 already filled in, including the visual tire diagram, speedometer gauge, metric toggle, and share link.

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Check fitment This size change is a little past the 3% target, so review ride height, speedometer reading, and load rating before treating it as interchangeable.

235/60R18 vs 235/55R18 dimensions summary
Measurement	235/60R18	235/55R18
Overall diameter	29.10 in	28.18 in
Sidewall height	5.55 in	5.09 in
Circumference	91.43 in	88.52 in
Revolutions per mile	693	716
Ground clearance change	0.00 in	-0.46 in
Diameter difference	0.0%	-3.2%

Height change -0.93 in -24 mm overall diameter

Speedometer at 60 mph 58.1 mph -1.9 mph difference

Diameter difference -3.2% The diameter change is between 3% and 5%, so verify clearance, gearing, load rating, and speedometer impact.

What changes between 235/60R18 and 235/55R18?

The main difference is overall diameter. 235/55R18 measures 28.18 in across, compared with 29.10 in for 235/60R18. That creates a -3.2% diameter change and a -0.46 in ground clearance change.

At an indicated 60 mph, this comparison estimates an actual speed of 58.1 mph. Use the live calculator before buying tires so you can review the visual clearance change, speedometer numbers, and shareable comparison link in one place.