235/75R15 Tire Size in Inches

Diameter, width, sidewall and the closest equivalent sizes, computed from the size code.

235/75R15
28.9" tall × 9.3" wide
On a 15-inch wheel · roughly 28.9x9.3R15 in flotation sizing
MeasurementInchesMillimetres
Overall diameter28.88734
Section width9.25235
Sidewall height6.94176.2
Wheel diameter15381
Circumference90.72304
Revolutions per mile698 (434 per km)

What 235/75R15 means

235 is the section width in millimetres (9.3 in). 75 is the aspect ratio: the sidewall is 75% as tall as the tire is wide, which works out to 176.2 mm or 6.9 in. R15 is a radial tire for a 15-inch wheel.

Overall diameter is the wheel plus two sidewalls: 15 + 2 × 6.94 = 28.9 inches. These are the nominal dimensions every maker builds to; a real 235/75R15 can measure a few tenths of an inch differently by model and inflation.

Closest equivalent sizes

Common sizes within the usual 3% of 235/75R15's overall diameter. Confirm load index, speed rating and rim width before swapping.

SizeDiameterWidthChangeSpeedometer at 60
235/70R16 new wheels 29.0 in 9.3 in +0.3% really 60.2 mph
295/30R22 new wheels 29.0 in 11.6 in +0.3% really 60.2 mph
225/55R19 new wheels 28.7 in 8.9 in -0.5% really 59.7 mph
275/45R19 new wheels 28.7 in 10.8 in -0.5% really 59.7 mph
235/65R17 new wheels 29.0 in 9.3 in +0.5% really 60.3 mph
255/40R21 new wheels 29.0 in 10.0 in +0.5% really 60.3 mph

Speedometer if you switch to 235/70R16

Your speedometer stays calibrated for 235/75R15. With a taller tire you travel faster than it shows.

Speedometer readsTrue speed
30 mph30.1 mph
45 mph45.1 mph
55 mph55.1 mph
65 mph65.2 mph
75 mph75.2 mph
Compare 235/75R15 with any size →

Shop 235/75R15 tires

Check the load index and speed rating on your door-jamb placard before you buy, especially for LT tires used for towing.

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Frequently Asked Questions

A 235/75R15 tire is 28.9 inches (734 mm) tall overall. That is the 15-inch wheel plus two sidewalls of 6.9 inches each (75% of the 235 mm section width). Expect a real tire to measure within a few tenths of an inch of this, depending on the model and inflation.

The section width is 235 mm, or 9.3 inches, measured sidewall to sidewall on the recommended rim width. The tread itself is narrower than that. In flotation sizing, 235/75R15 is roughly a 28.9x9.3R15.

235/70R16 is the closest common size, at +0.3% overall diameter (29.0 in against 28.9 in). Most makers treat about 3% as the limit for a swap without speedometer or clearance problems, but always confirm load index, speed rating and wheel width before changing size.

About 698 revolutions per mile (434 per kilometre), from its 28.9-inch rolling diameter. Real-world figures run slightly higher because a loaded tire squats. This number is what your speedometer and odometer are calibrated against.

Last updated: October 2, 2026

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Other 15-inch sizes

175/65R15 185/55R15 185/60R15 185/65R15 195/55R15 195/60R15 195/65R15 205/60R15 205/65R15 205/70R15 205/75R15 215/60R15 215/65R15 215/70R15 215/75R15 225/60R15 225/70R15 225/75R15 235/70R15