255/30R22 Tire Size in Inches

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

255/30R22
28.0" tall × 10.0" wide
On a 22-inch wheel · roughly 28.0x10.0R22 in flotation sizing
MeasurementInchesMillimetres
Overall diameter28.02712
Section width10.04255
Sidewall height3.0176.5
Wheel diameter22559
Circumference88.02236
Revolutions per mile720 (447 per km)

What 255/30R22 means

255 is the section width in millimetres (10.0 in). 30 is the aspect ratio: the sidewall is 30% as tall as the tire is wide, which works out to 76.5 mm or 3.0 in. R22 is a radial tire for a 22-inch wheel.

Overall diameter is the wheel plus two sidewalls: 22 + 2 × 3.01 = 28.0 inches. These are the nominal dimensions every maker builds to; a real 255/30R22 can measure a few tenths of an inch differently by model and inflation.

Closest equivalent sizes

Common sizes within the usual 3% of 255/30R22's overall diameter. Confirm load index, speed rating and rim width before swapping.

SizeDiameterWidthChangeSpeedometer at 60
235/65R16 new wheels 28.0 in 9.3 in +0.0% really 60.0 mph
255/40R20 new wheels 28.0 in 10.0 in +0.0% really 60.0 mph
255/45R19 new wheels 28.0 in 10.0 in +0.0% really 60.0 mph
215/65R17 new wheels 28.0 in 8.5 in -0.1% really 60.0 mph
285/40R19 new wheels 28.0 in 11.2 in -0.2% really 59.9 mph
235/70R15 new wheels 28.0 in 9.3 in -0.3% really 59.8 mph

Speedometer if you switch to 235/65R16

Your speedometer stays calibrated for 255/30R22. With a taller tire you travel faster than it shows.

Speedometer readsTrue speed
30 mph30.0 mph
45 mph45.0 mph
55 mph55.0 mph
65 mph65.0 mph
75 mph75.0 mph
Compare 255/30R22 with any size →

Shop 255/30R22 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 255/30R22 tire is 28.0 inches (712 mm) tall overall. That is the 22-inch wheel plus two sidewalls of 3.0 inches each (30% of the 255 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 255 mm, or 10.0 inches, measured sidewall to sidewall on the recommended rim width. The tread itself is narrower than that. In flotation sizing, 255/30R22 is roughly a 28.0x10.0R22.

235/65R16 is the closest common size, at +0.0% overall diameter (28.0 in against 28.0 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 720 revolutions per mile (447 per kilometre), from its 28.0-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 22-inch sizes

265/40R22 275/40R22 285/40R22 285/45R22 305/40R22 265/35R22 285/35R22 295/30R22 305/45R22