305/70R16 Tire Size in Inches

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

305/70R16
32.8" tall × 12.0" wide
On a 16-inch wheel · roughly 32.8x12.0R16 in flotation sizing
MeasurementInchesMillimetres
Overall diameter32.81833
Section width12.01305
Sidewall height8.41213.5
Wheel diameter16406
Circumference103.12618
Revolutions per mile615 (382 per km)

What 305/70R16 means

305 is the section width in millimetres (12.0 in). 70 is the aspect ratio: the sidewall is 70% as tall as the tire is wide, which works out to 213.5 mm or 8.4 in. R16 is a radial tire for a 16-inch wheel.

Overall diameter is the wheel plus two sidewalls: 16 + 2 × 8.41 = 32.8 inches. These are the nominal dimensions every maker builds to; a real 305/70R16 can measure a few tenths of an inch differently by model and inflation.

Closest equivalent sizes

Common sizes within the usual 3% of 305/70R16's overall diameter. Confirm load index, speed rating and rim width before swapping.

SizeDiameterWidthChangeSpeedometer at 60
305/45R22 new wheels 32.8 in 12.0 in -0.0% really 60.0 mph
285/75R16 32.8 in 11.2 in +0.1% really 60.0 mph
295/55R20 new wheels 32.8 in 11.6 in -0.1% really 59.9 mph
285/70R17 new wheels 32.7 in 11.2 in -0.3% really 59.8 mph
275/60R20 new wheels 33.0 in 10.8 in +0.6% really 60.3 mph
305/65R17 new wheels 32.6 in 12.0 in -0.6% really 59.6 mph

Speedometer if you switch to 285/75R16

Your speedometer stays calibrated for 305/70R16. 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 305/70R16 with any size →

Shop 305/70R16 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 305/70R16 tire is 32.8 inches (833 mm) tall overall. That is the 16-inch wheel plus two sidewalls of 8.4 inches each (70% of the 305 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 305 mm, or 12.0 inches, measured sidewall to sidewall on the recommended rim width. The tread itself is narrower than that. In flotation sizing, 305/70R16 is roughly a 32.8x12.0R16.

305/45R22 is the closest common size, at -0.0% overall diameter (32.8 in against 32.8 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 615 revolutions per mile (382 per kilometre), from its 32.8-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 16-inch sizes

195/55R16 195/60R16 195/65R16 205/50R16 205/55R16 205/60R16 205/65R16 215/55R16 215/60R16 215/65R16 215/70R16 215/85R16 225/50R16 225/55R16 225/60R16 225/65R16 225/70R16 225/75R16 235/60R16 235/65R16 235/70R16 235/75R16 235/85R16 245/70R16 245/75R16 255/65R16 255/70R16 265/70R16 265/75R16 285/75R16 205/45R16 255/85R16 275/70R16 315/75R16