205/70R15 Tire Size in Inches

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

205/70R15
26.3" tall × 8.1" wide
On a 15-inch wheel · roughly 26.3x8.1R15 in flotation sizing
MeasurementInchesMillimetres
Overall diameter26.30668
Section width8.07205
Sidewall height5.65143.5
Wheel diameter15381
Circumference82.62099
Revolutions per mile767 (477 per km)

What 205/70R15 means

205 is the section width in millimetres (8.1 in). 70 is the aspect ratio: the sidewall is 70% as tall as the tire is wide, which works out to 143.5 mm or 5.6 in. R15 is a radial tire for a 15-inch wheel.

Overall diameter is the wheel plus two sidewalls: 15 + 2 × 5.65 = 26.3 inches. These are the nominal dimensions every maker builds to; a real 205/70R15 can measure a few tenths of an inch differently by model and inflation.

Closest equivalent sizes

Common sizes within the usual 3% of 205/70R15's overall diameter. Confirm load index, speed rating and rim width before swapping.

SizeDiameterWidthChangeSpeedometer at 60
215/55R17 new wheels 26.3 in 8.5 in +0.0% really 60.0 mph
235/45R18 new wheels 26.3 in 9.3 in +0.1% really 60.1 mph
235/50R17 new wheels 26.3 in 9.3 in -0.2% really 59.9 mph
235/40R19 new wheels 26.4 in 9.3 in +0.4% really 60.2 mph
215/60R16 new wheels 26.2 in 8.5 in -0.5% really 59.7 mph
215/50R18 new wheels 26.5 in 8.5 in +0.6% really 60.4 mph

Speedometer if you switch to 215/55R17

Your speedometer stays calibrated for 205/70R15. 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 205/70R15 with any size →

Shop 205/70R15 tires

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

See 205/70R15 tires on Amazon →

As an Amazon Associate we earn from qualifying purchases.

Frequently Asked Questions

A 205/70R15 tire is 26.3 inches (668 mm) tall overall. That is the 15-inch wheel plus two sidewalls of 5.6 inches each (70% of the 205 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 205 mm, or 8.1 inches, measured sidewall to sidewall on the recommended rim width. The tread itself is narrower than that. In flotation sizing, 205/70R15 is roughly a 26.3x8.1R15.

215/55R17 is the closest common size, at +0.0% overall diameter (26.3 in against 26.3 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 767 revolutions per mile (477 per kilometre), from its 26.3-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

Compare any sizes

The full calculator compares up to three sizes with speedometer error, clearance change and a to-scale diagram.

Open the tire size calculator

Other 15-inch sizes

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