225/70R15 Tire Size in Inches

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

225/70R15
27.4" tall × 8.9" wide
On a 15-inch wheel · roughly 27.4x8.9R15 in flotation sizing
MeasurementInchesMillimetres
Overall diameter27.40696
Section width8.86225
Sidewall height6.20157.5
Wheel diameter15381
Circumference86.12187
Revolutions per mile736 (457 per km)

What 225/70R15 means

225 is the section width in millimetres (8.9 in). 70 is the aspect ratio: the sidewall is 70% as tall as the tire is wide, which works out to 157.5 mm or 6.2 in. R15 is a radial tire for a 15-inch wheel.

Overall diameter is the wheel plus two sidewalls: 15 + 2 × 6.20 = 27.4 inches. These are the nominal dimensions every maker builds to; a real 225/70R15 can measure a few tenths of an inch differently by model and inflation.

Closest equivalent sizes

Common sizes within the usual 3% of 225/70R15's overall diameter. Confirm load index, speed rating and rim width before swapping.

SizeDiameterWidthChangeSpeedometer at 60
235/45R19 new wheels 27.3 in 9.3 in -0.3% really 59.8 mph
215/55R18 new wheels 27.3 in 8.5 in -0.3% really 59.8 mph
225/65R16 new wheels 27.5 in 8.9 in +0.4% really 60.2 mph
235/50R18 new wheels 27.3 in 9.3 in -0.5% really 59.7 mph
275/35R20 new wheels 27.6 in 10.8 in +0.6% really 60.4 mph
235/55R17 new wheels 27.2 in 9.3 in -0.8% really 59.5 mph

Speedometer if you switch to 235/45R19

Your speedometer stays calibrated for 225/70R15. With a shorter tire you travel slower than it shows.

Speedometer readsTrue speed
30 mph29.9 mph
45 mph44.9 mph
55 mph54.8 mph
65 mph64.8 mph
75 mph74.8 mph
Compare 225/70R15 with any size →

Shop 225/70R15 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 225/70R15 tire is 27.4 inches (696 mm) tall overall. That is the 15-inch wheel plus two sidewalls of 6.2 inches each (70% of the 225 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 225 mm, or 8.9 inches, measured sidewall to sidewall on the recommended rim width. The tread itself is narrower than that. In flotation sizing, 225/70R15 is roughly a 27.4x8.9R15.

235/45R19 is the closest common size, at -0.3% overall diameter (27.3 in against 27.4 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 736 revolutions per mile (457 per kilometre), from its 27.4-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 225/75R15 235/70R15 235/75R15