175/65R15 Tire Size in Inches

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

175/65R15
24.0" tall × 6.9" wide
On a 15-inch wheel · roughly 24.0x6.9R15 in flotation sizing
MeasurementInchesMillimetres
Overall diameter23.96609
Section width6.89175
Sidewall height4.48113.8
Wheel diameter15381
Circumference75.31912
Revolutions per mile842 (523 per km)

What 175/65R15 means

175 is the section width in millimetres (6.9 in). 65 is the aspect ratio: the sidewall is 65% as tall as the tire is wide, which works out to 113.8 mm or 4.5 in. R15 is a radial tire for a 15-inch wheel.

Overall diameter is the wheel plus two sidewalls: 15 + 2 × 4.48 = 24.0 inches. These are the nominal dimensions every maker builds to; a real 175/65R15 can measure a few tenths of an inch differently by model and inflation.

Closest equivalent sizes

Common sizes within the usual 3% of 175/65R15's overall diameter. Confirm load index, speed rating and rim width before swapping.

SizeDiameterWidthChangeSpeedometer at 60
205/50R16 new wheels 24.1 in 8.1 in +0.5% really 60.3 mph
185/60R15 23.7 in 7.3 in -0.9% really 59.5 mph
185/70R14 new wheels 24.2 in 7.3 in +1.0% really 60.6 mph
195/60R15 24.2 in 7.7 in +1.1% really 60.6 mph
195/55R16 new wheels 24.4 in 7.7 in +2.0% really 61.2 mph
185/65R14 new wheels 23.5 in 7.3 in -2.0% really 58.8 mph

Speedometer if you switch to 185/60R15

Your speedometer stays calibrated for 175/65R15. With a shorter tire you travel slower than it shows.

Speedometer readsTrue speed
30 mph29.7 mph
45 mph44.6 mph
55 mph54.5 mph
65 mph64.4 mph
75 mph74.3 mph
Compare 175/65R15 with any size →

Shop 175/65R15 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 175/65R15 tire is 24.0 inches (609 mm) tall overall. That is the 15-inch wheel plus two sidewalls of 4.5 inches each (65% of the 175 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 175 mm, or 6.9 inches, measured sidewall to sidewall on the recommended rim width. The tread itself is narrower than that. In flotation sizing, 175/65R15 is roughly a 24.0x6.9R15.

205/50R16 is the closest common size, at +0.5% overall diameter (24.1 in against 24.0 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 842 revolutions per mile (523 per kilometre), from its 24.0-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 15-inch sizes

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 235/75R15