Tire Size Box

225/65R15 vs 225/75R15

225/75R15 compared with 225/65R15

+6.7% diameter, 0.0" width

225/75R15 is 28.29" tall vs 26.52". More than the 3% rule of thumb, so check carefully before switching.

26.5"15" rim5.8"8.9" wide
225/65R15 (solid) compared with 225/75R15 (dashed outline), drawn to scale

With 225/75R15 tires, when your speedometer says 60 mph you are really going

64.0 mph

225/75R15 is +1.77 inches (+6.7%) in overall diameter. That is more than the 3% most shops and makers recommend.

225/65R15225/75R15Difference%
Overall diameter26.52"28.29"+1.77"+6.7%
Section width8.86"8.86"0.00"0.0%
Sidewall height5.76"6.64"+0.89"+15.4%
Circumference83.30"88.87"+5.57"+6.7%
Revolutions per mile760.6713.0−47.6−6.3%

Speedometer difference

If your vehicle came with 225/65R15 and you fit 225/75R15, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.3 mph+1.3 mph
30 mph32.0 mph+2.0 mph
40 mph42.7 mph+2.7 mph
50 mph53.3 mph+3.3 mph
60 mph64.0 mph+4.0 mph
65 mph69.3 mph+4.3 mph
70 mph74.7 mph+4.7 mph
75 mph80.0 mph+5.0 mph
80 mph85.3 mph+5.3 mph

Each size on its own

Questions

Which is bigger, 225/65R15 or 225/75R15?
225/75R15 is taller by 1.77 inches (28.29" vs 26.52"). 225/65R15 is the same width.
Can I replace 225/65R15 with 225/75R15?
It is not recommended without checking carefully. The diameter difference is +6.7%, more than the 3% most shops and makers allow. It will throw off the speedometer and may affect ABS, stability control and clearance.
How much will 225/75R15 change my speedometer?
When your speedometer reads 60 mph with 225/75R15 fitted (calibrated for 225/65R15), your real speed is 64.0 mph. Your odometer will under-count miles by about 6.7%.
Will 225/75R15 lift my vehicle?
Ride height changes by half the diameter difference: +0.89 inches of ground clearance at the axle.

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