Tire Size Box

225/65R15 vs 225/70R15

225/70R15 compared with 225/65R15

+3.3% diameter, 0.0" width

225/70R15 is 27.40" 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 225/70R15 (dashed outline), drawn to scale

With 225/70R15 tires, when your speedometer says 60 mph you are really going

62.0 mph

225/70R15 is +0.89 inches (+3.3%) in overall diameter. That is more than the 3% most shops and makers recommend.

225/65R15225/70R15Difference%
Overall diameter26.52"27.40"+0.89"+3.3%
Section width8.86"8.86"0.00"0.0%
Sidewall height5.76"6.20"+0.44"+7.7%
Circumference83.30"86.08"+2.78"+3.3%
Revolutions per mile760.6736.0−24.6−3.2%

Speedometer difference

If your vehicle came with 225/65R15 and you fit 225/70R15, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.7 mph+0.7 mph
30 mph31.0 mph+1.0 mph
40 mph41.3 mph+1.3 mph
50 mph51.7 mph+1.7 mph
60 mph62.0 mph+2.0 mph
65 mph67.2 mph+2.2 mph
70 mph72.3 mph+2.3 mph
75 mph77.5 mph+2.5 mph
80 mph82.7 mph+2.7 mph

Each size on its own

Questions

Which is bigger, 225/65R15 or 225/70R15?
225/70R15 is taller by 0.89 inches (27.40" vs 26.52"). 225/65R15 is the same width.
Can I replace 225/65R15 with 225/70R15?
It is not recommended without checking carefully. The diameter difference is +3.3%, 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 225/70R15 change my speedometer?
When your speedometer reads 60 mph with 225/70R15 fitted (calibrated for 225/65R15), your real speed is 62.0 mph. Your odometer will under-count miles by about 3.3%.
Will 225/70R15 lift my vehicle?
Ride height changes by half the diameter difference: +0.44 inches of ground clearance at the axle.

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