Tire Size Box

265/55R15 vs 265/65R15

265/65R15 compared with 265/55R15

+7.9% diameter, 0.0" width

265/65R15 is 28.56" tall vs 26.48". More than the 3% rule of thumb, so check carefully before switching.

26.5"15" rim5.7"10.4" wide
265/55R15 (solid) compared with 265/65R15 (dashed outline), drawn to scale

With 265/65R15 tires, when your speedometer says 60 mph you are really going

64.7 mph

265/65R15 is +2.09 inches (+7.9%) in overall diameter. That is more than the 3% most shops and makers recommend.

265/55R15265/65R15Difference%
Overall diameter26.48"28.56"+2.09"+7.9%
Section width10.43"10.43"0.00"0.0%
Sidewall height5.74"6.78"+1.04"+18.2%
Circumference83.18"89.73"+6.56"+7.9%
Revolutions per mile761.7706.1−55.6−7.3%

Speedometer difference

If your vehicle came with 265/55R15 and you fit 265/65R15, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.6 mph+1.6 mph
30 mph32.4 mph+2.4 mph
40 mph43.2 mph+3.2 mph
50 mph53.9 mph+3.9 mph
60 mph64.7 mph+4.7 mph
65 mph70.1 mph+5.1 mph
70 mph75.5 mph+5.5 mph
75 mph80.9 mph+5.9 mph
80 mph86.3 mph+6.3 mph

Each size on its own

Questions

Which is bigger, 265/55R15 or 265/65R15?
265/65R15 is taller by 2.09 inches (28.56" vs 26.48"). 265/55R15 is the same width.
Can I replace 265/55R15 with 265/65R15?
It is not recommended without checking carefully. The diameter difference is +7.9%, 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 265/65R15 change my speedometer?
When your speedometer reads 60 mph with 265/65R15 fitted (calibrated for 265/55R15), your real speed is 64.7 mph. Your odometer will under-count miles by about 7.9%.
Will 265/65R15 lift my vehicle?
Ride height changes by half the diameter difference: +1.04 inches of ground clearance at the axle.

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