Tire Size Box

205/65R15 vs 205/75R15

205/75R15 compared with 205/65R15

+6.3% diameter, 0.0" width

205/75R15 is 27.11" tall vs 25.49". More than the 3% rule of thumb, so check carefully before switching.

25.5"15" rim5.2"8.1" wide
205/65R15 (solid) compared with 205/75R15 (dashed outline), drawn to scale

With 205/75R15 tires, when your speedometer says 60 mph you are really going

63.8 mph

205/75R15 is +1.61 inches (+6.3%) in overall diameter. That is more than the 3% most shops and makers recommend.

205/65R15205/75R15Difference%
Overall diameter25.49"27.11"+1.61"+6.3%
Section width8.07"8.07"0.00"0.0%
Sidewall height5.25"6.05"+0.81"+15.4%
Circumference80.09"85.16"+5.07"+6.3%
Revolutions per mile791.2744.0−47.1−6.0%

Speedometer difference

If your vehicle came with 205/65R15 and you fit 205/75R15, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.3 mph+1.3 mph
30 mph31.9 mph+1.9 mph
40 mph42.5 mph+2.5 mph
50 mph53.2 mph+3.2 mph
60 mph63.8 mph+3.8 mph
65 mph69.1 mph+4.1 mph
70 mph74.4 mph+4.4 mph
75 mph79.7 mph+4.7 mph
80 mph85.1 mph+5.1 mph

Each size on its own

Questions

Which is bigger, 205/65R15 or 205/75R15?
205/75R15 is taller by 1.61 inches (27.11" vs 25.49"). 205/65R15 is the same width.
Can I replace 205/65R15 with 205/75R15?
It is not recommended without checking carefully. The diameter difference is +6.3%, 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 205/75R15 change my speedometer?
When your speedometer reads 60 mph with 205/75R15 fitted (calibrated for 205/65R15), your real speed is 63.8 mph. Your odometer will under-count miles by about 6.3%.
Will 205/75R15 lift my vehicle?
Ride height changes by half the diameter difference: +0.81 inches of ground clearance at the axle.

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