Tire Size Box

265/65R18 vs 265/75R18

265/75R18 compared with 265/65R18

+6.6% diameter, 0.0" width

265/75R18 is 33.65" tall vs 31.56". More than the 3% rule of thumb, so check carefully before switching.

31.6"18" rim6.8"10.4" wide
265/65R18 (solid) compared with 265/75R18 (dashed outline), drawn to scale

With 265/75R18 tires, when your speedometer says 60 mph you are really going

64.0 mph

265/75R18 is +2.09 inches (+6.6%) in overall diameter. That is more than the 3% most shops and makers recommend.

265/65R18265/75R18Difference%
Overall diameter31.56"33.65"+2.09"+6.6%
Section width10.43"10.43"0.00"0.0%
Sidewall height6.78"7.82"+1.04"+15.4%
Circumference99.16"105.71"+6.56"+6.6%
Revolutions per mile639.0599.4−39.6−6.2%

Speedometer difference

If your vehicle came with 265/65R18 and you fit 265/75R18, 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 mph42.6 mph+2.6 mph
50 mph53.3 mph+3.3 mph
60 mph64.0 mph+4.0 mph
65 mph69.3 mph+4.3 mph
70 mph74.6 mph+4.6 mph
75 mph80.0 mph+5.0 mph
80 mph85.3 mph+5.3 mph

Each size on its own

Questions

Which is bigger, 265/65R18 or 265/75R18?
265/75R18 is taller by 2.09 inches (33.65" vs 31.56"). 265/65R18 is the same width.
Can I replace 265/65R18 with 265/75R18?
It is not recommended without checking carefully. The diameter difference is +6.6%, 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 265/75R18 change my speedometer?
When your speedometer reads 60 mph with 265/75R18 fitted (calibrated for 265/65R18), your real speed is 64.0 mph. Your odometer will under-count miles by about 6.6%.
Will 265/75R18 lift my vehicle?
Ride height changes by half the diameter difference: +1.04 inches of ground clearance at the axle.

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