Tire Size Box

245/60R18 vs 245/65R18

245/65R18 compared with 245/60R18

+3.3% diameter, 0.0" width

245/65R18 is 30.54" tall vs 29.57". More than the 3% rule of thumb, so check carefully before switching.

29.6"18" rim5.8"9.6" wide
245/60R18 (solid) compared with 245/65R18 (dashed outline), drawn to scale

With 245/65R18 tires, when your speedometer says 60 mph you are really going

62.0 mph

245/65R18 is +0.96 inches (+3.3%) in overall diameter. That is more than the 3% most shops and makers recommend.

245/60R18245/65R18Difference%
Overall diameter29.57"30.54"+0.96"+3.3%
Section width9.65"9.65"0.00"0.0%
Sidewall height5.79"6.27"+0.48"+8.3%
Circumference92.91"95.94"+3.03"+3.3%
Revolutions per mile681.9660.4−21.5−3.2%

Speedometer difference

If your vehicle came with 245/60R18 and you fit 245/65R18, 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 mph51.6 mph+1.6 mph
60 mph62.0 mph+2.0 mph
65 mph67.1 mph+2.1 mph
70 mph72.3 mph+2.3 mph
75 mph77.4 mph+2.4 mph
80 mph82.6 mph+2.6 mph

Each size on its own

Questions

Which is bigger, 245/60R18 or 245/65R18?
245/65R18 is taller by 0.96 inches (30.54" vs 29.57"). 245/60R18 is the same width.
Can I replace 245/60R18 with 245/65R18?
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 245/65R18 change my speedometer?
When your speedometer reads 60 mph with 245/65R18 fitted (calibrated for 245/60R18), your real speed is 62.0 mph. Your odometer will under-count miles by about 3.3%.
Will 245/65R18 lift my vehicle?
Ride height changes by half the diameter difference: +0.48 inches of ground clearance at the axle.

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