Tire Size Box

245/60R18 vs 265/60R18

265/60R18 compared with 245/60R18

+3.2% diameter, +0.8" width

265/60R18 is 30.52" 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 265/60R18 (dashed outline), drawn to scale

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

61.9 mph

265/60R18 is +0.94 inches (+3.2%) in overall diameter. That is more than the 3% most shops and makers recommend.

245/60R18265/60R18Difference%
Overall diameter29.57"30.52"+0.94"+3.2%
Section width9.65"10.43"+0.79"+8.2%
Sidewall height5.79"6.26"+0.47"+8.2%
Circumference92.91"95.88"+2.97"+3.2%
Revolutions per mile681.9660.8−21.1−3.1%

Speedometer difference

If your vehicle came with 245/60R18 and you fit 265/60R18, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.6 mph+0.6 mph
30 mph31.0 mph+1.0 mph
40 mph41.3 mph+1.3 mph
50 mph51.6 mph+1.6 mph
60 mph61.9 mph+1.9 mph
65 mph67.1 mph+2.1 mph
70 mph72.2 mph+2.2 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 265/60R18?
265/60R18 is taller by 0.94 inches (30.52" vs 29.57"). 265/60R18 is wider by 0.79 inches.
Can I replace 245/60R18 with 265/60R18?
It is not recommended without checking carefully. The diameter difference is +3.2%, 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 265/60R18 change my speedometer?
When your speedometer reads 60 mph with 265/60R18 fitted (calibrated for 245/60R18), your real speed is 61.9 mph. Your odometer will under-count miles by about 3.2%.
Will 265/60R18 lift my vehicle?
Ride height changes by half the diameter difference: +0.47 inches of ground clearance at the axle.

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