Tire Size Box

225/60R18 vs 225/70R18

225/70R18 compared with 225/60R18

+6.2% diameter, 0.0" width

225/70R18 is 30.40" tall vs 28.63". More than the 3% rule of thumb, so check carefully before switching.

28.6"18" rim5.3"8.9" wide
225/60R18 (solid) compared with 225/70R18 (dashed outline), drawn to scale

With 225/70R18 tires, when your speedometer says 60 mph you are really going

63.7 mph

225/70R18 is +1.77 inches (+6.2%) in overall diameter. That is more than the 3% most shops and makers recommend.

225/60R18225/70R18Difference%
Overall diameter28.63"30.40"+1.77"+6.2%
Section width8.86"8.86"0.00"0.0%
Sidewall height5.31"6.20"+0.89"+16.7%
Circumference89.94"95.51"+5.57"+6.2%
Revolutions per mile704.4663.4−41.1−5.8%

Speedometer difference

If your vehicle came with 225/60R18 and you fit 225/70R18, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.2 mph+1.2 mph
30 mph31.9 mph+1.9 mph
40 mph42.5 mph+2.5 mph
50 mph53.1 mph+3.1 mph
60 mph63.7 mph+3.7 mph
65 mph69.0 mph+4.0 mph
70 mph74.3 mph+4.3 mph
75 mph79.6 mph+4.6 mph
80 mph85.0 mph+5.0 mph

Each size on its own

Questions

Which is bigger, 225/60R18 or 225/70R18?
225/70R18 is taller by 1.77 inches (30.40" vs 28.63"). 225/60R18 is the same width.
Can I replace 225/60R18 with 225/70R18?
It is not recommended without checking carefully. The diameter difference is +6.2%, 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 225/70R18 change my speedometer?
When your speedometer reads 60 mph with 225/70R18 fitted (calibrated for 225/60R18), your real speed is 63.7 mph. Your odometer will under-count miles by about 6.2%.
Will 225/70R18 lift my vehicle?
Ride height changes by half the diameter difference: +0.89 inches of ground clearance at the axle.

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