Tire Size Box

285/60R15 vs 285/70R15

285/70R15 compared with 285/60R15

+7.9% diameter, 0.0" width

285/70R15 is 30.71" tall vs 28.46". More than the 3% rule of thumb, so check carefully before switching.

28.5"15" rim6.7"11.2" wide
285/60R15 (solid) compared with 285/70R15 (dashed outline), drawn to scale

With 285/70R15 tires, when your speedometer says 60 mph you are really going

64.7 mph

285/70R15 is +2.24 inches (+7.9%) in overall diameter. That is more than the 3% most shops and makers recommend.

285/60R15285/70R15Difference%
Overall diameter28.46"30.71"+2.24"+7.9%
Section width11.22"11.22"0.00"0.0%
Sidewall height6.73"7.85"+1.12"+16.7%
Circumference89.42"96.47"+7.05"+7.9%
Revolutions per mile708.5656.8−51.8−7.3%

Speedometer difference

If your vehicle came with 285/60R15 and you fit 285/70R15, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.6 mph+1.6 mph
30 mph32.4 mph+2.4 mph
40 mph43.2 mph+3.2 mph
50 mph53.9 mph+3.9 mph
60 mph64.7 mph+4.7 mph
65 mph70.1 mph+5.1 mph
70 mph75.5 mph+5.5 mph
75 mph80.9 mph+5.9 mph
80 mph86.3 mph+6.3 mph

Each size on its own

Questions

Which is bigger, 285/60R15 or 285/70R15?
285/70R15 is taller by 2.24 inches (30.71" vs 28.46"). 285/60R15 is the same width.
Can I replace 285/60R15 with 285/70R15?
It is not recommended without checking carefully. The diameter difference is +7.9%, 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 285/70R15 change my speedometer?
When your speedometer reads 60 mph with 285/70R15 fitted (calibrated for 285/60R15), your real speed is 64.7 mph. Your odometer will under-count miles by about 7.9%.
Will 285/70R15 lift my vehicle?
Ride height changes by half the diameter difference: +1.12 inches of ground clearance at the axle.

Other comparisons