Tire Size Box

245/60R15 vs 245/70R15

245/70R15 compared with 245/60R15

+7.3% diameter, 0.0" width

245/70R15 is 28.50" tall vs 26.57". More than the 3% rule of thumb, so check carefully before switching.

26.6"15" rim5.8"9.6" wide
245/60R15 (solid) compared with 245/70R15 (dashed outline), drawn to scale

With 245/70R15 tires, when your speedometer says 60 mph you are really going

64.4 mph

245/70R15 is +1.93 inches (+7.3%) in overall diameter. That is more than the 3% most shops and makers recommend.

245/60R15245/70R15Difference%
Overall diameter26.57"28.50"+1.93"+7.3%
Section width9.65"9.65"0.00"0.0%
Sidewall height5.79"6.75"+0.96"+16.7%
Circumference83.49"89.55"+6.06"+7.3%
Revolutions per mile758.9707.6−51.4−6.8%

Speedometer difference

If your vehicle came with 245/60R15 and you fit 245/70R15, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.5 mph+1.5 mph
30 mph32.2 mph+2.2 mph
40 mph42.9 mph+2.9 mph
50 mph53.6 mph+3.6 mph
60 mph64.4 mph+4.4 mph
65 mph69.7 mph+4.7 mph
70 mph75.1 mph+5.1 mph
75 mph80.4 mph+5.4 mph
80 mph85.8 mph+5.8 mph

Each size on its own

Questions

Which is bigger, 245/60R15 or 245/70R15?
245/70R15 is taller by 1.93 inches (28.50" vs 26.57"). 245/60R15 is the same width.
Can I replace 245/60R15 with 245/70R15?
It is not recommended without checking carefully. The diameter difference is +7.3%, 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 245/70R15 change my speedometer?
When your speedometer reads 60 mph with 245/70R15 fitted (calibrated for 245/60R15), your real speed is 64.4 mph. Your odometer will under-count miles by about 7.3%.
Will 245/70R15 lift my vehicle?
Ride height changes by half the diameter difference: +0.96 inches of ground clearance at the axle.

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