Tire Size Box

255/60R14 vs 255/70R14

255/70R14 compared with 255/60R14

+7.7% diameter, 0.0" width

255/70R14 is 28.06" tall vs 26.05". More than the 3% rule of thumb, so check carefully before switching.

26.0"14" rim6.0"10.0" wide
255/60R14 (solid) compared with 255/70R14 (dashed outline), drawn to scale

With 255/70R14 tires, when your speedometer says 60 mph you are really going

64.6 mph

255/70R14 is +2.01 inches (+7.7%) in overall diameter. That is more than the 3% most shops and makers recommend.

255/60R14255/70R14Difference%
Overall diameter26.05"28.06"+2.01"+7.7%
Section width10.04"10.04"0.00"0.0%
Sidewall height6.02"7.03"+1.00"+16.7%
Circumference81.83"88.14"+6.31"+7.7%
Revolutions per mile774.3718.9−55.4−7.2%

Speedometer difference

If your vehicle came with 255/60R14 and you fit 255/70R14, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.5 mph+1.5 mph
30 mph32.3 mph+2.3 mph
40 mph43.1 mph+3.1 mph
50 mph53.9 mph+3.9 mph
60 mph64.6 mph+4.6 mph
65 mph70.0 mph+5.0 mph
70 mph75.4 mph+5.4 mph
75 mph80.8 mph+5.8 mph
80 mph86.2 mph+6.2 mph

Each size on its own

Questions

Which is bigger, 255/60R14 or 255/70R14?
255/70R14 is taller by 2.01 inches (28.06" vs 26.05"). 255/60R14 is the same width.
Can I replace 255/60R14 with 255/70R14?
It is not recommended without checking carefully. The diameter difference is +7.7%, 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 255/70R14 change my speedometer?
When your speedometer reads 60 mph with 255/70R14 fitted (calibrated for 255/60R14), your real speed is 64.6 mph. Your odometer will under-count miles by about 7.7%.
Will 255/70R14 lift my vehicle?
Ride height changes by half the diameter difference: +1.00 inches of ground clearance at the axle.

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