Tire Size Box

275/60R15 vs 275/70R15

275/70R15 compared with 275/60R15

+7.7% diameter, 0.0" width

275/70R15 is 30.16" tall vs 27.99". More than the 3% rule of thumb, so check carefully before switching.

28.0"15" rim6.5"10.8" wide
275/60R15 (solid) compared with 275/70R15 (dashed outline), drawn to scale

With 275/70R15 tires, when your speedometer says 60 mph you are really going

64.6 mph

275/70R15 is +2.17 inches (+7.7%) in overall diameter. That is more than the 3% most shops and makers recommend.

275/60R15275/70R15Difference%
Overall diameter27.99"30.16"+2.17"+7.7%
Section width10.83"10.83"0.00"0.0%
Sidewall height6.50"7.58"+1.08"+16.7%
Circumference87.94"94.74"+6.80"+7.7%
Revolutions per mile720.5668.8−51.7−7.2%

Speedometer difference

If your vehicle came with 275/60R15 and you fit 275/70R15, 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, 275/60R15 or 275/70R15?
275/70R15 is taller by 2.17 inches (30.16" vs 27.99"). 275/60R15 is the same width.
Can I replace 275/60R15 with 275/70R15?
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 275/70R15 change my speedometer?
When your speedometer reads 60 mph with 275/70R15 fitted (calibrated for 275/60R15), your real speed is 64.6 mph. Your odometer will under-count miles by about 7.7%.
Will 275/70R15 lift my vehicle?
Ride height changes by half the diameter difference: +1.08 inches of ground clearance at the axle.

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