Tire Size Box

185/60R17 vs 185/70R17

185/70R17 compared with 185/60R17

+5.7% diameter, 0.0" width

185/70R17 is 27.20" tall vs 25.74". More than the 3% rule of thumb, so check carefully before switching.

25.7"17" rim4.4"7.3" wide
185/60R17 (solid) compared with 185/70R17 (dashed outline), drawn to scale

With 185/70R17 tires, when your speedometer says 60 mph you are really going

63.4 mph

185/70R17 is +1.46 inches (+5.7%) in overall diameter. That is more than the 3% most shops and makers recommend.

185/60R17185/70R17Difference%
Overall diameter25.74"27.20"+1.46"+5.7%
Section width7.28"7.28"0.00"0.0%
Sidewall height4.37"5.10"+0.73"+16.7%
Circumference80.87"85.44"+4.58"+5.7%
Revolutions per mile783.5741.6−42.0−5.4%

Speedometer difference

If your vehicle came with 185/60R17 and you fit 185/70R17, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.1 mph+1.1 mph
30 mph31.7 mph+1.7 mph
40 mph42.3 mph+2.3 mph
50 mph52.8 mph+2.8 mph
60 mph63.4 mph+3.4 mph
65 mph68.7 mph+3.7 mph
70 mph74.0 mph+4.0 mph
75 mph79.2 mph+4.2 mph
80 mph84.5 mph+4.5 mph

Each size on its own

Questions

Which is bigger, 185/60R17 or 185/70R17?
185/70R17 is taller by 1.46 inches (27.20" vs 25.74"). 185/60R17 is the same width.
Can I replace 185/60R17 with 185/70R17?
It is not recommended without checking carefully. The diameter difference is +5.7%, 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 185/70R17 change my speedometer?
When your speedometer reads 60 mph with 185/70R17 fitted (calibrated for 185/60R17), your real speed is 63.4 mph. Your odometer will under-count miles by about 5.7%.
Will 185/70R17 lift my vehicle?
Ride height changes by half the diameter difference: +0.73 inches of ground clearance at the axle.

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