Tire Size Box

235/60R17 vs 235/70R17

235/70R17 compared with 235/60R17

+6.6% diameter, 0.0" width

235/70R17 is 29.95" tall vs 28.10". More than the 3% rule of thumb, so check carefully before switching.

28.1"17" rim5.6"9.3" wide
235/60R17 (solid) compared with 235/70R17 (dashed outline), drawn to scale

With 235/70R17 tires, when your speedometer says 60 mph you are really going

64.0 mph

235/70R17 is +1.85 inches (+6.6%) in overall diameter. That is more than the 3% most shops and makers recommend.

235/60R17235/70R17Difference%
Overall diameter28.10"29.95"+1.85"+6.6%
Section width9.25"9.25"0.00"0.0%
Sidewall height5.55"6.48"+0.93"+16.7%
Circumference88.29"94.10"+5.81"+6.6%
Revolutions per mile717.7673.3−44.3−6.2%

Speedometer difference

If your vehicle came with 235/60R17 and you fit 235/70R17, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.3 mph+1.3 mph
30 mph32.0 mph+2.0 mph
40 mph42.6 mph+2.6 mph
50 mph53.3 mph+3.3 mph
60 mph64.0 mph+4.0 mph
65 mph69.3 mph+4.3 mph
70 mph74.6 mph+4.6 mph
75 mph79.9 mph+4.9 mph
80 mph85.3 mph+5.3 mph

Each size on its own

Questions

Which is bigger, 235/60R17 or 235/70R17?
235/70R17 is taller by 1.85 inches (29.95" vs 28.10"). 235/60R17 is the same width.
Can I replace 235/60R17 with 235/70R17?
It is not recommended without checking carefully. The diameter difference is +6.6%, 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 235/70R17 change my speedometer?
When your speedometer reads 60 mph with 235/70R17 fitted (calibrated for 235/60R17), your real speed is 64.0 mph. Your odometer will under-count miles by about 6.6%.
Will 235/70R17 lift my vehicle?
Ride height changes by half the diameter difference: +0.93 inches of ground clearance at the axle.

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