Tire Size Box

235/55R16 vs 235/65R16

235/65R16 compared with 235/55R16

+7.1% diameter, 0.0" width

235/65R16 is 28.03" tall vs 26.18". More than the 3% rule of thumb, so check carefully before switching.

26.2"16" rim5.1"9.3" wide
235/55R16 (solid) compared with 235/65R16 (dashed outline), drawn to scale

With 235/65R16 tires, when your speedometer says 60 mph you are really going

64.2 mph

235/65R16 is +1.85 inches (+7.1%) in overall diameter. That is more than the 3% most shops and makers recommend.

235/55R16235/65R16Difference%
Overall diameter26.18"28.03"+1.85"+7.1%
Section width9.25"9.25"0.00"0.0%
Sidewall height5.09"6.01"+0.93"+18.2%
Circumference82.24"88.05"+5.81"+7.1%
Revolutions per mile770.4719.6−50.9−6.6%

Speedometer difference

If your vehicle came with 235/55R16 and you fit 235/65R16, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.4 mph+1.4 mph
30 mph32.1 mph+2.1 mph
40 mph42.8 mph+2.8 mph
50 mph53.5 mph+3.5 mph
60 mph64.2 mph+4.2 mph
65 mph69.6 mph+4.6 mph
70 mph74.9 mph+4.9 mph
75 mph80.3 mph+5.3 mph
80 mph85.7 mph+5.7 mph

Each size on its own

Questions

Which is bigger, 235/55R16 or 235/65R16?
235/65R16 is taller by 1.85 inches (28.03" vs 26.18"). 235/55R16 is the same width.
Can I replace 235/55R16 with 235/65R16?
It is not recommended without checking carefully. The diameter difference is +7.1%, 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 235/65R16 change my speedometer?
When your speedometer reads 60 mph with 235/65R16 fitted (calibrated for 235/55R16), your real speed is 64.2 mph. Your odometer will under-count miles by about 7.1%.
Will 235/65R16 lift my vehicle?
Ride height changes by half the diameter difference: +0.93 inches of ground clearance at the axle.

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