Tire Size Box

235/55R14 vs 235/65R14

235/65R14 compared with 235/55R14

+7.7% diameter, 0.0" width

235/65R14 is 26.03" tall vs 24.18". More than the 3% rule of thumb, so check carefully before switching.

24.2"14" rim5.1"9.3" wide
235/55R14 (solid) compared with 235/65R14 (dashed outline), drawn to scale

With 235/65R14 tires, when your speedometer says 60 mph you are really going

64.6 mph

235/65R14 is +1.85 inches (+7.7%) in overall diameter. That is more than the 3% most shops and makers recommend.

235/55R14235/65R14Difference%
Overall diameter24.18"26.03"+1.85"+7.7%
Section width9.25"9.25"0.00"0.0%
Sidewall height5.09"6.01"+0.93"+18.2%
Circumference75.95"81.77"+5.81"+7.7%
Revolutions per mile834.2774.9−59.3−7.1%

Speedometer difference

If your vehicle came with 235/55R14 and you fit 235/65R14, 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 mph53.8 mph+3.8 mph
60 mph64.6 mph+4.6 mph
65 mph70.0 mph+5.0 mph
70 mph75.4 mph+5.4 mph
75 mph80.7 mph+5.7 mph
80 mph86.1 mph+6.1 mph

Each size on its own

Questions

Which is bigger, 235/55R14 or 235/65R14?
235/65R14 is taller by 1.85 inches (26.03" vs 24.18"). 235/55R14 is the same width.
Can I replace 235/55R14 with 235/65R14?
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 235/65R14 change my speedometer?
When your speedometer reads 60 mph with 235/65R14 fitted (calibrated for 235/55R14), your real speed is 64.6 mph. Your odometer will under-count miles by about 7.7%.
Will 235/65R14 lift my vehicle?
Ride height changes by half the diameter difference: +0.93 inches of ground clearance at the axle.

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