Tire Size Box

245/55R14 vs 245/65R14

245/65R14 compared with 245/55R14

+7.8% diameter, 0.0" width

245/65R14 is 26.54" tall vs 24.61". More than the 3% rule of thumb, so check carefully before switching.

24.6"14" rim5.3"9.6" wide
245/55R14 (solid) compared with 245/65R14 (dashed outline), drawn to scale

With 245/65R14 tires, when your speedometer says 60 mph you are really going

64.7 mph

245/65R14 is +1.93 inches (+7.8%) in overall diameter. That is more than the 3% most shops and makers recommend.

245/55R14245/65R14Difference%
Overall diameter24.61"26.54"+1.93"+7.8%
Section width9.65"9.65"0.00"0.0%
Sidewall height5.31"6.27"+0.96"+18.2%
Circumference77.32"83.38"+6.06"+7.8%
Revolutions per mile819.5759.9−59.6−7.3%

Speedometer difference

If your vehicle came with 245/55R14 and you fit 245/65R14, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.6 mph+1.6 mph
30 mph32.4 mph+2.4 mph
40 mph43.1 mph+3.1 mph
50 mph53.9 mph+3.9 mph
60 mph64.7 mph+4.7 mph
65 mph70.1 mph+5.1 mph
70 mph75.5 mph+5.5 mph
75 mph80.9 mph+5.9 mph
80 mph86.3 mph+6.3 mph

Each size on its own

Questions

Which is bigger, 245/55R14 or 245/65R14?
245/65R14 is taller by 1.93 inches (26.54" vs 24.61"). 245/55R14 is the same width.
Can I replace 245/55R14 with 245/65R14?
It is not recommended without checking carefully. The diameter difference is +7.8%, 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 245/65R14 change my speedometer?
When your speedometer reads 60 mph with 245/65R14 fitted (calibrated for 245/55R14), your real speed is 64.7 mph. Your odometer will under-count miles by about 7.8%.
Will 245/65R14 lift my vehicle?
Ride height changes by half the diameter difference: +0.96 inches of ground clearance at the axle.

Other comparisons