Tire Size Box

295/55R20 vs 295/65R20

295/65R20 compared with 295/55R20

+7.1% diameter, 0.0" width

295/65R20 is 35.10" tall vs 32.78". More than the 3% rule of thumb, so check carefully before switching.

32.8"20" rim6.4"11.6" wide
295/55R20 (solid) compared with 295/65R20 (dashed outline), drawn to scale

With 295/65R20 tires, when your speedometer says 60 mph you are really going

64.3 mph

295/65R20 is +2.32 inches (+7.1%) in overall diameter. That is more than the 3% most shops and makers recommend.

295/55R20295/65R20Difference%
Overall diameter32.78"35.10"+2.32"+7.1%
Section width11.61"11.61"0.00"0.0%
Sidewall height6.39"7.55"+1.16"+18.2%
Circumference102.97"110.26"+7.30"+7.1%
Revolutions per mile615.3574.6−40.7−6.6%

Speedometer difference

If your vehicle came with 295/55R20 and you fit 295/65R20, 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 mph64.3 mph+4.3 mph
65 mph69.6 mph+4.6 mph
70 mph75.0 mph+5.0 mph
75 mph80.3 mph+5.3 mph
80 mph85.7 mph+5.7 mph

Each size on its own

Questions

Which is bigger, 295/55R20 or 295/65R20?
295/65R20 is taller by 2.32 inches (35.10" vs 32.78"). 295/55R20 is the same width.
Can I replace 295/55R20 with 295/65R20?
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 295/65R20 change my speedometer?
When your speedometer reads 60 mph with 295/65R20 fitted (calibrated for 295/55R20), your real speed is 64.3 mph. Your odometer will under-count miles by about 7.1%.
Will 295/65R20 lift my vehicle?
Ride height changes by half the diameter difference: +1.16 inches of ground clearance at the axle.

Other comparisons