Tire Size Box

275/60R20 vs 275/65R20

275/65R20 compared with 275/60R20

+3.3% diameter, 0.0" width

275/65R20 is 34.07" tall vs 32.99". More than the 3% rule of thumb, so check carefully before switching.

33.0"20" rim6.5"10.8" wide
275/60R20 (solid) compared with 275/65R20 (dashed outline), drawn to scale

With 275/65R20 tires, when your speedometer says 60 mph you are really going

62.0 mph

275/65R20 is +1.08 inches (+3.3%) in overall diameter. That is more than the 3% most shops and makers recommend.

275/60R20275/65R20Difference%
Overall diameter32.99"34.07"+1.08"+3.3%
Section width10.83"10.83"0.00"0.0%
Sidewall height6.50"7.04"+0.54"+8.3%
Circumference103.65"107.05"+3.40"+3.3%
Revolutions per mile611.3591.9−19.4−3.2%

Speedometer difference

If your vehicle came with 275/60R20 and you fit 275/65R20, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.7 mph+0.7 mph
30 mph31.0 mph+1.0 mph
40 mph41.3 mph+1.3 mph
50 mph51.6 mph+1.6 mph
60 mph62.0 mph+2.0 mph
65 mph67.1 mph+2.1 mph
70 mph72.3 mph+2.3 mph
75 mph77.5 mph+2.5 mph
80 mph82.6 mph+2.6 mph

Each size on its own

Questions

Which is bigger, 275/60R20 or 275/65R20?
275/65R20 is taller by 1.08 inches (34.07" vs 32.99"). 275/60R20 is the same width.
Can I replace 275/60R20 with 275/65R20?
It is not recommended without checking carefully. The diameter difference is +3.3%, 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 275/65R20 change my speedometer?
When your speedometer reads 60 mph with 275/65R20 fitted (calibrated for 275/60R20), your real speed is 62.0 mph. Your odometer will under-count miles by about 3.3%.
Will 275/65R20 lift my vehicle?
Ride height changes by half the diameter difference: +0.54 inches of ground clearance at the axle.

Other comparisons