275/65R20 vs 285/65R20

285/65R20 is 0.5" taller than 275/65R20 (1.5%)

Diameter difference+1.50%diameter 34.07" → 34.59"
275/65R20285/65R20
275/65R20285/65R20Difference
Overall diameter34.07"34.59"+0.51"
Section width10.83"11.22"+0.39"
Sidewall height7.04"7.29"+0.26"
Circumference107.0"108.7"+1.6"
Revolutions per mile592583−9
Wheel diameter20"20"±0"

Speedometer

ShowsActualDiff
30 mph30.5 mph+0.5
45 mph45.7 mph+0.7
60 mph60.9 mph+0.9
70 mph71.1 mph+1.1
80 mph81.2 mph+1.2

Gear ratio to match

CurrentEquivalent
3.423.47
3.553.60
3.733.79
4.104.16

285/65R20 is 0.51" taller than 275/65R20, a +1.50% change in diameter, inside the 3% range most shops treat as a safe swap.

Ground clearance changes by 0.26" (half the diameter change), and the tire needs 0.26" more room above it.

285/65R20 is 0.39" wider. On the same wheel offset about half of that, 0.20", moves toward the suspension and half toward the fender.

Both fit a 20" wheel; the sidewall is 0.26" taller on 285/65R20.

Details: 275/65R20 in inches · 285/65R20 in inches · change sizes in the calculator

FAQ

What is the difference between 275/65R20 and 285/65R20?

285/65R20 is 0.51" taller (+1.50%) and 0.39" wider than 275/65R20.

Will 285/65R20 change my speedometer?

Yes, by +1.50%. When the speedometer shows 60 mph you would be going 60.9 mph.

Can I replace 275/65R20 with 285/65R20?

Often yes: the diameter change of +1.5% is within the common 3% guideline. Check the load index, speed rating and clearance.