275/70R17 vs 285/70R17

285/70R17 is 0.6" taller than 275/70R17 (1.7%)

Diameter difference+1.71%diameter 32.16" → 32.71"
275/70R17285/70R17
275/70R17285/70R17Difference
Overall diameter32.16"32.71"+0.55"
Section width10.83"11.22"+0.39"
Sidewall height7.58"7.85"+0.28"
Circumference101.0"102.8"+1.7"
Revolutions per mile627617−11
Wheel diameter17"17"±0"

Speedometer

ShowsActualDiff
30 mph30.5 mph+0.5
45 mph45.8 mph+0.8
60 mph61.0 mph+1.0
70 mph71.2 mph+1.2
80 mph81.4 mph+1.4

Gear ratio to match

CurrentEquivalent
3.423.48
3.553.61
3.733.79
4.104.17

285/70R17 is 0.55" taller than 275/70R17, a +1.71% change in diameter, inside the 3% range most shops treat as a safe swap.

Ground clearance changes by 0.28" (half the diameter change), and the tire needs 0.28" more room above it.

285/70R17 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 17" wheel; the sidewall is 0.28" taller on 285/70R17.

Details: 275/70R17 in inches · 285/70R17 in inches · change sizes in the calculator

FAQ

What is the difference between 275/70R17 and 285/70R17?

285/70R17 is 0.55" taller (+1.71%) and 0.39" wider than 275/70R17.

Will 285/70R17 change my speedometer?

Yes, by +1.71%. When the speedometer shows 60 mph you would be going 61.0 mph.

Can I replace 275/70R17 with 285/70R17?

Often yes: the diameter change of +1.7% is within the common 3% guideline. Check the load index, speed rating and clearance.