305/75R16 vs 285/75R16

305/75R16 is 1.2" taller than 285/75R16 (3.5%)

Diameter difference−3.47%diameter 34.01" → 32.83"
305/75R16285/75R16
305/75R16285/75R16Difference
Overall diameter34.01"32.83"−1.18"
Section width12.01"11.22"−0.79"
Sidewall height9.01"8.42"−0.59"
Circumference106.9"103.1"−3.7"
Revolutions per mile593614+21
Wheel diameter16"16"±0"

Speedometer

ShowsActualDiff
30 mph29.0 mph−1.0
45 mph43.4 mph−1.6
60 mph57.9 mph−2.1
70 mph67.6 mph−2.4
80 mph77.2 mph−2.8

Gear ratio to match

CurrentEquivalent
3.423.30
3.553.43
3.733.60
4.103.96

285/75R16 is 1.18" shorter than 305/75R16, a −3.47% change in diameter. That is more than the 3% many tire shops use as a limit, so plan on recalibrating the speedometer and checking ABS and stability control.

Ground clearance changes by 0.59" (half the diameter change), and the tire needs 0.59" less room above it.

305/75R16 is 0.79" wider. On the same wheel offset about half of that, 0.39", moves toward the suspension and half toward the fender.

Both fit a 16" wheel; the sidewall is 0.59" shorter on 285/75R16.

Details: 305/75R16 in inches · 285/75R16 in inches · change sizes in the calculator

FAQ

What is the difference between 305/75R16 and 285/75R16?

285/75R16 is 1.18" shorter (−3.47%) and 0.79" narrower than 305/75R16.

Will 285/75R16 change my speedometer?

Yes, by −3.47%. When the speedometer shows 60 mph you would be going 57.9 mph.

Can I replace 305/75R16 with 285/75R16?

It is a −3.5% diameter change, larger than the common 3% guideline, so check clearance and plan to recalibrate.