255/80R17 vs 285/75R17

285/75R17 is 0.77 in (19.5 mm) taller than 255/80R17, a +2.32% diameter difference. With the speedometer set for 255/80R17, an indicated 60 mph is 61.4 mph on 285/75R17.

Is this a safe swap?

Diameter difference +2.32%: within the ±3% guideline

By overall diameter alone, 285/75R17 falls inside the ±3% range commonly used as a guideline when replacing 255/80R17. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

Side profile and tread width, drawn to the same scale.

255/80R17 vs 285/75R17 differences
Measurement	255/80R17	285/75R17	Difference	% diff
Overall diameter	33.06 in (839.8 mm)	33.83 in (859.3 mm)	+0.77 in (+19.5 mm)	+2.32%
Sidewall height	8.03 in (204.0 mm)	8.42 in (213.8 mm)	+0.38 in (+9.8 mm)	+4.78%
Section width	10.04 in (255.0 mm)	11.22 in (285.0 mm)	+1.18 in (+30.0 mm)	+11.76%
Circumference	103.87 in (2,638.3 mm)	106.28 in (2,699.6 mm)	+2.41 in (+61.3 mm)	+2.32%
Revolutions per mile	610	596	−14	−2.27%

True speed with the speedometer calibrated for 255/80R17
Indicated	Actual on 255/80R17	Actual on 285/75R17	Difference
30 mph	30.0 mph	30.7 mph	+0.7 mph
60 mph	60.0 mph	61.4 mph	+1.4 mph
75 mph	75.0 mph	76.7 mph	+1.7 mph

Ride-height change: 285/75R17 raises the vehicle by 0.38 in (9.8 mm) at the axle (half the +19.5 mm diameter difference).

285/75R17 is 0.77 in taller than 255/80R17 and 30 mm wider, a 2.32% difference in overall diameter.

With the speedometer calibrated for 255/80R17, an indicated 60 mph is actually 61.4 mph on 285/75R17, and revolutions per mile change from 610 to 596.

Both sizes mount on 17-inch wheels.

Size pages

Other comparisons with 255/80R17

Other comparisons with 285/75R17

Source: Calculated from standard tire geometry formulas. Verified 2026-09-27. How these numbers are calculated.