285/75R17 vs 295/70R18

295/70R18 is 0.43 in (10.9 mm) taller than 285/75R17, a +1.27% diameter difference. With the speedometer set for 285/75R17, an indicated 60 mph is 60.8 mph on 295/70R18.

Is this a safe swap?

Diameter difference +1.27%: within the ±3% guideline

By overall diameter alone, 295/70R18 falls inside the ±3% range commonly used as a guideline when replacing 285/75R17. 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.

285/75R17 vs 295/70R18 differences
Measurement	285/75R17	295/70R18	Difference	% diff
Overall diameter	33.83 in (859.3 mm)	34.26 in (870.2 mm)	+0.43 in (+10.9 mm)	+1.27%
Sidewall height	8.42 in (213.8 mm)	8.13 in (206.5 mm)	−0.29 in (−7.2 mm)	−3.39%
Section width	11.22 in (285.0 mm)	11.61 in (295.0 mm)	+0.39 in (+10.0 mm)	+3.51%
Circumference	106.28 in (2,699.6 mm)	107.63 in (2,733.8 mm)	+1.35 in (+34.2 mm)	+1.27%
Revolutions per mile	596	589	−7	−1.25%

True speed with the speedometer calibrated for 285/75R17
Indicated	Actual on 285/75R17	Actual on 295/70R18	Difference
30 mph	30.0 mph	30.4 mph	+0.4 mph
60 mph	60.0 mph	60.8 mph	+0.8 mph
75 mph	75.0 mph	76.0 mph	+1.0 mph

Ride-height change: 295/70R18 raises the vehicle by 0.21 in (5.5 mm) at the axle (half the +10.9 mm diameter difference).

295/70R18 is 0.43 in taller than 285/75R17 and 10 mm wider, a 1.27% difference in overall diameter.

With the speedometer calibrated for 285/75R17, an indicated 60 mph is actually 60.8 mph on 295/70R18, and revolutions per mile change from 596 to 589.

295/70R18 mounts on a 18-inch wheel, a plus-1 fitment from the 17-inch wheel of 285/75R17.

Size pages

Other comparisons with 285/75R17

Other comparisons with 295/70R18

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