275/35R18 vs 285/30R19

285/30R19 is 0.15 in (3.9 mm) taller than 275/35R18, a +0.60% diameter difference. With the speedometer set for 275/35R18, an indicated 60 mph is 60.4 mph on 285/30R19.

Is this a safe swap?

Diameter difference +0.60%: under 1%

By overall diameter alone, 285/30R19 is a near match for 275/35R18; the speedometer changes by less than 1%. 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.

275/35R18 vs 285/30R19 differences
Measurement	275/35R18	285/30R19	Difference	% diff
Overall diameter	25.58 in (649.7 mm)	25.73 in (653.6 mm)	+0.15 in (+3.9 mm)	+0.60%
Sidewall height	3.79 in (96.3 mm)	3.37 in (85.5 mm)	−0.42 in (−10.7 mm)	−11.17%
Section width	10.83 in (275.0 mm)	11.22 in (285.0 mm)	+0.39 in (+10.0 mm)	+3.64%
Circumference	80.36 in (2,041.1 mm)	80.84 in (2,053.3 mm)	+0.48 in (+12.3 mm)	+0.60%
Revolutions per mile	788	784	−5	−0.60%

True speed with the speedometer calibrated for 275/35R18
Indicated	Actual on 275/35R18	Actual on 285/30R19	Difference
30 mph	30.0 mph	30.2 mph	+0.2 mph
60 mph	60.0 mph	60.4 mph	+0.4 mph
75 mph	75.0 mph	75.5 mph	+0.5 mph

Ride-height change: 285/30R19 raises the vehicle by 0.08 in (1.9 mm) at the axle (half the +3.9 mm diameter difference).

285/30R19 is 0.15 in taller than 275/35R18 and 10 mm wider, a 0.60% difference in overall diameter.

With the speedometer calibrated for 275/35R18, an indicated 60 mph is actually 60.4 mph on 285/30R19, and revolutions per mile change from 788 to 784.

285/30R19 mounts on a 19-inch wheel, a plus-1 fitment from the 18-inch wheel of 275/35R18.

Size pages

Other comparisons with 275/35R18

Other comparisons with 285/30R19

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