275/40R17 vs 285/30R19

285/30R19 is 0.07 in (1.8 mm) taller than 275/40R17, a +0.28% diameter difference. With the speedometer set for 275/40R17, an indicated 60 mph is 60.2 mph on 285/30R19.

Is this a safe swap?

Diameter difference +0.28%: under 1%

By overall diameter alone, 285/30R19 is a near match for 275/40R17; 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.

275/40R17 vs 285/30R19 differences
Measurement	275/40R17	285/30R19	Difference	% diff
Overall diameter	25.66 in (651.8 mm)	25.73 in (653.6 mm)	+0.07 in (+1.8 mm)	+0.28%
Sidewall height	4.33 in (110.0 mm)	3.37 in (85.5 mm)	−0.96 in (−24.5 mm)	−22.27%
Section width	10.83 in (275.0 mm)	11.22 in (285.0 mm)	+0.39 in (+10.0 mm)	+3.64%
Circumference	80.62 in (2,047.7 mm)	80.84 in (2,053.3 mm)	+0.22 in (+5.7 mm)	+0.28%
Revolutions per mile	786	784	−2	−0.28%

True speed with the speedometer calibrated for 275/40R17
Indicated	Actual on 275/40R17	Actual on 285/30R19	Difference
30 mph	30.0 mph	30.1 mph	+0.1 mph
60 mph	60.0 mph	60.2 mph	+0.2 mph
75 mph	75.0 mph	75.2 mph	+0.2 mph

Ride-height change: 285/30R19 raises the vehicle by 0.04 in (0.9 mm) at the axle (half the +1.8 mm diameter difference).

285/30R19 is 0.07 in taller than 275/40R17 and 10 mm wider, a 0.28% difference in overall diameter.

With the speedometer calibrated for 275/40R17, an indicated 60 mph is actually 60.2 mph on 285/30R19, and revolutions per mile change from 786 to 784.

285/30R19 mounts on a 19-inch wheel, a plus-2 fitment from the 17-inch wheel of 275/40R17.

Size pages

Other comparisons with 275/40R17

Other comparisons with 285/30R19

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