245/45R17 vs 275/30R19

275/30R19 is 0.19 in (4.7 mm) shorter than 245/45R17, a −0.72% diameter difference. With the speedometer set for 245/45R17, an indicated 60 mph is 59.6 mph on 275/30R19.

Is this a safe swap?

Diameter difference −0.72%: under 1%

By overall diameter alone, 275/30R19 is a near match for 245/45R17; 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.

245/45R17 vs 275/30R19 differences
Measurement	245/45R17	275/30R19	Difference	% diff
Overall diameter	25.68 in (652.3 mm)	25.50 in (647.6 mm)	−0.19 in (−4.7 mm)	−0.72%
Sidewall height	4.34 in (110.3 mm)	3.25 in (82.5 mm)	−1.09 in (−27.7 mm)	−25.17%
Section width	9.65 in (245.0 mm)	10.83 in (275.0 mm)	+1.18 in (+30.0 mm)	+12.24%
Circumference	80.68 in (2,049.3 mm)	80.10 in (2,034.5 mm)	−0.58 in (−14.8 mm)	−0.72%
Revolutions per mile	785	791	+6	+0.73%

True speed with the speedometer calibrated for 245/45R17
Indicated	Actual on 245/45R17	Actual on 275/30R19	Difference
30 mph	30.0 mph	29.8 mph	−0.2 mph
60 mph	60.0 mph	59.6 mph	−0.4 mph
75 mph	75.0 mph	74.5 mph	−0.5 mph

Ride-height change: 275/30R19 lowers the vehicle by 0.09 in (2.4 mm) at the axle (half the −4.7 mm diameter difference).

275/30R19 is 0.19 in shorter than 245/45R17 and 30 mm wider, a 0.72% difference in overall diameter.

With the speedometer calibrated for 245/45R17, an indicated 60 mph is actually 59.6 mph on 275/30R19, and revolutions per mile change from 785 to 791.

275/30R19 mounts on a 19-inch wheel, a plus-2 fitment from the 17-inch wheel of 245/45R17.

Size pages

Other comparisons with 245/45R17

Other comparisons with 275/30R19

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