205/50R17 vs 245/30R19

245/30R19 is 0.28 in (7.2 mm) shorter than 205/50R17, a −1.13% diameter difference. With the speedometer set for 205/50R17, an indicated 60 mph is 59.3 mph on 245/30R19.

Is this a safe swap?

Diameter difference −1.13%: within the ±3% guideline

By overall diameter alone, 245/30R19 falls inside the ±3% range commonly used as a guideline when replacing 205/50R17. 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.

205/50R17 vs 245/30R19 differences
Measurement	205/50R17	245/30R19	Difference	% diff
Overall diameter	25.07 in (636.8 mm)	24.79 in (629.6 mm)	−0.28 in (−7.2 mm)	−1.13%
Sidewall height	4.04 in (102.5 mm)	2.89 in (73.5 mm)	−1.14 in (−29.0 mm)	−28.29%
Section width	8.07 in (205.0 mm)	9.65 in (245.0 mm)	+1.57 in (+40.0 mm)	+19.51%
Circumference	78.76 in (2,000.6 mm)	77.87 in (1,977.9 mm)	−0.89 in (−22.6 mm)	−1.13%
Revolutions per mile	804	814	+9	+1.14%

True speed with the speedometer calibrated for 205/50R17
Indicated	Actual on 205/50R17	Actual on 245/30R19	Difference
30 mph	30.0 mph	29.7 mph	−0.3 mph
60 mph	60.0 mph	59.3 mph	−0.7 mph
75 mph	75.0 mph	74.2 mph	−0.8 mph

Ride-height change: 245/30R19 lowers the vehicle by 0.14 in (3.6 mm) at the axle (half the −7.2 mm diameter difference).

245/30R19 is 0.28 in shorter than 205/50R17 and 40 mm wider, a 1.13% difference in overall diameter.

With the speedometer calibrated for 205/50R17, an indicated 60 mph is actually 59.3 mph on 245/30R19, and revolutions per mile change from 804 to 814.

245/30R19 mounts on a 19-inch wheel, a plus-2 fitment from the 17-inch wheel of 205/50R17.

Size pages

Other comparisons with 205/50R17

Other comparisons with 245/30R19

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