TireSizesFinder

245/55R17 vs 245/45R19

245/45R19 is 0.07 in (1.8 mm) taller than 245/55R17, a +0.26% diameter difference. With the speedometer set for 245/55R17, an indicated 60 mph is 60.2 mph on 245/45R19.

Is this a safe swap?

Diameter difference +0.26%: under 1%

By overall diameter alone, 245/45R19 is a near match for 245/55R17; the speedometer changes by less than 1%. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 245/55R17 (27.61 in) vs 245/45R19 (27.68 in)245/55R1727.61 in × 9.65 in245/45R1927.68 in × 9.65 in
Side profile and tread width, drawn to the same scale.
245/55R17 vs 245/45R19 differences
Measurement245/55R17245/45R19Difference% diff
Overall diameter27.61 in (701.3 mm)27.68 in (703.1 mm)+0.07 in (+1.8 mm)+0.26%
Sidewall height5.31 in (134.8 mm)4.34 in (110.3 mm)−0.96 in (−24.5 mm)−18.18%
Section width9.65 in (245.0 mm)9.65 in (245.0 mm)0.00 in (0.0 mm)0.00%
Circumference86.74 in (2,203.2 mm)86.96 in (2,208.9 mm)+0.22 in (+5.7 mm)+0.26%
Revolutions per mile730729−2−0.26%
True speed with the speedometer calibrated for 245/55R17
IndicatedActual on 245/55R17Actual on 245/45R19Difference
30 mph30.0 mph30.1 mph+0.1 mph
60 mph60.0 mph60.2 mph+0.2 mph
75 mph75.0 mph75.2 mph+0.2 mph

Ride-height change: 245/45R19 raises the vehicle by 0.04 in (0.9 mm) at the axle (half the +1.8 mm diameter difference).

245/45R19 is 0.07 in taller than 245/55R17 and the same width, a 0.26% difference in overall diameter.

With the speedometer calibrated for 245/55R17, an indicated 60 mph is actually 60.2 mph on 245/45R19, and revolutions per mile change from 730 to 729.

245/45R19 mounts on a 19-inch wheel, a plus-2 fitment from the 17-inch wheel of 245/55R17.

Size pages

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Source: Calculated from standard tire geometry formulas. Verified . How these numbers are calculated.