TireSizesFinder

235/50R17 vs 305/30R19

305/30R19 is 0.05 in (1.2 mm) shorter than 235/50R17, a −0.18% diameter difference. With the speedometer set for 235/50R17, an indicated 60 mph is 59.9 mph on 305/30R19.

Is this a safe swap?

Diameter difference −0.18%: under 1%

By overall diameter alone, 305/30R19 is a near match for 235/50R17; 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: 235/50R17 (26.25 in) vs 305/30R19 (26.20 in)235/50R1726.25 in × 9.25 in305/30R1926.20 in × 12.01 in
Side profile and tread width, drawn to the same scale.
235/50R17 vs 305/30R19 differences
Measurement235/50R17305/30R19Difference% diff
Overall diameter26.25 in (666.8 mm)26.20 in (665.6 mm)−0.05 in (−1.2 mm)−0.18%
Sidewall height4.63 in (117.5 mm)3.60 in (91.5 mm)−1.02 in (−26.0 mm)−22.13%
Section width9.25 in (235.0 mm)12.01 in (305.0 mm)+2.76 in (+70.0 mm)+29.79%
Circumference82.47 in (2,094.8 mm)82.32 in (2,091.0 mm)−0.15 in (−3.8 mm)−0.18%
Revolutions per mile768770+1+0.18%
True speed with the speedometer calibrated for 235/50R17
IndicatedActual on 235/50R17Actual on 305/30R19Difference
30 mph30.0 mph29.9 mph−0.1 mph
60 mph60.0 mph59.9 mph−0.1 mph
75 mph75.0 mph74.9 mph−0.1 mph

Ride-height change: 305/30R19 lowers the vehicle by 0.02 in (0.6 mm) at the axle (half the −1.2 mm diameter difference).

305/30R19 is 0.05 in shorter than 235/50R17 and 70 mm wider, a 0.18% difference in overall diameter.

With the speedometer calibrated for 235/50R17, an indicated 60 mph is actually 59.9 mph on 305/30R19, and revolutions per mile change from 768 to 770.

305/30R19 mounts on a 19-inch wheel, a plus-2 fitment from the 17-inch wheel of 235/50R17.

Size pages

Other comparisons with 235/50R17

Other comparisons with 305/30R19

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