235/50R19 vs 295/30R21

295/30R21 is 0.28 in (7.2 mm) shorter than 235/50R19, a −1.00% diameter difference. With the speedometer set for 235/50R19, an indicated 60 mph is 59.4 mph on 295/30R21.

Is this a safe swap?

Diameter difference −1.00%: within the ±3% guideline

By overall diameter alone, 295/30R21 falls inside the ±3% range commonly used as a guideline when replacing 235/50R19. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 235/50R19 (28.25 in) vs 295/30R21 (27.97 in)235/50R1928.25 in × 9.25 in295/30R2127.97 in × 11.61 in
Side profile and tread width, drawn to the same scale.
235/50R19 vs 295/30R21 differences
Measurement235/50R19295/30R21Difference% diff
Overall diameter28.25 in (717.6 mm)27.97 in (710.4 mm)−0.28 in (−7.2 mm)−1.00%
Sidewall height4.63 in (117.5 mm)3.48 in (88.5 mm)−1.14 in (−29.0 mm)−24.68%
Section width9.25 in (235.0 mm)11.61 in (295.0 mm)+2.36 in (+60.0 mm)+25.53%
Circumference88.76 in (2,254.4 mm)87.87 in (2,231.8 mm)−0.89 in (−22.6 mm)−1.00%
Revolutions per mile714721+7+1.01%
True speed with the speedometer calibrated for 235/50R19
IndicatedActual on 235/50R19Actual on 295/30R21Difference
30 mph30.0 mph29.7 mph−0.3 mph
60 mph60.0 mph59.4 mph−0.6 mph
75 mph75.0 mph74.2 mph−0.8 mph

Ride-height change: 295/30R21 lowers the vehicle by 0.14 in (3.6 mm) at the axle (half the −7.2 mm diameter difference).

295/30R21 is 0.28 in shorter than 235/50R19 and 60 mm wider, a 1.00% difference in overall diameter.

With the speedometer calibrated for 235/50R19, an indicated 60 mph is actually 59.4 mph on 295/30R21, and revolutions per mile change from 714 to 721.

295/30R21 mounts on a 21-inch wheel, a plus-2 fitment from the 19-inch wheel of 235/50R19.

Size pages

Other comparisons with 235/50R19

Other comparisons with 295/30R21

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