TireSizesFinder

245/50R19 vs 325/30R21

325/30R21 is 0.03 in (0.8 mm) taller than 245/50R19, a +0.11% diameter difference. With the speedometer set for 245/50R19, an indicated 60 mph is 60.1 mph on 325/30R21.

Is this a safe swap?

Diameter difference +0.11%: under 1%

By overall diameter alone, 325/30R21 is a near match for 245/50R19; 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: 245/50R19 (28.65 in) vs 325/30R21 (28.68 in)245/50R1928.65 in × 9.65 in325/30R2128.68 in × 12.80 in
Side profile and tread width, drawn to the same scale.
245/50R19 vs 325/30R21 differences
Measurement245/50R19325/30R21Difference% diff
Overall diameter28.65 in (727.6 mm)28.68 in (728.4 mm)+0.03 in (+0.8 mm)+0.11%
Sidewall height4.82 in (122.5 mm)3.84 in (97.5 mm)−0.98 in (−25.0 mm)−20.41%
Section width9.65 in (245.0 mm)12.80 in (325.0 mm)+3.15 in (+80.0 mm)+32.65%
Circumference89.99 in (2,285.8 mm)90.09 in (2,288.3 mm)+0.10 in (+2.5 mm)+0.11%
Revolutions per mile704703−1−0.11%
True speed with the speedometer calibrated for 245/50R19
IndicatedActual on 245/50R19Actual on 325/30R21Difference
30 mph30.0 mph30.0 mph0.0 mph
60 mph60.0 mph60.1 mph+0.1 mph
75 mph75.0 mph75.1 mph+0.1 mph

Ride-height change: 325/30R21 raises the vehicle by 0.02 in (0.4 mm) at the axle (half the +0.8 mm diameter difference).

325/30R21 is 0.03 in taller than 245/50R19 and 80 mm wider, a 0.11% difference in overall diameter.

With the speedometer calibrated for 245/50R19, an indicated 60 mph is actually 60.1 mph on 325/30R21, and revolutions per mile change from 704 to 703.

325/30R21 mounts on a 21-inch wheel, a plus-2 fitment from the 19-inch wheel of 245/50R19.

Size pages

Other comparisons with 245/50R19

Other comparisons with 325/30R21

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