TireSizesFinder

305/30R19 vs 225/35R20

225/35R20 is 0.00 in (0.1 mm) shorter than 305/30R19, a −0.02% diameter difference. With the speedometer set for 305/30R19, an indicated 60 mph is 60.0 mph on 225/35R20.

Is this a safe swap?

Diameter difference −0.02%: under 1%

By overall diameter alone, 225/35R20 is a near match for 305/30R19; 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: 305/30R19 (26.20 in) vs 225/35R20 (26.20 in)305/30R1926.20 in × 12.01 in225/35R2026.20 in × 8.86 in
Side profile and tread width, drawn to the same scale.
305/30R19 vs 225/35R20 differences
Measurement305/30R19225/35R20Difference% diff
Overall diameter26.20 in (665.6 mm)26.20 in (665.5 mm)0.00 in (−0.1 mm)−0.02%
Sidewall height3.60 in (91.5 mm)3.10 in (78.8 mm)−0.50 in (−12.7 mm)−13.93%
Section width12.01 in (305.0 mm)8.86 in (225.0 mm)−3.15 in (−80.0 mm)−26.23%
Circumference82.32 in (2,091.0 mm)82.31 in (2,090.7 mm)−0.01 in (−0.3 mm)−0.02%
Revolutions per mile7707700+0.02%
True speed with the speedometer calibrated for 305/30R19
IndicatedActual on 305/30R19Actual on 225/35R20Difference
30 mph30.0 mph30.0 mph0.0 mph
60 mph60.0 mph60.0 mph0.0 mph
75 mph75.0 mph75.0 mph0.0 mph

Ride-height change: 225/35R20 does not change the vehicle at the axle (half the −0.1 mm diameter difference).

225/35R20 is the same height as 305/30R19 and 80 mm narrower, a 0.02% difference in overall diameter.

With the speedometer calibrated for 305/30R19, an indicated 60 mph is actually 60.0 mph on 225/35R20, and revolutions per mile change from 770 to 770.

225/35R20 mounts on a 20-inch wheel, a plus-1 fitment from the 19-inch wheel of 305/30R19.

Size pages

Other comparisons with 305/30R19

Other comparisons with 225/35R20

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