TireSizesFinder

285/30R19 vs 305/30R19

305/30R19 is 0.47 in (12.0 mm) taller than 285/30R19, a +1.84% diameter difference. With the speedometer set for 285/30R19, an indicated 60 mph is 61.1 mph on 305/30R19.

Is this a safe swap?

Diameter difference +1.84%: within the ±3% guideline

By overall diameter alone, 305/30R19 falls inside the ±3% range commonly used as a guideline when replacing 285/30R19. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 285/30R19 (25.73 in) vs 305/30R19 (26.20 in)285/30R1925.73 in × 11.22 in305/30R1926.20 in × 12.01 in
Side profile and tread width, drawn to the same scale.
285/30R19 vs 305/30R19 differences
Measurement285/30R19305/30R19Difference% diff
Overall diameter25.73 in (653.6 mm)26.20 in (665.6 mm)+0.47 in (+12.0 mm)+1.84%
Sidewall height3.37 in (85.5 mm)3.60 in (91.5 mm)+0.24 in (+6.0 mm)+7.02%
Section width11.22 in (285.0 mm)12.01 in (305.0 mm)+0.79 in (+20.0 mm)+7.02%
Circumference80.84 in (2,053.3 mm)82.32 in (2,091.0 mm)+1.48 in (+37.7 mm)+1.84%
Revolutions per mile784770−14−1.80%
True speed with the speedometer calibrated for 285/30R19
IndicatedActual on 285/30R19Actual on 305/30R19Difference
30 mph30.0 mph30.6 mph+0.6 mph
60 mph60.0 mph61.1 mph+1.1 mph
75 mph75.0 mph76.4 mph+1.4 mph

Ride-height change: 305/30R19 raises the vehicle by 0.24 in (6.0 mm) at the axle (half the +12.0 mm diameter difference).

305/30R19 is 0.47 in taller than 285/30R19 and 20 mm wider, a 1.84% difference in overall diameter.

With the speedometer calibrated for 285/30R19, an indicated 60 mph is actually 61.1 mph on 305/30R19, and revolutions per mile change from 784 to 770.

Both sizes mount on 19-inch wheels.

Size pages

Other comparisons with 285/30R19

Other comparisons with 305/30R19

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