305/50R20 Tire Size Specifications & Compatible Vehicles

Overall Diameter

813.0 mm

Section Width

305 mm

Sidewall Height

152.5 mm

Circumference

2554.1 mm

Revs/Mile

630

Rim Diameter

20"

Alternative Tire Sizes

These tire sizes are within 3% overall diameter of 305/50R20 and may be used as replacements:

315/40R22 Safe 0.3% · +10mm · +2" rim 285/45R22 Safe 0.3% · -20mm · +2" rim 315/45R21 Safe 0.5% · +10mm · +1" rim 305/45R21 Safe 0.6% · same width · +1" rim 325/40R22 Safe 0.7% · +20mm · +2" rim 285/55R20 Safe 1.1% · -20mm · same rim 295/50R20 Safe 1.2% · -10mm · same rim 305/40R22 Safe 1.3% · same width · +2" rim 295/45R22 Safe 1.4% · -10mm · +2" rim 295/45R21 Caution 1.7% · -10mm · +1" rim 285/65R18 Caution 1.8% · -20mm · -2" rim 285/55R19 Caution 2.1% · -20mm · -1" rim

Understanding 305/50R20

The tire size 305/50R20 means the tire has a section width of 305mm, an aspect ratio of 50% (the sidewall height is 50% of the width), and fits a 20-inch rim.

Sidewall Height = 305 x 0.5 = 152.5 mm
Overall Diameter = (152.5 x 2) + (20 x 25.4) = 813.0 mm
Circumference = 813.0 x π = 2554.1 mm

With an aspect ratio of 50%, this is a standard-profile tire that balances ride comfort with handling precision. This profile range is the most common for passenger cars, crossovers, and light SUVs.

Choosing Replacement Tires

When replacing 305/50R20 tires, verify the size matches your vehicle's tire placard (typically found on the driver's door jamb or in the owner's manual). The NHTSA Tire Ratings Search tool lets you look up manufacturer load and speed ratings for specific tires.

Key factors beyond size: load index (must meet or exceed the vehicle's requirement), speed rating (must match or exceed the original specification), and seasonal type (all-season, summer, or winter) based on your driving conditions. The U.S. Tire Manufacturers Association recommends replacing all four tires at once, or at minimum in pairs on the same axle.