What size wheels are on a 1931 Model A?
21-inch wheels with 4.50-21 tires on the front and rear.
The 1931 Model A, Ford’s final year of the Model A era, used 21-inch wheels as the standard diameter, with tires typically sized 4.50-21 on both axles. Variants and replacements could alter the specific tire width, but the 21-inch wheel remains the defining feature of stock Model A setups. This article reviews the standard sizing and common variations you may encounter when restoring or maintaining a 1931 Model A.
Standard wheel and tire sizing
Baseline configuration and what that means for restoration and maintenance.
- Wheel diameter: 21 inches (the stock metric for the Model A).
- Typical tire size: 4.50-21 used on both front and rear axles.
- Uniform axle sizing: Front and rear wheels were generally the same size in stock form.
Notes: While 21-inch wheels with 4.50-21 tires are the standard, some cars or restorations may use near-equivalents if original tires are unavailable. Always verify with the car’s data plate or owner's manual for exact specifications.
Variations you may encounter
These variations commonly show up in real cars due to production year, maintenance history, or aftermarket parts.
Stock configurations vs. restorations
The wheel diameter tends to stay at 21 inches, but restorers may encounter slightly different tire widths or near-equivalent tire codes when exact 4.50-21 tires aren’t available.
- Year-to-year and replacement variations: The 21-inch wheel diameter was standard, though the related tire width could vary slightly by availability and replacement parts.
- Front vs. rear consistency: Stocks typically used matching wheel sizes on both ends; variations are more common in non-original setups.
- Aftermarket options: Modern reproductions and aftermarket tires may use close but not identical widths while preserving the 21-inch diameter.
In practice, the defining feature remains a 21-inch wheel with a closely matched 4.50-21 tire standard for most Model A cars.
Summary
The standard wheel size for a 1931 Model A is a 21-inch diameter wheel, commonly paired with 4.50-21 tires on both front and rear. While this pairing is the baseline, you may encounter minor variations due to year-specific production details or restoration choices. For precise restoration, confirm the exact specs with the vehicle’s data plate or original documentation.
