Model a Ford Tires
Selecting the correct tires for a classic Ford Model A (produced from 1928 through 1931) is one of the most critical decisions in vintage automotive restoration, directly influencing factory period-correct authenticity, handling dynamics, steering effort, and touring road safety. Henry Ford's iconic successor to the Model T rolled out of the factory on welded steel wire spoke wheels. Model A restorations utilize two primary wheel rim diameters: 21-inch rims on early 1928-1929 models, and 19-inch rims on late 1930-1931 vehicles. Restorers must weigh traditional authentic bias-ply tires against modern radial tire alternatives.
Historical Production Sizing: 21-Inch (1928-29) Versus 19-Inch (1930-31)
When the Ford Model A debuted in December 1927 for the 1928 model year, it was equipped with 21-inch welded wire spoke wheels wrapped in 4.40/4.50-21 bias-ply balloon tires. These tall, narrow tires provided generous ground clearance over rutted unpaved dirt and gravel roads common in late 1920s rural America, while their narrow cross-section kept low-speed steering effort manageable on the Model A's non-assisted worm-and-sector steering gear.
For the 1930 and 1931 model years, Ford engineers refreshed the styling, lowering the vehicle's center of gravity and modernizing its stance by transitioning to 19-inch wire wheels fitted with wider 4.75/5.00-19 tires. The 19-inch tires provided improved lateral stability on freshly paved state highways, slightly wider tread contact patches for mechanical drum braking, and a sleeker appearance that defined the late Model A era.
The table below compares factory original wheel and tire specifications across the four production years of the Ford Model A.
| Model Year Range | Rim Diameter & Type | Authentic Factory Tire Size | Recommended Cold Tire Pressure |
|---|---|---|---|
| 1928 to 1929 Model A | 21-Inch Welded Wire Spoke | 4.40 / 4.50-21 Bias-Ply | 35 PSI (Cold inflation pressure) |
| 1930 to 1931 Model A | 19-Inch Welded Wire Spoke | 4.75 / 5.00-19 Bias-Ply | 35 PSI (Cold inflation pressure) |
| Early 1928 (AR Models) | 21-Inch Multi-Spoke Wire | 4.40-21 Firestone / Goodyear | 35 PSI (Cold inflation pressure) |
| Modern Radial Alternative | Fits original 19-inch & 21-inch rims | Custom radial classic casing | 32 to 35 PSI (Check manufacturer spec) |
Maintaining proper 35 PSI inflation pressure is vital; underinflated vintage bias-ply tires wander severely in highway pavement ruts.
Authentic Bias-Ply Tires Versus Modern Steel-Belted Radials
Antique Automobile Club of America (AACA) and Model A Restorers Club (MARC) national concours judging strictly mandates authentic bias-ply tires featuring correct period tread patterns—such as Firestone Gum-Dipped, Goodyear Diamond Tread, or BFGoodrich Silvertown casings. Bias-ply tires feature diagonal criss-cross fabric plies that produce authentic tall sidewall profiles and classic road manners, though they tend to follow highway pavement ruts ('tramlining').
Conversely, for enthusiasts who actively tour cross-country and participate in long-distance driving events, modern specialty radial tires built specifically for vintage wire rims (such as Coker Classic or Excelsior Stahl Sport radials) deliver massive safety upgrades. Modern radials eliminate wandering, enhance directional tracking, significantly reduce emergency braking distances, and provide superior wet-weather grip.
The table below highlights the performance and judging trade-offs between authentic bias-ply and modern radial tires for Model A touring.
| Performance Characteristic | Authentic Vintage Bias-Ply Tires | Modern Classic Radial Tires | Touring Practicality Takeaway |
|---|---|---|---|
| Concours Restoration Judging | 100% Authentic; zero point deductions | Point deductions at strict MARC/MAFCA meets | Bias-ply is mandatory for blue-ribbon show vehicles. |
| Highway Tracking & Tramlining | Prone to wandering in longitudinal ruts | Tracks straight and true; zero rut wandering | Radials significantly reduce driver fatigue on long tours. |
| Wet Weather Braking Grip | Moderate traction on wet asphalt | Superior modern rubber compound and siping | Radials dramatically improve mechanical drum brake safety. |
| Tread Longevity Expectancy | 12,000 to 18,000 Miles | 30,000 to 45,000 Miles | Radials last more than twice as long as bias-ply casings. |
| Inner Tube Requirement | Mandatory heavy-duty inner tube & flap | Mandatory tube (wire wheels are not airtight) | Both tire styles require heavy-duty vintage inner tubes. |
Because Ford Model A wire spoke rims are not airtight, all tires—whether bias-ply or radial—must be installed with heavy-duty butyl rubber inner tubes.
How to Inspect and Mount a Model A Tire and Tube in 4 Steps
Follow this antique automotive procedure to inspect wire rims, install rim flaps, and mount Model A tires safely.
Step 1: Inspect Wire Spoke Welds and Smooth Rim Interior
Examine the wire wheel rim for loose spokes or cracked welds, grinding down any sharp spoke nipple burrs on the inside drop-center well.
Step 2: Install a Heavy-Duty Rubber Rim Flap Band
Stretch a heavy-duty rubber rim flap over the center well of the wheel to prevent the inner tube from chafing against spoke heads or rough metal.
Step 3: Lightly Powder the Inner Tube and Insert into Tire
Dust the inside of the tire casing and the butyl inner tube with talcum powder, partially inflating the tube with 5 PSI to give it shape before insertion.
Step 4: Mount Tire Beads onto Rim and Inflate to 35 PSI
Carefully pry the tire beads over the rim edge using smooth vintage tire spoons, ensuring the tube is not pinched, and inflate to 35 PSI to seat beads.
Frequently Asked Questions (8 Questions Answered)
Q1: What size tires did the Ford Model A come with originally?
Early 1928-1929 Model A cars used 21-inch wire wheels with 4.40/4.50-21 tires; late 1930-1931 models featured 19-inch wheels with 4.75/5.00-19 tires.
Q2: What is the correct tire pressure for a Ford Model A?
The factory recommended cold tire inflation pressure for both 19-inch and 21-inch Model A tires is 35 pounds per square inch (PSI).
Q3: Do Ford Model A tires need inner tubes?
Yes. Model A wire spoke rims are porous and not airtight; all tires require heavy-duty inner tubes and protective rubber rim flaps.
Q4: Can you put radial tires on a Ford Model A?
Yes. Specialty manufacturers produce vintage-sized radials (like Excelsior and Coker Classic) that fit original 19-inch and 21-inch wire wheels for superior handling.
Q5: Were whitewall tires original on the Ford Model A?
Whitewall tires were virtually never installed on standard Model A production cars from the factory; all-black tires are strictly correct for judging authenticity.
Q6: What is a rim flap and why is it necessary on Model A wheels?
A rim flap is a thick rubber band that wraps around the center of the wire rim, shielding the delicate inflatable inner tube from sharp spoke nipple heads.
Q7: How long do vintage Model A bias-ply tires last?
Due to rubber age hardening and ozone cracking, antique tires should generally be replaced every 7 to 10 years regardless of remaining tread depth.
Q8: Why does my Model A pull or wander at highway speeds?
Wandering is often caused by underinflated bias-ply tires (below 35 PSI), loose front kingpins, worn tie-rod ends, or out-of-spec toe-in alignment.
Final Thoughts & Key Takeaways
In conclusion, understanding model a ford tires provides essential clarity, practical strategies, and actionable advice. By incorporating these foundational insights, adhering to verified safety guidelines, and following structured best practices, you ensure reliable, long-term outcomes while preventing common mistakes. Stay informed, consult certified professionals when needed, and maintain consistent quality care.