1926 DuPont Tire Fitment Guide

1926 DuPont vehicles in this range use two tire sizes: 32X6.20 and 650-20, and both apply to the 1926 DuPont D. The sizes share 20-inch wheel fitment, while the available 650-20 products show a published rim-width range of 3.00 to 5.00 inches on Firestone examples. Both sizes are bias-ply rather than radial, which is consistent with a luxury car from the mid-1920s.

That means a 1926 DuPont owner should start by confirming which of the two vintage size conventions belongs on the car, instead of assuming every 20-inch tire is interchangeable. Once the correct size family is established, the next decision is usually visual and use-oriented, such as blackwall versus whitewall appearance and whether the goal is a highly period-authentic restoration or a more general collector-driver presentation.

On a 1926 DuPont, 32X6.20 is an antique diameter-by-section size. The first number, 32, refers to the tire’s overall diameter in inches, while 6.20 refers to the nominal section width. That differs from later sizing systems because the first number is not the wheel diameter. For the 1926 DuPont D, this size still corresponds to 20-inch wheel fitment in practical application.

That older style of marking matters because it can easily be confused with later numeric sizing if you are reading a sidewall, an old fitment note, or restoration paperwork. A 1926 DuPont owner using 32X6.20 should stay within that antique sizing family rather than translating by appearance alone. If the car is being restored for accuracy, it is wise to compare the existing wheel and any surviving period references before finalizing the tire choice.

On a 1926 DuPont, 650-20 is a numeric bias-ply size. The 6.50 figure represents nominal section width, and the 20 indicates the wheel diameter in inches. It is a later and more familiar vintage format than 32X6.20, but it is still a period bias-ply code rather than a modern metric size. For the 1926 DuPont D, 650-20 is one of the correct fitment families to consider.

That size gives a 1926 DuPont owner the broadest product visibility here, including both blackwall and wide whitewall choices from multiple brands. It is often the easier format for modern buyers to understand because the wheel diameter is stated directly in the size itself. Even so, the right move is to confirm that your particular DuPont D belongs in the 650-20 family before choosing a sidewall style or a specific tire line.

A 1926 DuPont owner should choose between 32X6.20 and 650-20 by confirming which size family belongs on the car, not by treating them as casual substitutes. Both are period bias-ply sizes used on the DuPont D, and both center on 20-inch wheel fitment. The difference is the sizing convention itself: 32X6.20 is an antique diameter-by-section expression, while 650-20 is a numeric bias-ply expression.

Once the correct size family is established, the choice becomes much easier. If your goal is a restoration that follows the earlier antique-style marking system, 32X6.20 is the size to pursue. If your car is set up for the numeric 650-20 convention, that path also opens up visible choices in sidewall appearance. The safest approach is to match the actual wheel and existing fitment history on your DuPont D before narrowing the tire selection.

1926 DuPont tires in the 650-20 size are available with both blackwall and wide whitewall sidewall styles. Firestone offers both blackwall and a 3.75-inch wide whitewall presentation in that size, while Denman and Deka appear in blackwall form. All of those options remain within period-appropriate bias-ply construction, so the visual difference is mainly the sidewall treatment rather than a change in basic era-correct tire type.

That matters because a 1926 DuPont carries a formal luxury-car profile, and sidewall style has a major effect on the finished stance. A blackwall look tends to read more restrained and utilitarian, while a wide whitewall gives the car a more dressed, upscale appearance often favored on Full Classic-era restorations and display cars. The right choice depends on how your specific DuPont D is being presented and what look best suits its restoration theme.

Three brands appear in the currently available 1926 DuPont range: Firestone, Denman, and Deka. Those brand choices are present in 650-20, and all of them are bias-ply offerings. Firestone is represented with both blackwall and wide whitewall options, while Denman and Deka appear in blackwall form. That gives the 1926 DuPont owner a mix of visual styles and brand character within the same basic vintage size.

For a collector, the brand decision usually comes after the fitment decision. Start by confirming whether your DuPont D should be on 32X6.20 or 650-20, then compare the brands that exist within that size. If appearance matters most, Firestone’s sidewall variety may be the deciding factor. If your goal is a straightforward period-style blackwall presentation, the available Denman and Deka options keep the look more understated.

Published rim-width guidance appears for 1926 DuPont tires in the 650-20 size, where Firestone examples list a usable rim-width range of 3.00 to 5.00 inches on a 20-inch wheel. That gives a practical reference point for the DuPont D when 650-20 is the confirmed size family. The products shown in that range are all bias-ply tires, so the measurement should be treated as a vintage-style fitment guideline rather than as a modern low-profile benchmark.

A 1926 DuPont owner should still verify the actual wheel before making a final selection, especially on a car that may have had wheel changes or restoration work over the years. Rim width affects how the tire sits and how authentic the finished profile looks on a large pre-war luxury chassis. Matching the tire to both the wheel diameter and the approved rim-width range is the best way to avoid an awkward stance or bead-fit issues.

The two tire sizes used on the 1926 DuPont D both center on 20-inch wheel fitment, so they share the same basic rim diameter. That means the original 1926 DuPont wheels can often remain within the correct diameter family whether the car is set up for 32X6.20 or 650-20. What does not automatically follow is width compatibility across every wheel and every tire version.

A 1926 DuPont owner should confirm the wheel itself before assuming the same rim works equally well with either size family. Vintage cars may have replacement wheels, mixed components, or prior restoration choices that changed the setup. If you are moving within the 20-inch fitment family, diameter is the easy part; the more important check is whether the actual wheel width aligns with the specific tire being considered and preserves the correct visual proportion.

A 1926 DuPont should be stored in a cool, dry, dark space away from direct sunlight, electric motors, battery chargers, furnaces, and other ozone-producing equipment that can accelerate sidewall cracking. Because the 1926 DuPont uses bias-ply tires, long static storage can also encourage flat-spotting more readily than many later radial applications. Clean floors, stable temperature, and protection from moisture all help preserve both rubber and wheels.

Collectors usually get the best results by moving a 1926 DuPont slightly from time to time or supporting the car in a way that reduces prolonged stress on one contact patch. Tire pressure should be kept at a healthy operating level during storage rather than left partially deflated. If the car sits for an extended season, include the spare in the same routine so every tire on the car remains part of the preservation plan.

Tires on a 1926 DuPont should be judged more by age and condition than by mileage, because collector cars often accumulate very few miles while the rubber continues to age. A good rule is to begin careful age-based evaluation around five to seven years and to treat around ten years as a point for serious replacement consideration, even if tread wear still looks modest. The DOT date code on the tire provides the manufacturing age reference where applicable.

That approach matters on a 1926 DuPont because a seldom-driven car can still develop sidewall cracking, internal aging, or casing fatigue that is easy to overlook in a garage-kept restoration. Owners often focus on tread depth when the more important questions are age, storage history, and visible rubber condition. If the car is used for tours or long event drives, replacing older tires before they become visibly distressed is usually the more prudent path.

Tires on a 1926 DuPont should be inspected before every drive and given a more thorough check before any extended outing. Look for sidewall cracking, cuts, bulges, irregular wear, weathering around the bead area, and any sign that the tire is no longer holding pressure consistently. On a vintage bias-ply application, small condition changes can affect ride and tracking sooner than many owners expect on a low-use collector car.

A 1926 DuPont that is used only occasionally can actually benefit from more disciplined inspections, not fewer, because age-related issues develop quietly during storage. If the car has been parked for weeks or months, check inflation and examine each tire closely before rolling out. Include the spare in that routine so you are not relying on an equally aged, neglected backup if a roadside tire problem interrupts a tour or event drive.

The 1926 DuPont D belongs to an era when bias-ply construction was the original standard, and the size families used here are 32X6.20 and 650-20. Both are period-correct vintage expressions for a car of this age and type, and both center on large 20-inch fitment. Original-equipment branding should not be assumed from modern reproduction availability alone, since luxury marques could vary by market, coachwork, and owner preference even when the construction type stayed consistent.

For a restoration, the most accurate path is to treat bias-ply construction as the baseline and then confirm whether your particular DuPont D belongs in the antique 32X6.20 convention or the numeric 650-20 convention. Surviving manuals, period photographs, and marque-club knowledge can help settle that question when the car’s history is being reconstructed. That extra step is worthwhile because getting the size format right contributes as much to authenticity as choosing the right sidewall look.

Correct tire fitment matters a great deal when showing a 1926 DuPont, especially because pre-war luxury cars are judged as complete visual compositions rather than just mechanical artifacts. Size family, construction type, and sidewall style all affect whether the car presents as convincingly era-correct. A mid-1920s DuPont shown with the wrong size convention or a sidewall treatment that clashes with the car’s restoration style can draw unwanted attention even when the rest of the vehicle is beautifully finished.

For most event and concours settings, the safest standard is to keep the 1926 DuPont within the proper bias-ply look and to match the size family to the car’s known fitment history. Whitewall versus blackwall can also matter depending on the car’s presentation and the judging expectations of a given event. Marque clubs and event rule books are still the best authorities for final judging standards, especially on rare classics with limited surviving reference material.

For the 1926 DuPont in 650-20, Firestone, Denman, and Deka all appear as bias-ply options, but they differ most clearly in sidewall presentation and the amount of published detail available. Firestone is offered in both blackwall and 3.75-inch wide whitewall form and lists a 2120-pound maximum load at 60 psi with a 3.00 to 5.00 inch rim-width range on the examples shown. Denman and Deka appear in blackwall form, with a more utilitarian visual character in the available range.

That makes Firestone especially relevant when a 1926 DuPont owner wants a choice between a dressier luxury appearance and a more restrained look without leaving the same basic size. Denman and Deka may appeal to owners who prefer a straightforward blackwall presentation on a large classic chassis. The right answer depends less on abstract brand hierarchy and more on how your DuPont D is being restored, displayed, or driven within its established 650-20 fitment family.

1926 DuPont tires can be suitable for highway use when they are the correct size, in sound condition, and used within the limits of their bias-ply construction. The available range shown here does not list modern passenger-car speed ratings for these vintage sizes, so the practical safety question is usually less about chasing high-speed capability and more about condition, inflation, and the overall readiness of a pre-war automobile. On a 1926 luxury car, chassis age and braking behavior often become the more meaningful constraints at normal road speeds.

A 1926 DuPont owner planning sustained highway travel should approach the car as a complete system rather than thinking about the tires in isolation. Freshly inspected tires, stable pressures, sound wheels, and a mechanically sorted suspension and brake system matter more than aggressive speed expectations. Vintage bias-ply tires reward measured driving and regular checks, and they are best matched to the steady touring style that suits a large Classic Era automobile in the first place.

Inflation pressure for 1926 DuPont tires should follow the size and the tire maker’s published rating rather than a one-number-fits-all rule. In the available 650-20 range, Firestone examples list a maximum load capacity of 2120 pounds at 60 psi. That figure is a rated maximum for that tire specification, not an instruction to apply the same pressure to every brand, every size, or every wheel setup on a 1926 DuPont.

The best practice is to start with the original vehicle literature if it is available, then confirm the tire maker’s guidance for the exact product you are running. A 1926 DuPont owner should avoid transferring a pressure figure from 650-20 to 32X6.20 or from one brand to another without verification. Proper pressure on a pre-war bias-ply application affects ride height, steering feel, tire wear, and casing stress more than many modern drivers expect.

Before a longer drive, a 1926 DuPont should have each tire inspected for cracking, cuts, bulges, unusual wear, and secure valve condition, along with a pressure check when the tires are cold. The spare deserves the same attention, because a neglected backup tire is little help on a touring route. Since the DuPont D uses large vintage bias-ply fitment, a visual walk-around can reveal stance changes or underinflation before those problems become much more noticeable on the road.

That tire inspection should be part of a broader pre-drive check suited to a 1926 automobile: wheels, brakes, steering, fluids, and any age-sensitive chassis hardware all deserve attention before distance driving. A long outing puts sustained heat and load into every component, not just the tires. Taking ten extra minutes in the garage is often what separates a relaxed classic-car tour from an avoidable roadside interruption in a rare and valuable pre-war car.