DuPont D Tires

The DuPont D has two listed tire sizes for 1926: 32X6.20 and 650-20. The 650-20 products use a 20-inch rim, while 32X6.20 is an antique diameter-by-section size where the wheel diameter is not stated in the size code itself. All currently listed products are bias-ply designs, and the available commercial products are concentrated in 650-20.

That means a DuPont D owner should not choose by year alone. Start by checking the actual wheel on the car, then compare the mounted tire size, the wheel diameter, and any surviving factory or restoration records so the tire matches both the rim and the intended style of restoration.

On a DuPont D, 32X6.20 is an antique tire size format rather than a modern wheel-and-section code. The 32 refers to the tire's approximate overall outside diameter in inches, and 6.20 refers to the section width. The wheel diameter is separate, so it cannot be read directly from the 32X6.20 marking.

That is why this size often causes confusion for modern buyers. If your DuPont D carries a tire marked 32X6.20, confirm the wheel diameter on the car itself and compare the wheel, brake clearance, and body clearance before choosing a replacement, especially if the car has been restored or changed over time.

A 1926 DuPont D can show two tire sizes because the model year sits in a period when older diameter-marked sizing and newer numeric sizing overlapped. One listing is 32X6.20, which uses antique diameter-by-section notation, and the other is 650-20, which uses a numeric bias-ply format tied to a 20-inch wheel. The two markings do not communicate fitment in the same way.

The practical takeaway is that the tire sidewall alone may not tell the whole story unless you understand the format. Check the wheel diameter first, then compare the car’s present setup with restoration paperwork or marque references so you can determine whether your DuPont D belongs with the antique-style size or the 20-inch numeric size.

The listed DuPont D tire options are bias-ply products, and the size formats used here are the traditional tube-type styles associated with vintage applications. That applies both to the antique 32X6.20 format and to the numeric 650-20 bias-ply products. For this DuPont D fitment range, a tube is required.

Tube fitment should be treated as part of the complete tire package rather than an afterthought. When replacing tires on a DuPont D, inspect the wheel condition, valve hole, and rim band or flap requirements at the same time so the tube, tire, and wheel all work together as a proper assembled unit.

The right way to confirm a 1926 DuPont D tire size is to compare three things: the size marking on the existing tire, the actual wheel diameter, and any reliable restoration or factory-era reference attached to the car. That matters because 1926 DuPont D listings include both 32X6.20 and 650-20, and those formats express size differently. The available 650-20 products are built for a 20-inch rim.

A careful inspection in the garage usually settles the question faster than relying on the model year alone. Measure the wheel, read every sidewall marking, and look for signs that the car may have been changed during an older restoration, especially if the current tires and wheels do not appear to be from the same period.

The available DuPont D products in 650-20 include blackwall and wide whitewall sidewall styles. Blackwall appears across several passenger and truck-oriented offerings, while the wide whitewall option appears in a Firestone Classic Bias Ply version. Those choices give buyers a clear difference in visual presentation even within the same nominal size.

Sidewall style should match the character of the restoration as closely as the size does. A DuPont D restored as a formal, upscale road car may call for a different appearance than one being assembled for general touring, so compare surviving photos, judging standards, and the overall finish of the car before settling on blackwall or whitewall.

The current DuPont D product mix includes Firestone, Denman, and Deka in the listed 650-20 size. Firestone appears in both passenger-style and truck-style offerings, while Denman and Deka appear in truck-oriented bias-ply lines. All are vintage-style products intended for older wheel and fitment conventions.

Brand choice should come after fitment is settled, not before. Once the wheel diameter, intended appearance, and use case are confirmed on your DuPont D, compare each brand’s sidewall style, tread character, and overall presentation so the tire suits both the car and the way you plan to use it.

The DuPont D products shown in 650-20 span several series: Firestone Classic Bias Ply, Highway Classic Truck, Deka Classic Truck, and Firestone Classic Truck. Firestone Classic Bias Ply is the passenger-car oriented line in this group, while the truck-labeled series are heavier-duty vintage-style offerings built around utility and commercial tread character. All of them are bias-ply constructions.

That distinction matters because a DuPont D restoration may need a very different visual and driving character than a truck-style tire delivers. If the goal is a more authentic passenger-car presentation, start with the passenger-oriented bias-ply choices first, then compare the truck series only if the wheel, use case, or desired look points in that direction.

A DuPont D should be stored in a cool, dry, dark space away from direct sunlight, ozone sources, and large swings in temperature. Keep the tires clean, maintain proper inflation, and avoid letting the full vehicle weight sit in one position for long periods if the car will not be driven regularly. Vintage bias-ply tires benefit from a stable storage environment more than modern daily-driver tires do.

For a collector car like the DuPont D, thoughtful storage extends both appearance and service life. Move the car periodically or support it appropriately during long-term storage, and inspect the sidewalls and tread faces whenever the car comes out for events, touring, or seasonal recommissioning.

Tires on a DuPont D should be inspected before every drive and more thoroughly at regular intervals even if the car sees very little mileage. Check inflation, sidewall cracking, tread separation, bead condition, valve stems, and any signs that the tube or wheel may be contributing to air loss or uneven shape. Bias-ply collector tires can age visibly and structurally long before the tread is worn out.

Low annual mileage often gives owners a false sense of security. A DuPont D that spends most of its life in storage still needs routine inspection because age, storage conditions, and long idle periods can be harder on old-style tires than steady use at modest speeds.

A DuPont D tire should be replaced whenever age, cracking, hardening, flat spotting that does not recover, tread separation, or sidewall distortion appears, even if the tread depth still looks generous. Collector tires often age out before they wear out. Any tire that shows structural deterioration should be treated as finished service-wise regardless of how little the car has been driven.

That standard is especially important on an infrequently used vintage car because storage age can be more significant than mileage. If a DuPont D has older tires of uncertain age, build replacement into the recommissioning process rather than waiting for visible tread wear, and have the wheels and tubes inspected at the same time.

The DuPont D fitment range here includes both 32X6.20 and 650-20 for 1926, which shows that more than one period-appropriate size convention can enter the discussion for this model. The available current products are concentrated in 650-20 and include both passenger-style and truck-style bias-ply series. That gives a useful starting point, but original-equipment choice still needs to be matched to the specific car.

For an authenticity-focused restoration, the best practice is to compare the car against surviving paperwork, period photos, and marque-club guidance before selecting a tire. The DuPont D was a premium automobile, so details like sidewall treatment, tread style, and overall tire stance can make a noticeable difference in how correct the finished restoration feels.

Correct tire fitment can have a meaningful effect on both the visual credibility and judged presentation of a DuPont D. Size, sidewall style, overall profile, and construction type all shape how accurately the car sits and how well it reflects its era. On a rare, high-end 1920s automobile, those details tend to stand out more than they do on a casual driver.

Judging standards can vary, but a DuPont D usually benefits when the tires look appropriate for the period and for the specific restoration goal. If the car is being prepared for concours, club judging, or serious collection display, compare your planned tire choice against period imagery and accepted marque references before final assembly.

The available DuPont D options in 650-20 include both blackwall and wide whitewall styles. Either can create a period-looking presentation depending on how the particular car is being restored, but they project very different visual character. The blackwall choices also extend into truck-style offerings, while the wide whitewall appears in a passenger-oriented Firestone line.

Choosing the correct sidewall for a DuPont D restoration comes down to the specific personality you are trying to recreate. Period photos, surviving original cars, and event judging standards are the best guides, especially on a luxury marque where the difference between blackwall understatement and whitewall formality changes the whole stance of the car.

A properly fitted, correctly inflated vintage-style tire can be suitable for limited public-road use on a DuPont D when the entire car is mechanically sound and the tire matches the wheel and application. The listed DuPont D products are all bias-ply designs, and bias-ply tires behave differently from modern radials in steering feel, tracking, and braking response. Safety depends on the complete vehicle, not the tire alone.

Road use should be approached conservatively on a DuPont D. Before any meaningful driving, make sure the tires, tubes, wheels, brakes, steering, and suspension have all been inspected together, then drive in a way that respects the car’s age, construction, and original operating envelope.

Before driving a DuPont D, check tire inflation, sidewall condition, tread condition, wheel security, valve stems, and any visible tube-related issues such as irregular shape or air loss. Because the 1926 DuPont D can involve either antique-format or numeric sizing, confirm that the mounted tire actually matches the wheel diameter and the intended fitment. A quick visual walk-around is essential every time the car moves.

That inspection should be part of a broader pre-drive routine that includes brakes, steering, lights, and fluid levels. On a collectible car like the DuPont D, problems often show up first in small signs, so catching a low tire, a cracked sidewall, or a loose wheel early can prevent a much larger mechanical or safety issue.

A DuPont D on vintage-style bias-ply tires should be driven at moderate, conservative speeds that suit both the tire construction and the capabilities of a 1920s automobile. Even with new reproduction tires, the handling, braking, and road manners of a DuPont D are from a very different era than modern traffic expectations. The appropriate pace is one that leaves a generous safety margin at all times.

In practice, that means treating the DuPont D as a touring or event car rather than a high-speed machine. Smooth inputs, extra following distance, and reduced speed on rough pavement, crowned roads, or wet surfaces will do more for safe enjoyment than trying to make the car behave like a later automobile.