1927 DuPont Tire Fitment Guide

1927 DuPont vehicles in this range use two tire sizes: 32X6.20 and 650-20, and both apply to the DuPont E. Both sizes are bias-ply fitments and both mount on 20-inch wheels. For the 650-20 size, applicable products include a listed rim-width range of 3.00 to 5.00 inches on the products where rim-width information appears.

That means the key question is not which 1927 DuPont model you have, but which tire size convention your wheels and restoration plan call for. If your car is already fitted with a known size, use that as your starting point. If you are rebuilding from bare wheels or mixed parts, confirm the wheel dimensions and compare the car against marque references before settling on either 32X6.20 or 650-20.

On a 1927 DuPont, 32X6.20 is an antique diameter-by-section size. The first number, 32, refers to the tire’s approximate overall diameter in inches, while 6.20 refers to the nominal section width. It is a bias-ply format from the period when tire sizing was often expressed by outside diameter and section width rather than by the later numeric width-and-rim convention.

That size notation matters because it points to an earlier style of fitment language, even though the tire still mounts on a 20-inch wheel. Owners pursuing an authentic late-1920s presentation often pay close attention to this distinction. If your DuPont E has existing tires, wheel tags, or restoration paperwork using 32X6.20, it is smart to stay within that same format unless a knowledgeable DuPont specialist confirms a different interchangeable size for your specific car.

On a 1927 DuPont, 650-20 is a numeric bias-ply size. The 6.50 portion identifies the nominal section width in inches, and the 20 identifies the wheel diameter in inches. It is a later vintage sizing convention than 32X6.20, but it still belongs squarely in the period-correct bias-ply world for an automobile of this era.

The practical advantage of 650-20 is that it has current product coverage in several brand and sidewall combinations, including blackwall and wide whitewall options. That gives DuPont E owners more room to match appearance and intended use without leaving the proper construction type. Before choosing one, compare the tire size already on the car, verify the wheel width, and decide whether your goal is a strict antique-style notation or a numeric bias-ply replacement path.

Both sizes are bias-ply options for the 1927 DuPont E and both mount on 20-inch wheels, so the choice usually comes down to which period size convention matches your car. 32X6.20 reflects an antique diameter-by-section notation, while 650-20 uses the more familiar numeric bias-ply format. The currently listed product range is concentrated in 650-20, which gives that size more visible variety in available sidewall treatments and brands.

If your DuPont is being restored with close attention to how the tire size itself is presented, match the notation already associated with the car whenever possible. If you are working from existing 650-20 tires or want the broadest range of presently listed options, 650-20 is the easier path to compare. The safest approach is to check the size on the wheel and the car first, then choose the size convention that aligns with your restoration standard.

For 1927 DuPont tires in the currently represented 650-20 size, sidewall styles include blackwall and wide whitewall. Firestone appears in both blackwall and a 3.75-inch whitewall version, while Denman and Deka are represented in blackwall form. All of those listed products remain bias-ply, which keeps them within the expected construction family for a 1927 luxury car.

Sidewall choice changes the car’s visual character more than its fitment. Blackwalls tend to suit a more restrained or utilitarian period look, while a wide whitewall can give a DuPont E a more formal, upscale presentation that many collectors favor on premium late-1920s automobiles. If your car is being judged, verify what your event or marque authority considers appropriate for the body style, market, and restoration period you are aiming to represent.

Three brands appear in the currently listed 1927 DuPont tire offerings for the 650-20 size: Firestone, Denman, and Deka. Firestone is shown in both blackwall and wide whitewall classic bias-ply form, while Denman and Deka are represented with blackwall bias-ply products in classic truck-oriented series. All of them share the same basic 650-20 size and 20-inch wheel diameter.

Brand choice on a car like a 1927 DuPont often comes down to the look you want and the specific product character available in that size. A Firestone wide whitewall creates a different visual result than a blackwall Denman or Deka, even though the basic size remains the same. Once you have confirmed your preferred size, compare sidewall appearance, any listed rim-width range, and load information where available before making your final decision.

For 1927 DuPont tires, the 650-20 products shown with rim-width information call for wheels in the 3.00- to 5.00-inch range. Both 32X6.20 and 650-20 use a 20-inch wheel diameter, but rim-width guidance is specifically listed on applicable 650-20 products. That makes wheel width an important confirmation point before choosing among the currently available 650-20 offerings.

Owners should measure the actual wheel rather than relying on assumptions from age or appearance alone. A 20-inch wheel can still vary in width, and vintage cars are often found with replacement or swapped wheels from earlier repairs. If your 1927 DuPont is already assembled, check the wheel stampings where possible and compare them with the tire manufacturer’s approved range for the exact product you are considering.

Original 1927 DuPont wheels can generally be considered compatible at the rim-diameter level with both listed tire sizes, because both 32X6.20 and 650-20 are 20-inch fitments for the DuPont E. That shared wheel diameter is the main common point between the two sizes. The remaining question is whether the wheel width and the car’s existing fitment history align with the exact tire you plan to use.

That is why original wheels should be checked carefully before a tire decision is finalized. Restored wheels can be altered, and surviving cars sometimes carry wheels from another period or repair. If your goal is to move between 32X6.20 and 650-20, confirm the actual wheel dimensions and compare them against the recommended rim-width range for the specific tire you want rather than assuming every 20-inch wheel is interchangeable.

A 1927 DuPont should be stored in a cool, dry, dark environment with the tires kept away from direct sunlight, electric motors, battery chargers, welders, and other ozone-producing equipment. Bias-ply tires are more prone to flat-spotting during long static storage than later radial designs, so tire care matters even when the car is driven only occasionally. Clean floors and stable temperature also help reduce moisture-related deterioration.

For a collector car that sits for extended periods, maintain proper inflation and roll the car periodically so one part of the tread is not carrying the load for months at a time. Some owners use stands to reduce sustained load, but they should support the car correctly and avoid stressing the chassis. When the DuPont comes back into use, inspect the sidewalls and let the tires warm up gently before any longer drive.

Tires on a 1927 DuPont should be evaluated more by age than by mileage. On collector vehicles, a five- to seven-year review window is a sensible point for closer inspection, and around ten years is a common threshold for serious replacement consideration even if tread depth still looks acceptable. The date code on the tire remains one of the best guides to its actual age.

That guideline matters because an older luxury car may cover very few miles while the rubber still hardens, cracks, or loses resilience over time. A tire that looks visually decent in the garage can still be past its ideal service life. If your DuPont is driven only for shows or occasional tours, make age checks part of routine maintenance rather than assuming low annual mileage automatically means the tires are still ready for use.

Tires on a 1927 DuPont should be inspected before every drive and again before any extended outing. Look for sidewall cracking, cuts, bulges, embedded objects, uneven wear, and any sign that a tire has lost pressure since the last time the car was moved. Vintage bias-ply tires deserve especially close visual checks because collector cars often spend long periods parked between uses.

A quick inspection is usually enough to catch age-related issues before they become a roadside problem. Include the spare in the same routine, since it may be decades old even if it has never touched the road. If your setup uses tube-type components or older valve hardware, inspect the valve stems and inflation behavior as part of the same pre-drive check rather than treating the tread surface as the only concern.

A 1927 DuPont E would originally have been a bias-ply automobile, because bias-ply construction was standard for American passenger cars of the period. Within the fitments associated with this year and make, the DuPont E is tied to 32X6.20 and 650-20 sizing, both on 20-inch wheels. That places the car firmly in the correct prewar bias-ply tire world rather than in any modern radial category.

For strict originality work, the remaining question is which of those period size conventions is correct for your specific car, body style, and restoration standard. Surviving luxury cars from the 1920s can have mixed histories, including replacement wheels and later service substitutions. A DuPont club resource, period sales literature, or judged-event handbook is the right final check if you are aiming for highly exact presentation rather than simply era-appropriate fitment.

Correct tire fitment matters a great deal when showing a 1927 DuPont, especially in concours or authenticity-focused judging. Judges and knowledgeable enthusiasts often notice whether the size convention, construction type, and sidewall appearance suit the period. On a late-1920s luxury car, a visibly modern construction or an obviously out-of-era sidewall presentation can stand out even if the tire physically fits the wheel.

That does not mean every event applies the same standard, so the smartest move is to match the level of correctness to the kind of judging you expect. A broadly period-appropriate bias-ply setup may be fully satisfactory for touring and casual shows, while top-tier judged events may reward closer attention to the exact size notation and whitewall treatment. Review your event rules early so your tire decision supports the restoration goal instead of conflicting with it.

For the 1927 DuPont in 650-20, Firestone appears in both blackwall and 3.75-inch whitewall classic bias-ply form, while Denman and Deka appear as blackwall bias-ply products in truck-oriented series. The Firestone listings include a 20-inch rim diameter, a 3.00- to 5.00-inch rim-width range, and a maximum load rating of 2120 pounds at 60 psi on the products where load information is shown. Listed weights also vary, with Firestone examples shown at 28 and 33 pounds and Denman and Deka at 32 pounds.

Those differences matter mainly in appearance and in the level of specification detail available for comparison. A Firestone whitewall creates a more formal visual effect on a luxury car, while blackwall versions from any of the listed brands keep the look more restrained. If you are narrowing the field, compare whitewall versus blackwall first, then check rim-width compatibility and any listed load information for the exact product you intend to run.

1927 DuPont tires in the listed sizes are bias-ply designs, and no speed ratings are shown in the available product information here. That means highway use should be approached as a system question rather than a simple tire-speed question. On a late-1920s luxury car, the age of the tire, the condition of the wheel, and the car’s braking, steering, and suspension condition are usually just as important as the nominal tire size itself.

A properly maintained DuPont on fresh, correctly fitted bias-ply tires can be driven on public roads, but sensible speeds and careful trip planning remain part of vintage-car ownership. Before any sustained road use, inspect the tires closely and make sure the car tracks properly and holds pressure. Short shakedown drives are wise after installation, especially if the car has been off the road or if the wheels and tires are a new combination.

Inflation pressure on a 1927 DuPont should be matched to the exact tire you are using and the guidance for that specific size and construction. For the listed 650-20 Firestone products, the tire shows a maximum load capacity of 2120 pounds at 60 psi, which is a tire rating rather than a blanket instruction to run every 1927 DuPont tire at that pressure. Pressure should never be transferred casually from one size to another.

The best practice is to start with the vehicle’s period factory recommendation when available, then compare it with the tire maker’s load and pressure guidance for the exact reproduction tire you have chosen. Collector cars often perform best when pressure is set for the car’s actual weight distribution and intended use rather than by guesswork. After setting pressures, recheck them regularly because long storage periods can cause gradual loss that affects ride and handling.

Before taking a 1927 DuPont on a longer drive, inspect every tire for cracking, cuts, bulges, irregular wear, and proper inflation, and make sure the spare is usable rather than simply present. Confirm that the wheel hardware is secure and that the tires have not developed severe flat spots during storage. On a prewar car, tire condition is only one part of the readiness check, but it is one of the easiest to evaluate before departure.

A longer outing is also a good time to verify that the car steers evenly, brakes straight, and does not show any vibration that might point to tire, tube, or wheel trouble. Bring the basic tools and inflation equipment appropriate to the car’s era, especially if you tour in rural areas. A careful pre-drive inspection takes only a few minutes and is often what separates an enjoyable vintage run from a preventable roadside delay.