1938 De Soto Tire Fitment Guide

1938 De Soto vehicles use two tire sizes: 650-16 for the 1938 De Soto 6 Air Stream and 600-16 for the 1938 De Soto 6 S-5. Both are 16-inch bias-ply fitments, but they are not interchangeable across the full De Soto range for the year. The 650-16 products listed here are built for 4.50- to 5.00-inch rims, while the 600-16 products with published fitment details are built for 4.00- to 4.50-inch rims.

The important takeaway is that a 1938 De Soto owner should identify the model before choosing a tire size, even though both cars use 16-inch wheels. Once the model is confirmed, rim width becomes the next checkpoint, since the two sizes call for different wheel widths. That helps prevent choosing a tire that shares the same wheel diameter but is wrong for the car’s original fitment or wheel dimensions.

On a 1938 De Soto, 650-16 is a numeric bias-ply tire size. The 6.50 figure is the nominal section width expressed in the traditional pre-metric style, and the 16 identifies the wheel diameter in inches. On this year’s De Soto range, that size belongs to the 6 Air Stream and uses a bias-ply construction consistent with late-1930s American passenger cars.

A buyer looking at 650-16 should think in terms of maintaining the correct model-specific fitment for a 1938 De Soto 6 Air Stream rather than converting formats. Since several sidewall treatments are available in this size, the choice usually becomes one of restoration appearance rather than a question of modern versus vintage construction. It is still wise to confirm the wheel width before finalizing the tire.

No, 1938 De Soto models do not all use the same tire size. The 6 Air Stream uses 650-16, while the 6 S-5 uses 600-16. Both sizes mount on 16-inch wheels and both are bias-ply, but the model determines which size belongs on the car.

That distinction matters because some owners know only the year and make when they start searching for tires. With a 1938 De Soto, that is not enough to narrow the fitment correctly. If the model designation on the car is unclear, checking the car’s identification information, wheel width, and existing tire markings can help point you to the right size before you compare brands or sidewall styles.

1938 De Soto tires are available in both blackwall and wide whitewall styles, depending on the size and brand selected. In 650-16, listed offerings include blackwall and wide whitewall versions from several brands, and 600-16 also includes both blackwall and wide whitewall choices. That gives owners of either 1938 De Soto model room to tailor the tire’s appearance to the look they want.

For a restoration-minded 1938 De Soto owner, sidewall style can change the personality of the car almost as much as wheel finish or hubcaps. A blackwall look tends to feel more restrained and workmanlike, while a wide whitewall brings a stronger period presentation. The right choice depends on how the car is being finished, whether it is being judged, and what visual style best matches the era-correct presentation you want.

Several brands make tires for 1938 De Soto vehicles. The 650-16 size is available from BFGoodrich, Coker Classic, Firestone, and Garfield, while the 600-16 size is available from BFGoodrich, Coker Classic, Avon, and Firestone. All of the products listed for these De Soto sizes use bias-ply construction, which matches the period of the car.

Brand choice on a 1938 De Soto often comes down to the look you want and the specific version offered in the correct size. Some owners focus on a familiar American name for a restoration, while others are drawn to a particular tread style or sidewall treatment. It makes sense to narrow the correct size first, then compare the brand options that exist within that exact fitment rather than cross-shopping between the two model-specific sizes.

For a 1938 De Soto, BFGoodrich and Firestone both offer period-style bias-ply tires in the correct numeric sizes, but the available sidewall treatments and published dimensions differ by product. In 650-16, both brands list wide whitewall and blackwall style representation, with 4.50- to 5.00-inch rim fitment and a 1580-pound load rating at 32 psi on the products carrying full specifications. In 600-16, both brands offer period-correct bias-ply construction, and the products with published fitment details use 4.00- to 4.50-inch rims with a 1400-pound load rating at 32 psi.

The practical difference for most 1938 De Soto owners is less about one brand being universally better and more about selecting the exact look and specification set that matches the car. If you are comparing two products in the same size, check the sidewall style first and then compare rim width suitability and load information where published. That keeps the decision focused on your actual model and wheel rather than on brand name alone.

Rim width depends on the tire size used on the specific 1938 De Soto model. The 650-16 fitment used on the 1938 De Soto 6 Air Stream is paired with products built for 4.50- to 5.00-inch rims, while the 600-16 fitment used on the 1938 De Soto 6 S-5 is paired with products built for 4.00- to 4.50-inch rims. Both sizes use a 16-inch wheel diameter, but the wheel width range is different.

That makes wheel measurement especially important on a car that has changed hands, been restored decades ago, or may have had wheels swapped. A 16-inch wheel alone does not guarantee the correct fit for either 1938 De Soto size. Measuring the actual wheel and matching it to the intended tire size is the safest way to avoid an incorrect combination that affects profile, bead seating, or the finished look of the car.

Original 1938 De Soto wheels can use either of the listed tire sizes only if the wheel belongs to the correct model and falls within the proper rim width range for that size. Both 650-16 and 600-16 fit 16-inch wheels, but the 650-16 size is intended for wider rims than the 600-16. Shared wheel diameter does not make the two sizes interchangeable across all 1938 De Soto applications.

For an owner sorting out a parts car, loose wheels, or an old restoration, that means wheel diameter is only the first checkpoint. The next step is confirming whether the wheel width matches the intended tire and whether the car is a 6 Air Stream or a 6 S-5. Treating both sizes as interchangeable just because they are 16-inch tires can lead to an incorrect setup for the model.

A 1938 De Soto should be stored in a cool, dry space away from direct sunlight, electric motors, battery chargers, welders, and other ozone-producing equipment that can accelerate rubber aging. Because these are bias-ply tires, long periods of sitting can encourage flat-spotting more readily than many later radial designs. Keeping the tires clean, properly inflated, and off damp surfaces also helps preserve their condition.

If the car will sit for months at a time, moving it periodically can help change the tire’s footprint and reduce the chance of a persistent flat spot. Some owners also use stands to remove part of the static load during long-term storage, while keeping suspension considerations in mind. A breathable car cover and a stable indoor environment do more for tire life on a 1938 De Soto than occasional cosmetic dressing.

Tires on a 1938 De Soto should be evaluated more by age than by mileage. Collector-car tires often spend long periods parked, so rubber aging, heat cycling, and storage conditions matter more than tread wear alone. A practical rule is to inspect closely once a tire reaches the five- to seven-year range and to treat roughly ten years as the point where replacement deserves serious consideration, regardless of remaining tread.

That approach is especially important on a lightly used prewar car, because an older-looking tire can still appear presentable while the rubber has hardened or begun to crack internally. Checking the date code and maintaining a record of installation age makes long-term planning easier. A 1938 De Soto that sees occasional tours or parade use still benefits from age-conscious replacement rather than waiting for visible failure.

Tires on a 1938 De Soto should be inspected before every drive, and they deserve a more deliberate check before any longer outing. Look for sidewall cracking, cuts, bulges, uneven wear, and signs that the tire has lost pressure while parked. Since these cars are commonly driven infrequently, a tire can deteriorate between outings even when the tread still looks usable.

A longer pre-drive inspection should also include the spare and the valve stems, because an overlooked stem problem can create the same roadside issue as a damaged tire. On an older De Soto, tire condition is only one part of readiness, but it is one of the fastest things to verify before leaving home. Regular inspection helps catch age-related issues before they turn into vibration, wandering, or a roadside failure.

The 1938 De Soto 6 Air Stream uses a 650-16 bias-ply tire, which is fully consistent with the construction type American passenger cars used in the late 1930s. That makes a bias-ply 650-16 the correct starting point for an owner restoring a 6 Air Stream to period form. Sidewall finish can still vary within that size, so restoration goals and the specific presentation of the car remain part of the decision.

Owners pursuing high-level authenticity should confirm market-specific and trim-specific details through De Soto club resources, factory literature, and experienced restorers. The important point is that a 1938 De Soto 6 Air Stream belongs in the 650-16 bias-ply category, not in the smaller 600-16 fitment used on the 6 S-5. Once the size is correct, the visual details of sidewall style become the next authenticity question.

Correct tire fitment absolutely matters when showing a 1938 De Soto. Judges and knowledgeable enthusiasts notice whether the size matches the model, whether the construction type is appropriate to the era, and whether the sidewall style suits the car’s presentation. A 650-16 on a 6 Air Stream and a 600-16 on a 6 S-5 keep the fitment aligned with the proper model-specific setup.

What gets marked down depends on the event, but obvious mismatches in size or a sidewall treatment that looks out of place for the restoration theme can undermine an otherwise careful presentation. Event rules are not always identical, so marque clubs and judging manuals remain the best source for class-specific standards. For most owners, getting the model, size, and overall period look right covers the biggest authenticity concerns.

The 1938 De Soto 6 S-5 uses a 600-16 bias-ply tire, which aligns with what a late-1930s De Soto would have carried in period. Bias-ply construction is the correct foundation for an authentic 6 S-5 presentation, and the listed 600-16 offerings keep that construction style intact. Within that size, the visible choice becomes whether the car is better suited to blackwall or wide whitewall treatment.

That means an owner restoring a 1938 De Soto 6 S-5 should start with size and construction first, then refine the look with the sidewall style that best matches the car’s intended finish. It is worth checking original photos, factory literature, and De Soto enthusiast resources if the goal is a very specific presentation. The key point is that the 6 S-5 does not share the 6 Air Stream’s larger 650-16 fitment.

1938 De Soto tires can be suitable for highway use when they are the correct size, in sound condition, properly inflated, and used within the tire’s stated capabilities. The 600-16 offerings include at least one H-rated product, which corresponds to a 130 mph ceiling, while the other listed products use traditional bias-ply size designations without that modern speed-letter format. In normal real-world use, the car’s brakes, steering, suspension, and general mechanical condition are usually more limiting than the raw speed ceiling of the tire.

The better question for a prewar De Soto is not whether it can theoretically sustain modern highway speeds, but whether the entire car is prepared for the trip. Freshly inspected tires, correct pressures, and stable road manners matter more than chasing speed capability on a vehicle of this age. If a 1938 De Soto feels unsettled, wanders, or vibrates, the answer is to inspect the whole setup rather than assume the issue is only the tire construction.

Inflation pressure on a 1938 De Soto should start with the factory recommendation for the specific model and then be cross-checked against the tire manufacturer’s published limits for the exact product. Several 650-16 products list a maximum load of 1580 pounds at 32 psi, and several 600-16 products list a maximum load of 1400 pounds at 32 psi. Those figures identify rated load pressure for those particular tires, not a universal blanket setting for every driving situation.

The safest approach is to use the original vehicle literature as the baseline for normal operation and to treat the tire’s maximum-rated pressure as a cap tied to load capacity, not a default target. Pressure should never be borrowed from one 1938 De Soto size and applied to the other just because both are 16-inch tires. A careful pressure check when the tires are cold is one of the simplest and most valuable habits for stable road behavior.

Before taking a 1938 De Soto on a longer drive, inspect each tire for cracking, cuts, bulges, uneven wear, and signs of aging around the sidewall and tread. Check cold pressure, confirm the spare is usable, and make sure the valve stems are in good shape. Tire readiness should then be viewed as one part of a broader pre-drive inspection that includes brakes, cooling, steering, and wheel-bearing condition on a car of this vintage.

Longer trips magnify small issues that may never show up on a short local drive. A collector car that has sat comfortably in the garage can still develop low pressure, hardened rubber, or an overlooked spare that is no longer roadworthy. Giving the tires a serious inspection before departure helps the 1938 De Soto feel more settled on the road and reduces the chance that an age-related tire issue interrupts the outing.