1940 Nash Tire Fitment Guide

1940 Nash vehicles covered here use two sizes: 6.25-16 and 700-16, both on the Nash Ambassador. Both are bias-ply sizes and both mount on 16-inch rims. Rim width guidance appears in available product details for 700-16 at 4.50 to 5.50 inches, which gives a useful reference point when checking an existing wheel before selecting a tire.

The key point is that 1940 Nash fitment is not a make-wide question involving several models with different tire packages. It is an Ambassador question involving two period-style sizes, so the first step is confirming what is already on the car or what the restoration calls for. Once the size is settled, you can narrow the decision by sidewall appearance and brand preference.

On a 1940 Nash, 6.25-16 is a numeric bias-ply size. The first number, 6.25, is the nominal section width in inches, and the second number, 16, is the wheel diameter in inches. Because it is a bias-ply format from the period, it reads differently than later alphanumeric or metric tire sizes familiar to modern drivers.

That matters because a modern-looking size code can lead buyers to compare the wrong type of tire. A 6.25-16 belongs in the vocabulary of prewar American fitment, where sizing was expressed in inches and construction was bias-ply. If your 1940 Nash is being restored with a strong emphasis on period appearance, understanding that code helps keep the car aligned with the era.

Within the 1940 Nash coverage here, the Ambassador is the listed model and it uses two possible tire sizes: 6.25-16 and 700-16. That means the year and make alone do not reduce to one single size, even though the fitment does not branch across a larger model range. Both sizes share the same 16-inch rim diameter and both are bias-ply.

For a buyer, that means the important identification step is not choosing between several Nash model lines, but confirming which size belongs on a particular Ambassador. Existing wheel fitment, restoration references, and the tire size already mounted on the car are all useful checkpoints. That small amount of verification prevents choosing the right era of tire in the wrong section width.

1940 Nash tires in 700-16 are available in both blackwall and wide whitewall styles. The blackwall choices include Avon and BFGoodrich, while wide whitewall versions are offered by Lester and Firestone. All of these are bias-ply options, so the visual decision is about sidewall presentation rather than choosing between bias-ply and radial construction.

That choice has a strong effect on the finished look of a prewar Nash. Blackwalls give a more restrained appearance, while a wide whitewall leans into the formal, upscale character many restorers want from a 1940 Ambassador. If the car is being prepared for judged events, sidewall style should be matched to the car's intended presentation and any applicable marque or event standards.

Current 700-16 offerings for 1940 Nash come from Lester, Avon, BFGoodrich, and Firestone. Those brands cover both blackwall and wide whitewall versions within the same basic bias-ply size. The available lineup gives Ambassador owners a mix of visual styles and some variation in rated load and speed information depending on the specific tire.

Brand choice on a prewar car often comes down to the appearance you want and the level of period flavor you are after, not just the size molded into the sidewall. A buyer comparing 1940 Nash tires should look at brand, sidewall style, and any stated load or speed markings together. That approach keeps the tire aligned with both the car's character and the way it will be driven.

For the 1940 Nash in 700-16, the BFGoodrich offering is a blackwall bias-ply tire with a listed maximum load of 1900 pounds at 36 psi and a recommended rim width range of 4.50 to 5.50 inches. The Firestone offering is a 4.00-inch whitewall bias-ply tire with a listed maximum load of 1800 pounds at 36 psi and the same 4.50 to 5.50-inch rim width range.

The practical difference is mostly visual first and specification second. BFGoodrich gives a blackwall look, while Firestone delivers a wide whitewall appearance that changes the stance and period character of the car. Since both share the same rim width range and basic construction type, the decision usually comes down to whether your 1940 Nash is being finished with a more understated or more formal prewar presentation.

Available 700-16 tires for 1940 Nash list a rim width range of 4.50 to 5.50 inches on BFGoodrich and Firestone offerings. All listed 1940 Nash sizes use a 16-inch rim diameter, which is the critical first fitment check before considering width. That gives Ambassador owners a concrete range to compare against an existing wheel when evaluating 700-16 fitment.

Rim width matters because the same diameter wheel can still be wrong for a given tire if the width falls outside the acceptable range. Before mounting tires on a 1940 Nash, measure the actual wheel or confirm its specifications through a trusted restoration source. That is especially important on older cars that may have had wheels swapped during decades of service.

The listed 1940 Nash products do not carry tube-type or tubeless markings in a way that creates a universal year-make rule across every offering shown here. What remains consistent is that both 6.25-16 and 700-16 belong to the prewar bias-ply era, where wheel design and tire specification should be checked together rather than assuming one setup fits all combinations.

For a 1940 Nash, the smartest approach is to inspect the actual wheel and verify the sidewall marking of the exact tire being considered before final installation. Original-style prewar wheels often call for more attention to tube and flap needs than later one-piece tubeless designs. Matching the tire's construction and marking to the wheel avoids setup problems that do not show up from size alone.

Both tire sizes used on the 1940 Nash Ambassador are built around a 16-inch rim diameter, so original wheels of the correct diameter can generally accept either size at the diameter level. Available 700-16 products also show a 4.50 to 5.50-inch rim width range, which is an important secondary check when evaluating any original wheel.

That means a diameter match by itself is not the whole answer. A 1940 Nash owner should verify the wheel's actual width and condition before assuming it is suitable for both sizes. On a prewar car, original wheels may have seen repairs, corrosion, or substitutions over the years, and those factors matter just as much as the stamped diameter when preparing the car for use.

A stored 1940 Nash should be kept in a cool, dry space away from direct sunlight, electric motors, battery chargers, furnaces, and other ozone-producing equipment that can age sidewalls. Because 1940 Nash fitments here are bias-ply, they are especially prone to flat-spotting during long static periods. Clean floors, stable temperatures, and proper inflation help reduce stress on both tire casing and wheel.

If the car will sit for an extended season, move it periodically or support it in a way that reduces constant load on one contact patch. Bias-ply tires can take a temporary set more readily than modern radials, especially in collector use where the car is parked more than it is driven. Good storage habits preserve ride quality and appearance as much as they preserve tread.

On a 1940 Nash, tire age is usually more important than tread wear because collector cars often see limited annual mileage. A good rule is to begin evaluating tires carefully once they reach the five- to seven-year range and to treat around ten years as the point where replacement deserves serious consideration, even if the tread still looks usable. The DOT date code on the tire is the reference point for age.

That approach helps owners avoid relying on visual appearance alone. A prewar car may spend years indoors and still develop age-related hardening, cracking, or reduced resilience that is not obvious at first glance. If a 1940 Nash is used mainly for shows, tours, or occasional weekend drives, calendar age remains the best guide for deciding when the tires deserve closer scrutiny or replacement.

Tires on a 1940 Nash should be checked before every drive and again before any longer outing. Look for sidewall cracking, cuts, bulges, uneven wear, and any sign that the tire is losing pressure between uses. On a collector car from this era, the spare should be inspected too, since it may be as old as the road tires or older.

Frequent inspection matters because a lightly used prewar car can hide tire problems that would become obvious faster on a daily driver. A careful walk-around before each drive gives you time to catch aging rubber, wheel issues, or valve-stem problems before the car is out on the road. That habit is one of the easiest ways to make occasional use of a 1940 Nash more predictable and enjoyable.

The 1940 Nash Ambassador belongs to the prewar American era when bias-ply construction was the standard type of passenger-car tire. The sizes associated here with the Ambassador are 6.25-16 and 700-16, both bias-ply and both built for 16-inch rims. Original-equipment branding could vary by market, supply, and production practice, so the most dependable restoration baseline is size, construction type, and correct visual style.

For most restorations, that means starting with a bias-ply tire in the proper 16-inch fitment and then choosing the sidewall look that matches the car's intended presentation. Owners pursuing a highly exact factory restoration should compare surviving literature, original photos, and marque-club guidance before finalizing the tire. That extra step is worthwhile on a 1940 Nash because small visual details strongly influence an authentic prewar appearance.

Correct tire fitment matters on a 1940 Nash because judges and knowledgeable enthusiasts often notice whether the size, construction type, and sidewall style suit the period. A prewar Ambassador is expected to wear a bias-ply tire with proportions and appearance consistent with 1940 practice. An obviously modern construction or an out-of-period sidewall treatment can distract from an otherwise careful restoration.

The level of scrutiny depends on the event. Local shows may be more relaxed, while marque-specific judging can be much stricter about visual authenticity. If your 1940 Nash is being prepared for serious competition, verify not only the basic size but also whether a blackwall or wide whitewall is more appropriate for the car's intended class, then compare that against the standards used by the hosting organization.

For the 1940 Nash in 700-16, Lester offers a wide whitewall bias-ply tire in its classic bias-ply line, while Firestone offers a 4.00-inch whitewall bias-ply version. Both share the same nominal size and preserve the period-correct bias-ply construction expected on a prewar Ambassador. The visible difference is the whitewall treatment and the brand identity presented on the restored car.

That distinction matters most when the car's finish and presentation are being judged as a complete period ensemble. One owner may prefer the exact look of a broad whitewall to complement formal prewar styling, while another may be trying to mirror a specific restoration reference. Comparing the visual effect of the sidewall against the car's paint, trim, and intended authenticity target is usually the deciding factor.

1940 Nash tires can be suitable for highway use when they are in good condition, properly installed, and matched to the way the car is actually driven. The listed 700-16 Avon tire carries an L speed rating, which corresponds to a 75 mph ceiling, while the other bias-ply offerings shown do not list a speed letter in the same way. On a prewar car, the condition of the vehicle itself often matters as much as the tire's theoretical limit.

A 1940 Nash should be driven within the abilities of its brakes, suspension, steering, and overall mechanical condition rather than by tire rating alone. Bias-ply tires also have a different on-road feel from later radials, especially in tracking and response. If the car is used on modern roads, a conservative cruising approach and a full pre-drive inspection are more important than chasing modern traffic speeds.

Inflation pressure for a 1940 Nash should follow the vehicle's factory guidance first, with the tire manufacturer's stated load-and-pressure information used as the operating limit for the specific reproduction tire. Among available 700-16 options, BFGoodrich lists 1900 pounds at 36 psi and Firestone lists 1800 pounds at 36 psi. Those figures describe the tire's rated load relationship to pressure and should not be treated as a blanket setting for every size or product.

The practical approach is to begin with the carmaker's recommendation for the vehicle, then confirm that the selected tire's rated pressure and load parameters are being respected. Do not transfer a pressure figure from one brand or size to another simply because the rim diameter matches. A 1940 Nash rides and steers best when pressure is chosen with both the vehicle and the exact tire in mind.

Before a longer trip in a 1940 Nash, inspect each tire for cracks, cuts, bulges, irregular wear, and proper inflation, and make sure the spare is serviceable as well. Verify that wheel hardware is secure and that the tires have not developed storage-related flat spots. On a prewar car, that tire check should happen alongside a broader review of fluids, belts, cooling condition, brakes, and steering components.

A longer drive places more sustained heat and load into a vintage tire than a short local outing, so small issues become more important. Giving the tires a close inspection before departure reduces the chance that an age-related defect or slow leak turns into a roadside problem. For a 1940 Nash, thoughtful preparation is part of driving the car responsibly and enjoying it with confidence.