1940 Buick Tire Fitment Guide

1940 Buick vehicles use three tire sizes across five model lines. The 40 Special and 50 Super use 650-16, the 60 Century uses 700-15, and the 80 Series and 90 Series use 750-16. The 650-16 and 750-16 sizes both fit 16-inch rims, while 700-15 fits a 15-inch rim. Where rim-width guidance is available, 650-16 is paired with 4.50- to 5.00-inch rims, 700-15 with 5.00- to 5.50-inch rims, and 750-16 with 5.00- to 6.00-inch rims.

That means 1940 Buick fitment is model-specific, not one-size-fits-all across the entire make. A Special or Super owner should not assume Century or senior-series tires will interchange simply because the cars are all 1940 Buicks. Start by confirming the exact series designation on the car, then verify the wheel diameter and compare the actual rim against the width range used by the tire you are considering.

On a 1940 Buick, 650-16 is a numeric bias-ply tire size. The 6.50 designation identifies the tire's nominal section-width class in period sizing, and the 16 identifies the wheel diameter in inches. On this Buick application, 650-16 is used on the 40 Special and 50 Super, and available tires in this size are bias-ply designs offered in blackwall and wide whitewall form.

Modern buyers sometimes mistake the first number for tread width or assume it translates directly into a metric size, but it is really part of an older sizing system used on American cars of the period. If your 1940 Buick is a Special or Super, 650-16 is the fitment to match first, and then the next choice becomes appearance: blackwall for a plainer, more understated look or wide whitewall for a fuller prewar luxury presentation.

No, 1940 Buick models do not all use the same tire size. The 40 Special and 50 Super share 650-16, the 60 Century stands alone with 700-15, and the 80 Series and 90 Series share 750-16. That split also means wheel diameter changes within the lineup, since the Century uses a 15-inch rim while the others here use 16-inch rims in different size classes.

This matters because a buyer who only knows the year and make can easily land on the wrong tire if the model is not confirmed first. Buick's 1940 range covered entry-level, midrange, and senior cars, so tire sizing followed the car's place in the lineup. If you are still sorting out the exact series, check the body tag, registration records, or a Buick club reference before moving on to sidewall style or brand preference.

1940 Buick tires are available in both blackwall and wide whitewall styles across the sizes used by the model range. The 650-16 offerings for the 40 Special and 50 Super include both blackwall and wide whitewall choices, 700-15 for the Century is also offered in both styles, and 750-16 for the 80 and 90 Series comes in blackwall and wide whitewall versions as well.

The practical choice comes down to how you want the car to present. Blackwalls suit more restrained, service-replacement, or lower-profile appearances, while wide whitewalls are often the visual cue collectors want on a restored prewar Buick, especially on more upscale body styles. If originality matters for show use, compare your chosen sidewall style against period Buick photography and event judging standards rather than assuming every 1940 Buick was delivered the same way.

Several brands cover 1940 Buick fitments, but the brand mix changes by size. In 650-16, available makers include BFGoodrich, Coker Classic, Firestone, and Garfield. In 700-15, the available brands are Firestone, BFGoodrich, and STA. In 750-16, the available brands are Firestone, Lester, and BFGoodrich. All of the available fitments here are bias-ply tires rather than radials.

That variety gives owners room to choose around appearance, brand preference, and the character of the tire line while still staying within a period-appropriate construction. A Century owner, for example, is choosing among a different brand set than an 80 or 90 Series owner. Once you know the correct size for your Buick, compare the brands available in that size instead of assuming every name offered elsewhere in the 1940 Buick range also applies to your model.

In 750-16 for 1940 Buick applications, both Firestone and BFGoodrich offer bias-ply tires, but the available specifications are not identical. Firestone appears in blackwall and wide whitewall versions, with listed load figures of 1660 pounds at 40 psi and a 5.00- to 6.00-inch rim-width range. BFGoodrich offers a wide whitewall version with a listed load figure of 1850 pounds at 48 psi and the same 5.00- to 6.00-inch rim-width range.

The takeaway is not that one choice automatically suits every 80 or 90 Series owner better than the other, but that the details deserve a close look before you choose. If you are comparing two 750-16 products, look at sidewall style first, then compare the rated load-and-pressure pairing and the wheel width on the car. That is especially worthwhile on larger senior Buicks, where the tire contributes heavily to both stance and overall period presentation.

Rim-width guidance varies by 1940 Buick tire size. The 650-16 tires used on the 40 Special and 50 Super are paired with 4.50- to 5.00-inch rims. The 700-15 tires used on the 60 Century are paired with 5.00- to 5.50-inch rims. The 750-16 tires used on the 80 Series and 90 Series are paired with 5.00- to 6.00-inch rims.

That range is important because correct tire size alone does not guarantee the wheel is the right match. A Buick that has had wheels swapped over the years can still carry the correct nominal diameter but be wrong in width. Before settling on a specific tire, measure the wheel or confirm it against a trusted wheel reference so the sidewall profile and bead seating match the fitment the tire was built around.

Original 1940 Buick wheels cannot be treated as universal across all three tire sizes because the lineup uses both 15-inch and 16-inch rim diameters. The 40 Special and 50 Super use 650-16 on 16-inch rims, the 60 Century uses 700-15 on 15-inch rims, and the 80 Series and 90 Series use 750-16 on 16-inch rims. Even among the 16-inch applications, the listed rim-width ranges are different between 650-16 and 750-16.

In practice, that means wheel interchange questions should be approached carefully rather than assumed. A 16-inch Buick wheel may share diameter with another model but still differ in width suitability for the tire size you want to run. If your car has replacement wheels, mixed wheels, or a long restoration history, confirm the actual wheel dimensions before choosing tires simply by series name.

A stored 1940 Buick should be kept in a cool, dry, dark space away from direct sunlight, electric motors, battery chargers, furnaces, and other ozone-producing equipment that can age rubber prematurely. Keeping the tires clean and properly inflated helps the carcass hold its shape during periods of inactivity. Because 1940 Buick fitments here are all bias-ply, they are more prone to temporary flat-spotting during long static storage than a modern radial would be.

For longer layups, move the car periodically so the tires are not loaded in the same position for months at a time, or support the vehicle in a way that reduces sustained tire loading if appropriate for your storage plan. When the car returns to use, let the tires warm gradually on the road before judging ride quality. Collector cars that sit beautifully can still age their tires quickly if the storage environment is harsh.

Tires on a 1940 Buick are usually better judged by age and condition than by mileage alone. Collector cars often accumulate very few miles, yet the rubber, casing, and sidewall still age over time. A good rule is to begin evaluating tires closely once they are in the five- to seven-year range and to treat around ten years as the point where replacement deserves serious consideration, even if tread depth still looks serviceable.

Check the date code on the tire and weigh that age against how the car has been stored and driven. A lightly used prewar Buick that has spent years parked in warm, bright, or ozone-rich conditions can have older-looking tires than a car driven more regularly and stored well. If you are uncertain whether age has overtaken appearance, err on the side of replacement before asking the car to do regular road duty.

Tires on a 1940 Buick should be inspected before every drive and again before any longer outing. Look for sidewall cracking, cuts, bulges, exposed cords, uneven wear, and signs that pressure has dropped since the last use. On a low-mileage collector Buick, age-related deterioration often matters more than tread wear, so visual inspection is a meaningful part of routine ownership rather than a once-a-season check.

Make that inspection part of a broader pre-drive walkaround. Verify that the spare is sound, the valve stems look healthy, and the tire is sitting evenly on the wheel with no sign of bead disturbance. A car from 1940 asks more of the owner in general, and catching tire issues early is one of the simplest ways to avoid turning a pleasant local drive or tour event into a preventable roadside problem.

A 1940 Buick 40 Special would have been fitted in period with bias-ply tires, since that was the standard construction for American passenger cars of the era. Within the 1940 Buick range covered here, the 40 Special uses the 650-16 size, the same fitment shared with the 50 Super. No single original-equipment brand should be assumed across every car, body style, or market delivery without marque-specific confirmation.

For a restoration, the safest authenticity path is to match the correct size first, then choose a sidewall style that fits the way your car was built and presented. Factory photos, period sales literature, and Buick club judging references are worth consulting if the car is headed for serious show use. That extra step helps settle details like blackwall versus whitewall presentation without guessing from another 1940 Buick series.

Correct tire fitment matters on a 1940 Buick because judges and knowledgeable enthusiasts notice size, construction, and sidewall presentation quickly. A Century wearing a tire meant for a Special, or a senior 90 Series wearing a visibly undersized fitment, changes the stance and can undermine an otherwise careful restoration. On prewar cars, bias-ply construction is also part of the visual and historical character many judged events expect to see.

Even when a car is not headed for concours judging, the right tire fitment helps the Buick sit and look the way its designers intended. Show standards vary, so event rules and Buick marque clubs remain the best places to confirm how closely originality will be evaluated. If authenticity is central to the project, choose the correct size for the exact series first and let sidewall style support the final presentation.

For the 1940 Buick 60 Century in 700-15, Firestone and BFGoodrich both offer bias-ply fitments with wide whitewall options, and Firestone also appears in a blackwall version. The listed load figure on the Firestone and BFGoodrich examples is 1700 pounds at 32 psi, and both use the same 5.00- to 5.50-inch rim-width range. An STA 700-15 option also exists in blackwall form, but it belongs to a different series character than the classic passenger-car whitewall offerings.

That makes the decision less about chasing a major dimensional difference and more about selecting the appearance and product line that suits your Century restoration. If the car is being finished to a formal prewar look, the whitewall choices will usually be the first comparison point. If the goal is a plainer road-use presentation, the blackwall path may make more sense while still keeping the correct size and period construction.

1940 Buick tires in these fitments are bias-ply products, and the examples listed here do not show modern speed-rating letters such as S, T, or H. That means the tire choice should be approached with the understanding that prewar-style bias-ply behavior differs from modern radial expectations in tracking, steering feel, and response to grooves or uneven pavement. On a properly maintained car, the practical limits of a 1940 Buick's brakes, steering, suspension, and overall mechanical condition may matter more than raw tire capability during normal highway use.

Highway use is realistic when the tires are in sound condition, correctly inflated, and matched to the correct wheels, but it should be approached with period-appropriate expectations. A 1940 Buick is best driven smoothly, with moderate speeds and generous following distance, especially on long trips. Think of the tire as one part of an older system: if the car has aging suspension parts, poor alignment, or stale brake components, replacing tires alone will not make highway travel feel modern.

Inflation pressure on a 1940 Buick should follow the vehicle's original factory guidance first, with the tire's rated load-and-pressure information used as the product limit rather than a universal set point. Among the available fitments here, 650-16 examples are listed at 1580 pounds at 32 psi, 700-15 examples at 1700 pounds at 32 psi, and 750-16 examples at either 1660 pounds at 40 psi or 1850 pounds at 48 psi depending on the tire.

Those figures should not be transferred from one Buick size to another or from one product line to another without checking the tire itself. A senior-series 750-16 and a Special's 650-16 are not interchangeable in pressure logic simply because both belong to 1940 Buick applications. Use the Buick owner's literature or trusted factory reference for the starting point, then confirm that your chosen tire's own sidewall and manufacturer guidance support that operating range.

Before a longer drive in a 1940 Buick, inspect each tire for visible cracking, cuts, bulges, uneven wear, embedded debris, and any sign that the sidewall has aged beyond confidence. Verify cold inflation pressure, confirm the spare is usable, and make sure each valve stem is intact and not weather-checked. Since the Buick lineup here uses model-specific sizes, it is also wise to confirm that all four road tires actually match the correct size for the car rather than relying on what a previous owner fitted.

A longer drive is also the right moment to think beyond the tires themselves. Prewar Buicks reward careful preparation, so include brakes, cooling system, wheel bearings, and steering in the pre-trip routine. Tires can only do their job if the rest of the chassis is healthy. When a 1940 Buick is sorted properly, the road experience is far more relaxed than many first-time owners expect, but preparation is what makes that confidence possible.