1949 Buick 70 Roadmaster Tires

The 1949 Buick 70 Roadmaster uses 820-15 as its primary tire size. This is a numeric bias-ply size mounted on a 15-inch rim, and the covered 8 Cyl. sub-model uses that same fitment.

That makes the main choice less about finding multiple factory-era sizes and more about choosing the right version of 820-15 for the car. Before replacing tires, it is still smart to confirm the actual wheel diameter on the vehicle, especially if the Buick has been stored for years or updated with later wheels during an earlier restoration.

The primary 820-15 fitment for the 1949 Buick 70 Roadmaster uses a 15-inch rim diameter. That rim diameter is central to both traditional bias-ply replacement and any radial-equivalent comparison built around the same nominal wheel size.

Rim diameter is only part of the picture, though. Some 820-15 products are built around 6.00-6.50 inch rim widths, while certain specialty versions call for wider ranges, so the actual wheel width should be checked before choosing among available tires. That matters even more if the car no longer has its original-style wheels.

820-15 is a vintage numeric bias-ply tire size. The 820 portion refers to an approximate nominal section width of 8.20 inches, while the 15 identifies the rim diameter in inches.

Modern buyers often expect a metric size with an aspect ratio, but this older format works differently and reflects the era of the car. On a 1949 Buick 70 Roadmaster, understanding that size code helps separate the original-style bias-ply fitment from modern radial equivalents, which use different naming systems and should be checked carefully before substitution.

For the 1949 Buick 70 Roadmaster, 820-15 is a bias-ply tire size. The primary fitment for this vehicle is built around that traditional construction, which matches the period sizing system and the kinds of tire profiles commonly seen on large postwar American cars.

That does not prevent a radial alternative from being considered, but it does mean bias-ply remains the starting point for restoration-oriented selection. Owners deciding between constructions should compare wheel width, overall dimensions, and the kind of road use the Buick will see, rather than assuming every tire with the same rim diameter behaves or presents the same way.

Radial equivalents for 820-15 include 235R15, P235/75R15, P255/70R15, and 820R15. Those represent an 80-series metric radial, a 75-series P-metric radial, a 70-series P-metric radial, and a bias-look radial equivalent, respectively.

Each option approaches the original size from a slightly different sizing convention and visual profile. A recommended rim-width range of 6-8 inches is associated with those equivalents, but that does not make them automatic substitutions. Wheel width, tire dimensions, steering clearance, and the car’s current ride height or suspension condition should all be confirmed before moving away from the original bias-ply format.

A bias-look radial equivalent is available for the 1949 Buick 70 Roadmaster in size 820R15. That option is meant for owners who want a radial-format alternative while keeping a more traditional visual presentation than a modern-looking metric tire might provide.

Even with that more vintage appearance, it should still be treated as a radial alternative rather than the same thing as the original 820-15 bias-ply fitment. The wheel setup matters here, especially width and clearance, and the finished result should be checked against the Buick’s stance and fender space before the switch is finalized.

Start with the correct 820-15 size and the 15-inch wheel, then decide whether the car calls for a traditional bias-ply presentation or a radial-equivalent approach. For a period-style Roadmaster, construction and sidewall treatment usually shape the decision as much as the size itself.

Beyond appearance, compare the rim-width requirements of the specific tire, along with load figures where they are given. A large late-1940s Buick benefits from a tire that suits both the wheel and the car’s intended use, whether that means show presentation, occasional touring, or a setup that leans more toward specialty or performance-style products.

820-15 tires for the 1949 Buick 70 Roadmaster are available in blackwall, narrow whitewall, and wide whitewall styles. That gives the car a broad range of visual directions, from a restrained driver-quality look to a more formal postwar luxury presentation.

Sidewall choice affects the finished personality of the Buick more than many buyers expect. A blackwall keeps things understated, while narrow and wide whitewalls move the car toward a stronger restoration-oriented appearance. The right choice depends on how the car is being finished rather than on a universal rule, especially when period-style taste varies between owners and restoration goals.

The 1949 Buick 70 Roadmaster has 820-15 tire options from BFGoodrich, Firestone, US Royal, Universal Vintage Tire, and Avon. Those choices include several classic bias-ply series along with differing sidewall treatments and, in some cases, more specialized product types.

Brand alone should not be the only filter. It helps to compare the tire series, the sidewall style, the rim-width range, and whether the tire is meant for traditional street use or a more specialized application. That approach usually produces a better match for the Buick’s appearance and use than simply selecting the first recognizable name.

A period-style 1949 Buick 70 Roadmaster usually starts with the original-format 820-15 bias-ply size. That keeps the car in the right visual family for a large postwar Buick and preserves the tall, traditional tire presentation associated with the era.

From there, the real choice is often sidewall treatment and brand character rather than size. Blackwall, narrow whitewall, and wide whitewall versions are all available, so the right fit depends on how formal or restrained the finished car should look. If exact originality matters, marque-specific restoration references remain the best place to verify detail-level appearance decisions.

Tire construction changes more than ride feel on a restored 1949 Buick 70 Roadmaster; it also changes the visual character of the car. An 820-15 bias-ply keeps the traditional vintage sizing format, while a radial equivalent can introduce a different profile or a more modern sizing appearance.

That difference is especially noticeable on a full-size late-1940s Buick, where the tire contributes heavily to stance and period impression. A bias-look radial can narrow the visual gap for owners wanting a radial alternative, but the wheel and clearance setup still needs to be checked so the car’s appearance and fitment stay in balance.

Modifications can absolutely affect tire fitment on a 1949 Buick 70 Roadmaster. Even though the primary size is 820-15 on a 15-inch rim, later wheel swaps, altered wheel widths, suspension changes, or brake updates can change what works safely and cleanly on the car.

A Buick from this era may have been changed decades ago, so visual inspection matters just as much as the catalog size. The wheel diameter and width should be verified first, then steering and fender clearance should be checked with the car at normal ride height. That is especially important before trying a radial equivalent or a specialty tire with different wheel-width needs.

Before driving a 1949 Buick 70 Roadmaster on new tires, inspect the wheels for correct diameter and condition, confirm the tires are seated properly, and check inflation pressure, lug hardware, and visible clearance around the fenders and steering components. A short initial drive should be followed by another visual check.

On a collector Buick, it also helps to inspect suspension bushings, shocks, steering play, and brake condition before asking the car to track properly on fresh tires. New tires cannot compensate for mechanical looseness elsewhere, and an older car that has sat for long periods may reveal issues only after it is back on the road.

820-15 tires on a collector 1949 Buick 70 Roadmaster should be kept properly inflated, inspected regularly for cracking, cuts, bulges, and uneven wear, and protected from long exposure to sunlight, moisture, and ozone sources during storage. Collector cars that see limited miles still need routine tire attention.

Low annual mileage can hide aging issues, so tread depth alone is not enough. It is wise to check for air loss, flat spotting after storage, and any change in steering feel once the car is back in motion. Consistent inspection is especially important on a heavy postwar car where tire condition has a direct effect on road manners.