1951 Buick 70 Roadmaster Tires

The primary tire size for the 1951 Buick 70 Roadmaster is 800-15. This is a numeric bias-ply size used on a 15-inch rim, and the covered 8-cylinder sub-model uses that same fitment rather than a different primary size.

That means the main task is choosing the right tire within the 800-15 size rather than sorting through multiple factory-type fitments. Owners should still confirm the actual wheel on the car, especially if it has been changed over the years, and decide whether the goal is a traditional bias-ply presentation or a radial-equivalent alternative.

The 1951 Buick 70 Roadmaster uses a 15-inch rim with its primary 800-15 tire fitment. Product options in this size are built for 15-inch wheels, and the available bias-ply examples show a rim-width specification of 6.00 to 6.50 inches.

Rim diameter is the first detail to confirm before selecting tires, because a 15-inch tire must match a 15-inch wheel. Width matters too, especially if the car has replacement wheels, since construction choice and tire profile can change how the tire sits on the rim and how it clears suspension and body components.

An 800-15 is a vintage numeric bias-ply tire size. The 800 identifies the tire’s nominal width class, commonly understood as about 8.00 inches, while the 15 identifies the wheel diameter in inches.

This older sizing format is different from modern metric radial sizes, so it helps to treat it as a period tire designation rather than trying to compare it loosely to a current size by width alone. When considering alternatives, use actual equivalent sizes intended for 800-15 and verify wheel width and vehicle clearance before making a change.

For the 1951 Buick 70 Roadmaster, 800-15 is the primary bias-ply tire size. The available products in that original-style size are bias-ply construction, which preserves the traditional sidewall shape and period presentation associated with a large early-1950s Buick.

That matters because a bias-ply tire and a radial equivalent are not the same construction even when they are intended to occupy a similar fitment space. Owners deciding between them should think about restoration goals, confirm the wheel setup on the car, and check clearance carefully before moving away from the original-style construction.

Radial equivalents for 800-15 include 225R15 as an 80-series metric radial, P235/75R15 as a P-metric 75-series radial, P235/70R15 as a P-metric 70-series radial, and 800R15 as a bias-look radial. These are distinct equivalent formats rather than duplicate versions of the same tire.

The practical difference is that they use different sizing conventions and can present a different profile or appearance on the car. A 6-8 inch rim-width range is associated with these equivalents, so the wheel should be measured and the car checked for clearance before treating any of them as a workable alternative.

An 800R15 bias-look radial is available as an equivalent for the 1951 Buick 70 Roadmaster’s original 800-15 size. It is intended for owners who want a radial alternative while keeping a more traditional visual presentation than a modern-looking metric size might provide.

That makes it a useful option for a car where appearance still matters, but it should not be treated as an automatic swap. Wheel width, overall tire dimensions, and clearance at the fenders and suspension all deserve a careful check, especially on a large collector car that may have seen wheel or suspension changes over time.

Start with the correct primary size, 800-15, and make sure the wheel is a 15-inch rim with suitable width for the tire being considered. From there, the main choices are construction and appearance, since the available options in this size focus on bias-ply wide whitewall tires.

The Roadmaster’s scale makes visual balance especially important, so sidewall treatment can change the car’s overall presentation as much as the tire brand or series. Buyers should also compare rim-width compatibility, load specification, and whether the car is being kept as a restoration-oriented cruiser or evaluated for a radial-equivalent setup.

The available 800-15 tires for the 1951 Buick 70 Roadmaster use a wide whitewall sidewall style. Within that presentation, the visible distinction is whitewall width, with both 2.50-inch and 3.00-inch whitewall versions offered in the same Coker Classic bias-ply series.

That gives the buyer an appearance decision more than a fitment decision, since both are the same primary size and construction. A narrower or wider whitewall can subtly change how formal or dramatic the Roadmaster looks, so the right choice usually depends on the restoration theme and the visual character desired from the finished car.

The available 800-15 options are closely related in construction and series, so the most meaningful difference is whitewall width. Both choices are bias-ply Coker Classic tires with the same 15-inch rim diameter, similar rim-width specification, and the same stated load capacity of 1800@32 psi.

That means the decision comes down to the appearance you want on the car rather than chasing a completely different fitment. It is still worth confirming that the wheel width matches the tire specification and that the rest of the vehicle setup has not been altered before settling on the whitewall treatment that best suits the Buick.

A period-style starting point for the 1951 Buick 70 Roadmaster is the original-size 800-15 bias-ply tire. That keeps the car in its traditional sizing format and preserves the tall-sidewall, early-1950s presentation that suits a large Buick from this era.

For many restorations, the bigger visual choice is the whitewall treatment rather than the basic size itself. Exact originality can vary by build and owner preference, so buyers seeking a highly specific historical appearance should compare the tire choice with marque references, period photography, or other vehicle-specific documentation before finalizing the look.

Tire construction changes more than ride feel on a restored 1951 Buick 70 Roadmaster; it also changes the car’s visual character. An 800-15 bias-ply tire maintains the vintage numeric sizing format and a traditional sidewall profile, while a radial equivalent can give the car a more modern tire presentation.

That difference becomes especially noticeable on a large, formal car where whitewall proportion and sidewall shape contribute heavily to the finished stance. Owners who want a restoration-oriented appearance often begin with bias-ply sizing, while those considering a radial should weigh how much modern construction may alter the Buick’s period look.

Yes, modifications can affect tire fitment on a 1951 Buick 70 Roadmaster even when the nominal tire size stays close to stock. Aftermarket wheels, altered rim width, suspension changes, ride-height changes, or bodywork repairs can all influence how an 800-15 tire or a radial equivalent sits and clears.

That is why the actual wheel and vehicle setup should be checked before selecting a tire purely by the model name. A car that has been lowered, widened, or fitted with replacement wheels may need closer attention to clearance at the fenders, steering components, and suspension than an unmodified Roadmaster.

Before putting a 1951 Buick 70 Roadmaster back on the road with new tires, inspect the wheels for proper diameter and condition, confirm that the tires are seated correctly, and check inflation pressure. It is also wise to look over the valve stems, lug hardware, and visible clearance around the suspension and body.

A collector Buick should also be evaluated as a system rather than just a tire change. Steering components, shocks, brakes, and wheel bearings can all influence how the car behaves once fresh tires are installed, and a short, careful road test is a better first outing than immediately heading out on a longer drive.

800-15 tires on a collector 1951 Buick 70 Roadmaster should be maintained with regular pressure checks, visual inspections, and attention to storage conditions. Because older collector cars may spend long periods parked, sidewall cracking, flat spotting, air loss, bulges, and tread deterioration deserve closer monitoring than they might on a daily driver.

Good maintenance also means protecting the tires from prolonged sunlight, heat, moisture, and ozone sources when the car is stored. Even a low-mileage Roadmaster benefits from periodic inspection and movement, since tire condition depends on age and environment as much as tread wear on a seldom-driven collector vehicle.