1958 Buick 70 Roadmaster Tires

The 1958 Buick 70 Roadmaster uses an 800-15 tire size. This is a numeric bias-ply size used on a 15-inch rim, and the covered 8-cylinder Roadmaster sub-model shares that same primary fitment.

That means the size question is usually simpler than on vehicles with multiple factory fitments. The next step is confirming the car still has the proper 15-inch wheels and then deciding whether the goal is a traditional bias-ply tire with a wide whitewall look or a radial-equivalent alternative that should be checked carefully for wheel width and clearance.

The 1958 Buick 70 Roadmaster uses a 15-inch rim with its primary 800-15 tire fitment. That rim diameter is part of the original tire size designation, and it is the first wheel measurement to confirm before replacing tires.

Rim diameter alone does not settle the whole fitment question on an older car, especially if the wheels have ever been changed. Checking the actual wheel width also matters, particularly if a radial equivalent is under consideration, because the recommended radial-equivalent rim-width range for this size starts at 6 inches and extends to 8 inches.

An 800-15 is a vintage numeric bias-ply tire size. The 800 indicates an approximate nominal section width of 8.00 inches, while the 15 identifies the wheel diameter in inches.

That older sizing system is different from modern metric radial sizes, so it helps to read it as both a fitment code and a clue to the car's original tire character. On a 1958 Roadmaster, keeping the 800-15 format preserves the traditional look, while any move to a radial equivalent should still be checked against the wheel and the car's actual clearance.

For the 1958 Buick 70 Roadmaster, 800-15 is the primary bias-ply tire size. It belongs to the older numeric sizing system used on many American cars of this period and is the traditional construction associated with this fitment.

Staying with a bias-ply tire keeps the vintage sizing format and traditional appearance that many restoration-minded owners want. A radial alternative can still be considered, but the change should start with the actual wheel dimensions on the car, along with a careful look at clearance around the fenders, steering, and suspension.

Radial equivalents for 800-15 include 225R15, P235/75R15, P235/70R15, and 800R15. 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 gives the buyer a different sizing convention and profile approach while staying in the same general replacement conversation. The recommended rim-width range for these radial equivalents is 6 to 8 inches, so wheel width should be confirmed first, followed by a check of tire dimensions, steering sweep, and body clearance before making the change.

A bias-look radial equivalent is available for the 1958 Buick 70 Roadmaster in size 800R15. That option is meant for buyers who want a radial-format alternative while keeping a more traditional tire presentation than a modern metric sidewall usually provides.

It is still important to treat 800R15 as an equivalent choice rather than an automatic replacement. The wheel should be measured for width, the 15-inch rim confirmed, and the car checked for fender and steering clearance, especially on a large late-1950s body where stance and sidewall appearance matter almost as much as the fitment itself.

Start with the primary fitment itself: the 1958 Buick 70 Roadmaster uses an 800-15 bias-ply tire on a 15-inch rim. From there, the main selection factors are whether the car is being kept in a traditional bias-ply configuration, what whitewall presentation looks right on the car, and whether the wheel width matches the tire being considered.

A Roadmaster's size and styling make appearance especially important, so the difference between a 2.50-inch and 3.00-inch wide whitewall can influence the whole look of the car. Buyers should also compare product details such as rim-width specification, load capacity, and overall intended use before settling on a final choice.

Available 800-15 products for the 1958 Buick 70 Roadmaster use a wide whitewall sidewall style. Within that presentation, the visible difference comes from whitewall width, with both 2.50-inch and 3.00-inch whitewall versions offered in the same Coker Classic Bias Ply series.

That choice affects the car's visual balance more than its fitment, but it can make a major difference on a large, highly styled 1958 Buick. Owners aiming for a particular period-style presentation often choose the whitewall width that best matches the car's trim, stance, and restoration theme rather than treating both versions as identical from an appearance standpoint.

The available 800-15 products for the 1958 Buick 70 Roadmaster are offered in the Coker Classic Bias Ply series. That series keeps the vehicle in its traditional bias-ply construction and focuses on the broad whitewall styling that suits a luxury Buick of this era.

Because the series is consistent across the current product choices, the decision shifts to details within that family rather than moving between very different tire personalities. Whitewall width, wheel compatibility, and whether the car is being restored, shown, or regularly driven are the practical factors that separate one 800-15 choice from another.

For a period-style 1958 Buick 70 Roadmaster, the 800-15 bias-ply fitment is the natural starting point because it preserves the vintage sizing format and the traditional profile expected on a large late-1950s Buick. The available Coker Classic Bias Ply options also keep the focus on wide whitewall presentation.

The finer choice is usually the whitewall width that best suits the car's trim and restoration theme. Buyers pursuing exact historical accuracy should compare the tire choice with marque references, restoration photos, or other vehicle-specific documentation, since a period-style tire can be appropriate visually without claiming a precise factory-original specification.

Tire construction changes the visual character of a restored 1958 Buick 70 Roadmaster as much as it changes the driving feel. An 800-15 bias-ply keeps the older sizing format and the traditional sidewall presence associated with this generation of full-size Buick.

A radial equivalent can alter that presentation, especially when modern metric sizing appears on the sidewall or the tire profile looks different against the car's long, low body. That is why many owners decide on construction only after thinking through both road use and the restoration goal, not just the tire size alone.

Modifications can absolutely affect tire fitment on a 1958 Buick 70 Roadmaster, even when the tire size remains 800-15 or a close radial equivalent. Aftermarket wheels, changes in wheel width, altered offset, suspension work, or ride-height changes can all influence how the tire sits and clears the body.

That is why the wheel on the car should be measured rather than assumed, especially on an older vehicle that may have changed hands several times. A careful check of steering clearance, fender space, and suspension travel helps prevent choosing a tire that looks appropriate on paper but creates problems once installed.

Before driving a 1958 Buick 70 Roadmaster on new tires, inspect the wheels for correct diameter and sound condition, confirm that lug hardware is proper, and make sure the tires are inflated appropriately for their use. It also helps to look over suspension, steering, and brake components on a collector car before adding road miles.

A short, careful drive is the best first test after installation. Listen for rubbing during turns, watch for any pull or vibration, and recheck pressure once the tires have settled in. On a large car like a Roadmaster, even a correct-size tire should still be evaluated on the actual vehicle before moving into regular driving.

800-15 tires on a collector 1958 Buick 70 Roadmaster should be kept at the proper pressure for the specific tire and inspected regularly for cracking, bulges, cuts, tread wear, and slow air loss. Cars that spend long periods parked need extra attention because age and storage conditions can affect tire condition even with limited mileage.

A clean, dry storage space away from prolonged sunlight, high heat, and ozone sources helps preserve both the tire structure and the whitewall appearance. Regular movement of the car, periodic pressure checks, and a close look at sidewalls before each drive are sensible habits for any Roadmaster that is used seasonally or only on special occasions.