1955 Opel Kapitan Tires

The 1955 Opel Kapitan uses two recognized tire sizes: 640-13 in bias-ply construction and 175R13 in radial construction. Both sizes are tied to 13-inch rims, so the choice is less about wheel diameter and more about which construction style suits the car and the owner’s goals.

A buyer choosing between these sizes should start by confirming the actual wheels currently on the car, especially if it has been restored or modified over the years. Once the rim diameter and width are verified, the decision becomes whether to keep the traditional bias-ply format or use the radial-style size that matches the same basic wheel diameter.

The 1955 Opel Kapitan uses a 13-inch rim with both of its recognized tire sizes, 640-13 and 175R13. That shared rim diameter simplifies fitment compared with vehicles that changed wheel diameter between trims or tire constructions.

Rim diameter is only one part of the fitment picture, so the wheel’s actual width still deserves attention before selecting a tire. That matters most when comparing the original-style bias-ply size with a radial alternative, since tire construction and section shape can change how the tire sits on the wheel and clears the car.

640-13 is a numeric bias-ply tire size. The 640 portion refers to an approximate 6.40-inch nominal section width, and the 13 indicates the wheel diameter in inches, making it a traditional vintage sizing format rather than a modern metric radial one.

For a 1955 Opel Kapitan, that size points toward the car’s period-style tire presentation and the feel associated with bias-ply construction. It is also the size from which the common radial equivalents are derived, so owners considering a construction change can use 640-13 as the baseline when comparing wheel compatibility, clearance, and appearance.

640-13 is the bias-ply tire size for the 1955 Opel Kapitan. It uses a vintage numeric sizing format and represents the traditional construction choice for owners who want the car to retain an earlier tire profile and period-style presentation.

That matters because a bias-ply tire is not the same thing as a radial equivalent, even when both are intended for the same 13-inch wheel diameter. Owners comparing the two should look beyond the size code and confirm wheel width, overall fit on the car, and whether the goal is restoration character or a different road-use setup.

Radial equivalents for 640-13 include 175R13 as the 80-series metric radial, P175/75R13 as the 75-series P-metric radial, P185/70R13 as the 70-series P-metric radial, and 650R13 as a bias-look radial. These choices give the 1955 Opel Kapitan several ways to move from a bias-ply baseline to a radial-format alternative.

Each equivalent should be treated as a comparison point rather than an automatic replacement. Rim width, wheel design, tire clearance, and the car’s intended use all deserve a close look, especially because the available equivalents span different sizing systems and include both conventional radial styling and a more vintage-looking bias-look radial option.

Start by confirming the actual 13-inch wheels on the car and checking their width against the radial size being considered. The 640-13 equivalent radial options are associated with a 4-6 inch rim-width range, so wheel width is an important first checkpoint before choosing 175R13, P175/75R13, P185/70R13, or 650R13.

Clearance at the fenders, steering, and suspension should be inspected next, especially on a car that may have seen wheel or ride-height changes over the years. It also helps to decide whether the Kapitan is being kept close to its original character or prepared for more regular road driving, since that often shapes whether bias-ply or radial construction makes more sense.

Choosing a 640-13 tire starts with staying in the correct vintage bias-ply size for the car’s 13-inch wheel. From there, the main selection points are whether the tire’s construction suits a restoration-oriented goal and whether the available sidewall treatment matches the look the owner wants for the Kapitan.

The available 640-13 product choice includes BFGoodrich in the Silvertown Classic Bias Ply series with a wide whitewall presentation. Rim-width compatibility also matters, so it is worth measuring the wheel before purchase and comparing the tire not only by appearance, but also by how well it aligns with the car’s current wheel setup and intended use.

The available 640-13 product selection for the 1955 Opel Kapitan includes a wide whitewall sidewall style. That sidewall treatment gives the car a distinctly mid-century visual character and is often the first appearance choice buyers notice when selecting a period-style tire.

Sidewall style should be chosen with the broader look of the car in mind rather than treated as a purely cosmetic afterthought. Owners focused on a traditional presentation may prefer the wide whitewall approach, while anyone comparing against a radial conversion should remember that construction and sizing format can influence appearance even when the wheel diameter stays the same.

BFGoodrich is available in the 640-13 fitment for the 1955 Opel Kapitan. That product appears in the Silvertown Classic Bias Ply series and focuses on the traditional bias-ply side of this vehicle’s fitment rather than the radial-equivalent path.

Brand choice is only one part of the decision, so it helps to compare the tire by size, construction, sidewall style, and wheel compatibility at the same time. On a car like the Kapitan, a buyer usually gets the best result by starting with the intended look and driving use, then confirming that the tire format still matches the vehicle’s actual wheel setup.

A period-style 1955 Opel Kapitan usually starts with the 640-13 bias-ply size, since it preserves the vintage numeric format and traditional construction associated with the car’s era. That makes it the natural fitment direction for owners who want the tire to support an authentically older visual impression.

The available BFGoodrich Silvertown Classic Bias Ply with a wide whitewall reinforces that traditional look, but exact restoration goals can vary from car to car. When originality matters at a detailed level, it is smart to compare the tire choice with marque-specific references, period photos, and restoration documentation instead of assuming every correct-size vintage tire reflects the same historical appearance.

Tire construction changes more than road feel on a restored 1955 Opel Kapitan; it also changes how the car presents visually. A 640-13 bias-ply keeps the older numeric sizing format and more traditional look, while a radial such as 175R13 introduces a newer sizing convention and a different overall tire presentation.

That visual difference becomes more noticeable on a car from the mid-1950s, where sidewall profile and period styling work together. A buyer restoring the Kapitan should think about construction, sidewall treatment, and wheel stance as one package, especially if the goal is to preserve the car’s original-era character rather than simply match the rim diameter.

Yes, modifications can affect tire fitment on a 1955 Opel Kapitan even when the tire size appears correct on paper. Aftermarket wheels, changes in wheel width, altered ride height, brake updates, or body repairs can all influence how a 640-13 or 175R13 tire sits and clears the car.

That is why the actual vehicle should be checked before settling on either the bias-ply or radial format. A tire that matches the intended size still needs proper clearance during steering and suspension movement, and a car that has been modified over time may need more careful wheel and fitment verification than an untouched example.

Before driving a 1955 Opel Kapitan on new tires, inspect the wheels for damage, confirm the wheel diameter and width, and make sure the tires are seated properly and inflated correctly. A quick check of valve stems, lug hardware, and visible clearance around the fenders and suspension is also worthwhile.

Collector cars often sit for long periods, so the inspection should extend beyond the tires alone. Steering play, worn suspension parts, brake condition, and uneven ride height can all affect how the car behaves on fresh rubber, especially when changing from an old, aged tire to a new bias-ply or radial-format fitment.

640-13 tires on a collector 1955 Opel Kapitan should be maintained with regular pressure checks, routine visual inspection, and careful storage habits. Look for sidewall cracking, cuts, bulges, irregular tread wear, or slow air loss, since vintage-use vehicles often age tires by time and storage conditions rather than by mileage alone.

Keeping the car away from prolonged sunlight, excess heat, moisture, and ozone sources can help preserve tire condition between drives. It also helps to inspect the tires before each outing instead of assuming they are road-ready because the tread still looks good, especially on a collector vehicle that may spend long stretches parked.