1956 Opel Kapitan Tires

The 1956 Opel Kapitan uses two tire sizes: 640-13 in bias-ply construction and 175R13 in radial construction. Both sizes are tied to a 13-inch wheel, so the car can be approached either as a traditional bias-ply fitment or as a radial-equipped setup, depending on the tire style and driving character being pursued.

That means the first step is deciding whether the Kapitan is staying closer to its period-style tire construction or moving to a radial format. Once that choice is made, it is still smart to confirm actual wheel width and inspect the car for any prior wheel, suspension, or body changes that could affect clearance.

The 1956 Opel Kapitan uses a 13-inch rim diameter with both of its applicable tire sizes, 640-13 and 175R13. Even though the two tires use different sizing systems and different construction types, they are both built around the same 13-inch wheel diameter.

Rim diameter is only one part of the fitment picture on a collector car. A radial-equivalent path can call for checking wheel width more closely, and any car that has been altered over the years may no longer have its original wheel setup, so a hands-on wheel measurement is worth doing before selecting tires.

The 1956 Opel Kapitan Base uses the same fitment pattern as the overall model coverage, with 640-13 bias-ply and 175R13 radial sizes both applying to it. There is no separate Base-only tire size that changes the basic 13-inch fitment decision on this page.

That makes the Base model relatively straightforward to shop for, since the real choice is construction and appearance rather than a trim-specific size difference. A buyer can focus on whether the car should wear a traditional bias-ply look or a radial format, then verify wheel width and clearance before making the final call.

640-13 is a bias-ply tire size for the 1956 Opel Kapitan. It uses the older numeric bias-ply sizing system and represents the traditional tire format associated with the car's mid-1950s appearance, profile, and overall presentation on a 13-inch wheel.

Choosing 640-13 usually means prioritizing a period-style look and staying closer to the car's original tire character. Owners considering a move away from bias-ply should compare the radial alternatives carefully, since construction changes can affect the tire's visual profile and call for closer attention to wheel width and clearance.

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 equivalent. Each one offers a different sizing convention while staying in the same general replacement conversation for a 13-inch Kapitan tire.

Those choices are not all the same in profile or appearance, so the decision should match the car's use and visual goals. A 4-6 inch rim-width range is associated with these radial equivalents, and the wheel setup, overall dimensions, and available clearance should be checked before changing away from 640-13 bias-ply tires.

A conversion from 640-13 bias-ply to a radial choice such as 175R13, P175/75R13, P185/70R13, or 650R13 starts with wheel compatibility. The Kapitan stays on a 13-inch rim, but radial-equivalent choices also bring wheel-width considerations, and the associated rim-width range for those equivalents is 4-6 inches.

It also helps to inspect the actual car rather than assuming it still matches its original setup. Steering clearance, suspension condition, fender space, and any past wheel changes should be reviewed before making the switch, especially on an older vehicle that may have seen repairs or modifications over many decades.

Start by deciding whether the Kapitan should keep its traditional bias-ply character. In 640-13, the main available choice shown here is a BFGoodrich Silvertown Classic Bias Ply with a 2.25 inch wide whitewall, so the selection centers on maintaining the vintage size, construction, and sidewall presentation.

That makes 640-13 especially relevant for restoration-minded owners who want the car to look at home in its mid-1950s setting. Beyond appearance, wheel width still matters, and the condition of the car's suspension, steering components, and existing wheels should be checked before putting an older sedan back into regular road use.

The sidewall style currently represented for the 1956 Opel Kapitan is a wide whitewall in the 640-13 bias-ply size. On a car from this era, that kind of sidewall treatment has a strong effect on the overall look, often shaping the visual balance of the wheel opening more than the tread design itself.

A wide whitewall suits buyers aiming for a distinctly period-style presentation, especially on a restoration-oriented sedan. Even so, appearance should be balanced against the construction choice, because a radial-format tire and a bias-ply wide-whitewall tire can give the car a noticeably different stance and visual character.

BFGoodrich is represented among the available 1956 Opel Kapitan tire options shown here, specifically in the 640-13 bias-ply size. That product belongs to the Silvertown Classic Bias Ply line and combines the traditional numeric size with a 2.25 inch wide whitewall presentation.

Brand choice on a vehicle like the Kapitan matters less as a ranking exercise and more as part of the tire's overall character. The more useful comparison is whether the available product supports the desired construction, sidewall appearance, and wheel fitment, especially when the goal is to preserve a coherent mid-century look.

For a period-style 1956 Opel Kapitan, the 640-13 bias-ply tire is the most natural starting point because it preserves the vintage numeric sizing format and traditional construction. The available BFGoodrich Silvertown Classic Bias Ply with a 2.25 inch wide whitewall also aligns well with the type of visual treatment many buyers want on a mid-1950s sedan.

That does not automatically make it the right answer for every restoration, since exact originality questions can depend on the car's market, trim, and historical documentation. Buyers chasing a very specific restoration standard should compare the tire choice against marque references, period photos, and other authoritative vehicle-specific records.

Tire construction changes the look of a restored 1956 Opel Kapitan more than many owners expect. A 640-13 bias-ply tire preserves the older sizing language and traditional visual character, while a 175R13 or other radial-format equivalent introduces a more modern tire convention even though the car remains on a 13-inch rim.

That visual difference matters because the Kapitan's body lines and wheel openings are part of a distinctly mid-1950s design. Buyers restoring for shows, events, or a period-style street presence often weigh sidewall treatment and construction together, rather than treating the tire as a purely mechanical replacement item.

Yes, modifications can affect tire fitment on a 1956 Opel Kapitan even when the nominal tire size stays within the usual 13-inch range. Aftermarket wheels, changes in wheel width, suspension work, lowering, repaired body panels, or altered steering components can all change how a 640-13 or 175R13 tire sits in the car.

That is why an older vehicle should be measured as it exists today rather than judged only by catalog fitment. A close check of wheel width, inner and outer clearance, and steering travel is worthwhile before choosing either a traditional bias-ply tire or one of the radial alternatives tied to 640-13.

Before driving a 1956 Opel Kapitan on new tires, inspect the wheels for correct diameter and condition, confirm proper mounting, and look over the suspension and steering for worn parts that could affect how the car tracks. It also helps to verify that the tire choice matches the intended wheel width and the car's present-day setup.

Road readiness on a collector car goes beyond the new tires themselves. Tire pressure, visible clearance at the fenders and suspension, and the condition of wheel hardware all deserve attention, especially after the first few miles, when any rubbing, vibration, or air loss will usually show up quickly.

640-13 tires on a collector 1956 Opel Kapitan should be maintained with regular pressure checks, visual inspections, and attention to aging as much as tread wear. On a lightly used vintage sedan, sidewall cracking, flat spotting from storage, cuts, bulges, and slow air loss can matter more than mileage alone.

Storage conditions also play a big part in how long collector-car tires stay usable. Keeping the car away from prolonged sunlight, heat, moisture, and ozone sources helps preserve the rubber, and any tire that shows significant age-related deterioration should be evaluated before the Kapitan is returned to normal road driving.