The 1955 Borgward Isabella came from a period when European sedans were balancing compact dimensions, modern styling, and increasingly refined road manners. That makes tire choice especially important, because the Isabella sits at the transition between traditional bias-ply fitment and early radial thinking. Depending on sub-model, this car uses either 590-13 or 640-13 bias-ply sizing, with 165R13 and 175R13 radial fitments on the same 13-inch rim diameter. Available choices range from Michelin and Dunlop radial designs to BFGoodrich wide whitewall bias-ply options. The right decision comes down to confirming the exact Isabella variant, then matching appearance, construction, and wheel setup to the way the car is being restored or driven.
Which Tire Size Is Right for The 1955 Borgward Isabella
The 1955 Borgward Isabella uses four primary tire sizes, and the correct one depends first on the exact sub-model. Base and TS models use 165R13 radial or 590-13 bias-ply sizing, while the SW uses 175R13 radial or 640-13 bias-ply sizing, all on 13-inch wheels. Before choosing a tire, confirm which Isabella version you have and whether you want to keep its original-style construction or evaluate a radial alternative.
165R13 is a Euro-metric radial size in which 165 refers to nominal section width in millimeters, R identifies radial construction, and 13 is the wheel diameter in inches. On the 1955 Borgward Isabella, this size serves Base and TS applications where a radial fitment is used on a 13-inch rim. Available choices include Michelin XAS-FF, Michelin XAS, and Dunlop SP Sport Aquajet, all in blackwall form. This size makes sense for owners who want an authentic European radial presentation while still checking wheel width and overall vehicle setup before installation.
590-13 is a numeric bias-ply size, with the 590 indicating a nominal section width of about 5.90 inches and the 13 identifying the rim diameter. On the 1955 Borgward Isabella, it is the bias-ply fitment used with Base and TS applications and preserves a distinctly traditional tire profile. The available product in this size is a BFGoodrich Silvertown Classic Bias Ply with a wide whitewall treatment. It is the natural size to consider when the goal is a restoration-oriented look, original-style construction, and compatibility with narrower period wheel widths.
175R13 is a Euro-metric radial size, meaning a nominal 175-millimeter section width, radial construction, and a 13-inch rim diameter. On the 1955 Borgward Isabella, this size is used for the SW and represents the radial-side fitment for that specific variant. Even without multiple product lines shown here, the sizing itself matters because it differs from the Base and TS setup and should not be assumed interchangeable. This is the size to evaluate when confirming SW fitment and comparing radial road-use needs against wheel width, clearance, and overall stance.
640-13 is a numeric bias-ply size, where 640 represents an approximate 6.40-inch nominal section width and 13 matches the wheel diameter. On the 1955 Borgward Isabella, it is the bias-ply size associated with the SW, giving that sub-model a different primary fitment than the Base and TS. The available choice is a BFGoodrich Silvertown Classic Bias Ply with a wide whitewall sidewall style. This size is worth choosing when the car is an SW and the goal is to retain a period-style bias-ply appearance while staying mindful of wheel width and body clearance.
Sub-model fitment matters on the 1955 Borgward Isabella because the Base and TS share one tire-sizing pattern, while the SW uses a larger set of sizes. Identifying the exact Isabella variant is the first step before comparing bias-ply and radial choices on the common 13-inch rim diameter.
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1955 Borgward Isabella Base
The 1955 Borgward Isabella Base uses the same tire-sizing pattern as the TS, with a choice between a radial fitment and a bias-ply fitment on 13-inch wheels. That makes the decision less about sub-model differences and more about whether the car is being kept in a traditional visual style or set up for radial road use.
The 1955 Borgward Isabella SW uses its own larger tire-sizing combination, distinct from the Base and TS, even though it stays on a 13-inch rim diameter. Tire selection for the SW starts with confirming that specific body designation, then choosing between a period-style bias-ply look or one of the available radial equivalents.
The 1955 Borgward Isabella TS shares its tire-sizing pattern with the Base, using the same radial and bias-ply sizing choices on 13-inch wheels. That keeps fitment straightforward once the TS is confirmed, and the main decision becomes construction, appearance, and compatibility with the wheels actually on the car.
Bias-Ply to Radial Tire Conversion for the 1955 Borgward Isabella
The 1955 Borgward Isabella has radial-equivalent options for both primary bias-ply sizes. For 590-13, the available equivalents are 165R13 as an 80-series metric radial, P165/75R13 as a 75-series P-metric radial, and P175/70R13 as a 70-series P-metric radial. For 640-13, the choices are 175R13 as an 80-series metric radial, P175/75R13 as a 75-series P-metric radial, P185/70R13 as a 70-series P-metric radial, and 650R13 as a bias-look radial. Recommended rim-width ranges are 4-5 inches for 590-13 and 4-6 inches for 640-13, so wheel size, tire dimensions, and clearance should all be checked before changing construction.
Modern Radial Equivalents
165R13
Equivalent 80-series Metric Radial (590-13)
P165/75R13
Equivalent P-metric 75-series Radial (590-13)
P175/70R13
Equivalent P-metric 70-series Radial (590-13)
175R13
Equivalent 80-series Metric Radial (640-13)
P175/75R13
Equivalent P-metric 75-series Radial (640-13)
P185/70R13
Equivalent P-metric 70-series Radial (640-13)
650R13
Bias-look Radial Equivalent (640-13)
Important Considerations When Replacing Bias Ply With Radial
Compare overall diameter and section width carefully to ensure proper fit.
Verify recommended rim range (4-6 in) and load needs match your vehicle specifications.
Check fender clearance, steering clearance, and stance before installation.
Consider suspension condition and intended road use when choosing equivalents.
Important Fitment Notes
The tire sizes listed on this page assume factory-standard vehicle configuration. The following modifications may affect tire fitment and are not reflected in this guide:
Suspension changes (lowering, lift kits, spring replacements)
Body alterations (fender modifications, custom bodywork)
If your vehicle has been modified from factory specifications, verify tire clearance before purchase.
Best 1955 Borgward Isabella Tires for Sale
Available 1955 Borgward Isabella tires span Michelin, Dunlop, and BFGoodrich choices across radial and bias-ply construction. The product grid lets you compare blackwall European-style radials against wide whitewall Silvertown Classic Bias Ply options in the correct 13-inch fitments.
These 1955 Borgward Isabella tire FAQs focus on sub-model size differences, 13-inch rim fitment, bias-ply versus radial choices, available equivalents, and the practical checks that matter before putting a restored or regularly driven Isabella on the road.
Tire Size & Fitment
What tire size fits a 1955 Borgward Isabella?
A 1955 Borgward Isabella can use 165R13, 590-13, 175R13, or 640-13, depending on the exact sub-model and whether the car is set up with radial or bias-ply tires. Base and TS applications use 165R13 radial or 590-13 bias-ply sizing, while the SW uses 175R13 radial or 640-13 bias-ply sizing.
The first step is identifying whether the car is a Base, SW, or TS, because the radial and bias-ply pairings are not the same across all Isabella versions. Once that is confirmed, compare the wheel width, the construction you want to run, and the appearance goal before choosing among the available tire options.
What size rim does a 1955 Borgward Isabella use?
The 1955 Borgward Isabella uses a 13-inch rim diameter across all of its listed tire sizes. That includes both the radial sizes, 165R13 and 175R13, and the bias-ply sizes, 590-13 and 640-13.
Rim diameter is only part of the fitment picture, so it is still important to confirm the actual wheel width before mounting a tire. Many collector cars have had wheels changed over the years, and that can affect whether a radial or bias-ply choice suits the car's current setup and intended use.
Do all 1955 Borgward Isabella sub-models use the same tire size?
No, all 1955 Borgward Isabella sub-models do not use the same tire size. The Base and TS share 165R13 radial and 590-13 bias-ply sizing, while the SW uses the larger 175R13 radial and 640-13 bias-ply combination.
That difference matters because choosing by year, make, and model alone can lead to the wrong tire if the sub-model is not confirmed. The common 13-inch rim diameter can make the cars seem similar at a glance, but the tire width and construction choices should still match the specific Isabella variant.
Bias-Ply & Radial Options
Is 590-13 a bias-ply or radial tire for the 1955 Borgward Isabella?
590-13 is a bias-ply tire size for the 1955 Borgward Isabella. It is used on Base and TS applications as the traditional numeric bias-ply fitment, while 165R13 serves as the corresponding radial fitment for those same sub-models.
That distinction matters because a bias-ply tire affects both the appearance and the overall setup of the car differently than a radial. Anyone considering a change to radial construction should confirm wheel width, compare the equivalent radial sizes carefully, and make sure the car has enough clearance for the chosen alternative.
What radial tire sizes are equivalent to 590-13 and 640-13?
For 590-13, radial equivalents include 165R13, P165/75R13, and P175/70R13. For 640-13, radial equivalents include 175R13, P175/75R13, P185/70R13, and 650R13 as a bias-look radial option.
These equivalents give Isabella owners several ways to move from a numeric bias-ply size into radial sizing, but they should be treated as alternatives rather than automatic substitutes. Wheel-width guidance, overall tire dimensions, and vehicle clearance still need to be checked so the chosen radial works with the car's wheels and body setup.
What should I check before converting my 1955 Borgward Isabella from bias-ply to radial tires?
Start by confirming the sub-model and the original bias-ply size, since the Base and TS use a different pair of sizes than the SW. Then compare the intended radial equivalent against the car's 13-inch wheels, paying attention to the recommended rim-width range where it is available.
Construction changes can also affect how the Isabella sits and drives, so clearance at the fenders, steering components, and suspension should be reviewed before mounting the new tires. A car with replacement wheels, altered ride height, or older suspension parts deserves an especially careful fitment check before making the switch.
Choosing the Right Tire
What should I consider when choosing a tire for a 1955 Borgward Isabella?
The main factors are the exact sub-model, the correct tire size, and whether the car will stay with a bias-ply setup or move to a radial. Base and TS applications follow one sizing pattern, while the SW uses a different pair of sizes even though all versions share a 13-inch rim diameter.
After size and construction are settled, look at the car's intended use and visual goal. A wide whitewall bias-ply gives a stronger restoration-oriented presentation, while blackwall radial options suit owners focused on European-style road use, provided the wheel width and fitment details support the choice.
What sidewall styles are available for 1955 Borgward Isabella tires?
The available 1955 Borgward Isabella tire options include blackwall and wide whitewall sidewall styles. The radial 165R13 choices from Michelin and Dunlop are blackwall tires, while the 590-13 and 640-13 bias-ply offerings are wide whitewall BFGoodrich Silvertown Classic Bias Ply designs.
That gives the Isabella owner a clear visual decision as well as a fitment decision. Blackwalls usually support a cleaner European radial appearance, while wide whitewalls create a stronger period-style impression, so the right choice depends on whether the goal is visual authenticity, driving preference, or a blend of both.
What brands offer tires for the 1955 Borgward Isabella?
Tires for the 1955 Borgward Isabella are available from Michelin, Dunlop, and BFGoodrich. Michelin and Dunlop cover the 165R13 radial fitment, while BFGoodrich supplies the 590-13 and 640-13 bias-ply sizes in the Silvertown Classic Bias Ply series.
Brand choice should be considered alongside size, construction, and sidewall style rather than by name alone. Some Isabella owners will be comparing blackwall radial options within the 165R13 fitment, while others will be focused on the traditional wide whitewall look offered in the two numeric bias-ply sizes.
Restoration & Appearance
Which tire should I choose for a period-style 1955 Borgward Isabella?
For a period-style 1955 Borgward Isabella, the numeric bias-ply sizes are the natural starting point: 590-13 for Base and TS, and 640-13 for SW. Those sizes preserve the traditional bias-ply construction and are available with wide whitewall presentation in the Silvertown Classic Bias Ply line.
That choice is often as much about visual character as fitment. Owners aiming for exact restoration accuracy should still compare the tire's appearance against marque references, period photos, or other vehicle-specific documentation, since a period-style size and sidewall treatment is not automatically the same thing as proven factory delivery.
How does tire construction affect the appearance of a restored 1955 Borgward Isabella?
Tire construction changes the visual impression of a restored 1955 Borgward Isabella because bias-ply and radial tires present the car differently even when they fit the same rim diameter. The bias-ply sizes, 590-13 and 640-13, support a more traditional look, while 165R13 and 175R13 radials give the car a more modern tire profile.
Sidewall style shapes that impression even further. A wide whitewall bias-ply creates a distinctly vintage presentation, while a blackwall radial looks cleaner and more understated, so the better choice depends on whether the Isabella is being restored for show-oriented authenticity, regular road use, or a balanced collector-driver setup.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1955 Borgward Isabella?
Yes, modifications can affect tire fitment on a 1955 Borgward Isabella even when the tire size itself is correct for the sub-model. Changes such as aftermarket wheels, different wheel widths, suspension work, ride-height changes, or body repairs can alter how much room the tire has around the fenders and steering components.
That is especially important when moving between bias-ply and radial construction or when using one of the radial-equivalent sizes for a numeric bias-ply fitment. A careful check of wheel dimensions, turning clearance, and suspension condition helps prevent rubbing, uneven stance, or other fitment problems once the car is back on the road.
What should I inspect before driving a 1955 Borgward Isabella on new tires?
Before driving a 1955 Borgward Isabella on new tires, inspect the wheels, valve stems, and overall mounting condition, then confirm proper inflation and even seating on the rim. It is also wise to look over suspension and steering components, especially on a collector car that may have spent long periods parked.
A short initial road test should be followed by another visual check for clearance issues, air loss, or signs of contact at full steering lock. Any Isabella with older wheels, recent restoration work, or a conversion from bias-ply to radial deserves extra attention before being trusted on a longer drive.
How should tires on a collector 1955 Borgward Isabella be maintained?
Tires on a collector 1955 Borgward Isabella should be maintained with regular pressure checks, periodic visual inspection, and attention to aging even if the car is driven only occasionally. Sidewall cracking, bulges, tread separation, flat spotting, and slow air loss all matter on a lightly used collector vehicle.
Storage conditions are just as important as mileage. Keeping the Isabella away from prolonged sunlight, moisture, heat, and ozone sources helps protect both bias-ply and radial tires, and routine inspections before each drive help catch age-related problems early on a car that may spend much of its life parked.
