The 1956 Borgward Isabella came from a brief but distinctive chapter in postwar European motoring, blending compact dimensions with a more upscale feel than many small sedans of its day. That character matters when choosing tires, because this Isabella uses 13-inch fitments that split between traditional bias-ply sizes and Euro-metric radial alternatives depending on sub-model. Base and TS models use 590-13 or 165R13, while the SW uses 640-13 or 175R13. Available choices range from wide whitewall bias-ply styling to blackwall radial touring patterns. The right selection depends on whether the goal is restoration-minded appearance, period-style driving feel, or more modern road manners.
Which Tire Size Is Right for The 1956 Borgward Isabella
The 1956 Borgward Isabella uses four primary tire sizes, and the correct one depends on the exact sub-model rather than wheel diameter, since all of them fit 13-inch rims. The first step is identifying whether the car is a Base, SW, or TS, then deciding whether the goal is to stay with the original-style bias-ply fitment or use the radial size associated with that version.
165R13 is a Euro-metric radial size: 165 is the nominal section width in millimeters, R indicates radial construction, and 13 is the rim diameter in inches. On the 1956 Borgward Isabella, it serves as the radial fitment for Base and TS models and gives a distinctly European sizing format compared with the older numeric bias-ply alternative. Available options include blackwall radial tires from Michelin and Dunlop in series such as XAS-FF, XAS, and SP Sport Aquajet. It is the right size to evaluate when the car is already set up for radial use or when a more road-oriented radial presentation is the goal.
590-13 is a numeric bias-ply size in which the 5.90 figure represents the tire's nominal section width in inches and 13 identifies the rim diameter. For the 1956 Borgward Isabella, this is the bias-ply fitment paired with Base and TS models and delivers the traditional construction and appearance many restoration-minded owners want. The available product in this size is a BFGoodrich Silvertown Classic Bias Ply with a 2.375-inch wide whitewall. This size is the one to focus on when preserving a period-style stance matters more than moving to a radial alternative.
175R13 is a Euro-metric radial size, with 175 indicating nominal section width in millimeters, R denoting radial construction, and 13 matching the wheel diameter in inches. On the 1956 Borgward Isabella, this radial size belongs to the SW sub-model rather than the Base or TS. Product variety is narrower here than in 165R13, so the decision is less about sidewall treatment and more about confirming that the wagon uses this larger radial fitment. It is the size to consider when the SW is being kept on its radial setup and the wheel configuration matches that sub-model's requirements.
640-13 is a numeric bias-ply size, meaning the 6.40 figure reflects nominal section width in inches while the 13 refers to rim diameter. For the 1956 Borgward Isabella, this size is associated with the SW sub-model and represents the traditional bias-ply alternative to 175R13 radial sizing. The available choice is a BFGoodrich Silvertown Classic Bias Ply with a 2.25-inch wide whitewall, giving it a distinctly vintage presentation. This is the size to evaluate when an SW owner wants a more traditional look and construction while still staying within the sub-model's proper 13-inch fitment family.
Sub-model fitment matters on the 1956 Borgward Isabella because the Base and TS share one tire-size pairing, while the SW uses a different one. Identifying the exact sub-model keeps the search focused on the correct radial or bias-ply size family before comparing brands, sidewalls, or construction choices.
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1956 Borgward Isabella Base
The 1956 Borgward Isabella Base uses the same tire-size pattern as the TS, with a choice between a 590-13 bias-ply fitment and a 165R13 radial fitment. That makes the decision more about construction, appearance, and wheel setup than about sorting through several unrelated sizes.
The 1956 Borgward Isabella SW uses the larger pairing within this model line, with 640-13 in bias-ply form and 175R13 in radial form. Tire selection starts by staying within those SW-specific sizes, then deciding whether traditional bias-ply presentation or radial use better suits the car.
The 1956 Borgward Isabella TS shares its tire-fitment pattern with the Base, using either 590-13 bias-ply or 165R13 radial sizing. That gives TS owners a straightforward path: keep a traditional period-style bias-ply look or evaluate the radial option already associated with this sub-model.
Bias-Ply to Radial Tire Conversion for the 1956 Borgward Isabella
For 590-13 and 640-13 bias-ply fitments, several radial-equivalent options are available. For 590-13, the 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 equivalents 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 width and vehicle clearance should be checked before changing sizes or 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 1956 Borgward Isabella Tires for Sale
Available 1956 Borgward Isabella tires span BFGoodrich bias-ply wide whitewalls and blackwall radial choices from Michelin and Dunlop. The main comparison points are size family, construction, tire series, sidewall style, and the rim-width ranges that separate the narrow bias-ply fitments from the radial options.
These 1956 Borgward Isabella tire FAQs focus on sub-model sizing, 13-inch rim fitment, bias-ply versus radial choices, radial equivalents, appearance decisions, and the checks worth making before road use on a restored or regularly driven car.
Tire Size & Fitment
What tire size fits a 1956 Borgward Isabella?
The 1956 Borgward Isabella does not use one universal tire size across every sub-model. Base and TS models use either 590-13 in bias-ply form or 165R13 in radial form, while the SW uses either 640-13 in bias-ply form or 175R13 in radial form.
That means the first step is identifying whether the car is a Base, TS, or SW before choosing a tire. Once the sub-model is confirmed, the next decision is whether to keep the traditional bias-ply size and appearance or move within the radial size family associated with that version of the Isabella.
What size rim does a 1956 Borgward Isabella use?
The 1956 Borgward Isabella uses 13-inch rims across its covered tire fitments. That applies to the radial sizes 165R13 and 175R13 as well as the bias-ply sizes 590-13 and 640-13, so the wheel diameter remains consistent even though the tire sizes vary by sub-model.
Rim diameter is only part of the fitment picture, especially on a vintage European car. Wheel width still matters, because the available bias-ply and radial options do not share the same width ranges, and any aftermarket wheel change should be measured before selecting a tire strictly by its 13-inch diameter.
Do all 1956 Borgward Isabella sub-models use the same tire size?
No. The 1956 Borgward Isabella Base and TS share the same fitment pattern, using 590-13 bias-ply or 165R13 radial sizing, while the SW uses a different pair: 640-13 bias-ply or 175R13 radial sizing. All of them mount on 13-inch rims, but the tire sizes themselves are not the same.
That difference is important because a wagon-sized SW tire should not be treated as interchangeable with the Base or TS sizes simply because the wheel diameter matches. Sub-model confirmation helps narrow the right size family first, then the buyer can compare construction, appearance, and wheel-width compatibility within that correct range.
Bias-Ply & Radial Options
Is 590-13 a bias-ply or radial tire for the 1956 Borgward Isabella?
590-13 is a bias-ply tire size for the 1956 Borgward Isabella, and it applies to the Base and TS sub-models. The radial counterpart associated with that same fitment family is 165R13, which uses a Euro-metric radial sizing format rather than the older numeric bias-ply convention.
Choosing between them changes more than the lettering on the sidewall. A 590-13 selection keeps the traditional bias-ply construction and vintage presentation, while a 165R13 choice follows the radial path used on the same sub-models. Wheel width, tire clearance, and the car's intended use should all be confirmed before switching construction.
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, the equivalents are 175R13, P175/75R13, P185/70R13, and 650R13, with 650R13 serving as the bias-look radial option within that larger fitment family.
Those alternatives span several sizing conventions, from Euro-metric 80-series radials to 75-series and 70-series P-metric options. They should be treated as comparison choices rather than automatic substitutes, so it is wise to confirm wheel width, overall fit within the wheel opening, and how the car is currently set up before making the change.
What should I check before converting my 1956 Borgward Isabella from bias-ply to radial tires?
Start with the exact sub-model and original size family, because the Base and TS use 590-13 or 165R13 while the SW uses 640-13 or 175R13. From there, verify the wheel's 13-inch diameter and actual width, since the equivalent radial choices are tied to specific rim-width ranges.
A conversion also deserves a close look at fender and steering clearance, especially if the car has non-original wheels, altered ride height, or suspension wear. Radial equivalents can be considered for these cars, but the final decision should account for wheel compatibility, the car's current setup, and whether the owner values road manners or period-style appearance more.
Choosing the Right Tire
What should I consider when choosing a tire for a 1956 Borgward Isabella?
The most important factor is matching the tire to the exact sub-model. Base and TS models use the 590-13 and 165R13 fitment family, while the SW uses 640-13 and 175R13. After that, the main decision is whether to stay with traditional bias-ply construction or choose the radial size associated with that version.
Once the correct size family is established, compare the tire's intended look and wheel requirements. Wide whitewall bias-ply options suit a more restoration-oriented presentation, while blackwall radials create a different visual character. Rim width, load capacity, and how the car is driven should all guide the final choice within the proper size.
What sidewall styles are available for 1956 Borgward Isabella tires?
Sidewall choices for the 1956 Borgward Isabella include blackwall and wide whitewall styles. The radial options in 165R13 are blackwall tires, while the available bias-ply tires in 590-13 and 640-13 use wide whitewall sidewalls that create a much more traditional mid-century appearance.
That sidewall difference can shape the whole look of the car even when the wheel diameter stays the same. A blackwall radial tends to suit a more road-use-focused presentation, while a wide whitewall bias-ply gives the Isabella a distinctly period-style visual signature. The right choice depends on whether appearance or construction is the stronger priority.
What brands offer tires for the 1956 Borgward Isabella?
Michelin, Dunlop, and BFGoodrich all offer tires within the 1956 Borgward Isabella fitment range. Michelin and Dunlop appear in the 165R13 radial size, while BFGoodrich covers the bias-ply side with 590-13 and 640-13 offerings in the Silvertown Classic Bias Ply line.
Brand choice should still come after the size and construction are settled. Once the car's sub-model and tire family are confirmed, the buyer can compare differences in sidewall presentation, tire series, load figures where given, and wheel-width suitability. That approach keeps the selection grounded in fitment rather than choosing by brand name alone.
Restoration & Appearance
Which tire should I choose for a period-style 1956 Borgward Isabella?
A period-style 1956 Borgward Isabella usually starts with the bias-ply size associated with the exact sub-model. That means 590-13 for Base and TS models or 640-13 for the SW, both offered here in BFGoodrich Silvertown Classic Bias Ply form with wide whitewall styling.
That choice supports a more traditional stance and visual character than a modern-style radial blackwall. For buyers focused on exact originality, tire size is only one part of the picture, so marque references or period photographs can help refine the final sidewall and presentation decision before the car goes back on the road.
How does tire construction affect the appearance of a restored 1956 Borgward Isabella?
Tire construction changes the restored car's visual character as much as its road feel. On a 1956 Borgward Isabella, the bias-ply choices are numeric sizes with wide whitewall styling, while the radial choices use Euro-metric sizing and blackwall sidewalls, giving the car a more modernized presentation.
That difference is easy to see even at a glance, so construction should be chosen with the restoration goal in mind. A buyer preserving a traditional mid-1950s look may lean toward the bias-ply fitment, while someone prioritizing drivability may prefer the radial path, provided the wheel setup matches the selected size.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1956 Borgward Isabella?
Yes. A 1956 Borgward Isabella can be affected by aftermarket wheels, changed wheel widths, suspension alterations, ride-height changes, or bodywork that shifts available clearance. Even though the covered sizes all use 13-inch rims, those changes can still influence whether the selected bias-ply or radial tire suits the car's current setup.
That is especially important when moving between the narrower 590-13 family and the larger 640-13 family or when evaluating radial equivalents. Measuring the actual wheel width and checking steering, fender, and suspension clearance helps avoid choosing a tire simply because it sounds close to the original size on paper.
What should I inspect before driving a 1956 Borgward Isabella on new tires?
Inspect the wheels for the correct 13-inch diameter and appropriate width for the tire being installed, then check the valve stems, wheel condition, and overall mounting quality. It also makes sense to look at suspension and steering components, because looseness or wear can affect how a vintage car behaves on fresh tires.
After installation, confirm proper inflation, watch for any air loss, and turn the steering from lock to lock to check clearance. A short shakedown drive can reveal rubbing, vibration, or pull that deserves attention before regular use. On an older collector car, those checks are just as important as selecting the right size.
How should tires on a collector 1956 Borgward Isabella be maintained?
Collector-car tires should be inspected regularly even when the car is driven only occasionally. On a 1956 Borgward Isabella, that means checking pressure, tread condition, sidewall cracking, cuts, bulges, and any signs of slow air loss, whether the car wears bias-ply whitewalls or blackwall radial tires.
Storage conditions matter almost as much as mileage on a lightly used vintage car. Keeping the Isabella away from prolonged sunlight, excess heat, moisture, and ozone sources helps protect the rubber, and periodic inspection remains wise because age-related deterioration can appear long before the tread looks worn out.
