1958 Fiat 600 Tires

A 1958 Fiat 600 uses two primary tire sizes: 520-12 in bias-ply construction and 135R12 in radial construction. Both the Base and Multipla are associated with these same sizes, and both are built around a 12-inch rim diameter.

That means the first question is less about sub-model differences and more about which construction style suits the car. A 520-12 keeps the vintage numeric bias-ply format, while 135R12 uses a Euro-metric radial format. Before choosing either one, confirm the actual wheel diameter and make sure the car has not been changed to a different wheel setup over the years.

The 1958 Fiat 600 uses a 12-inch rim diameter with both of its associated tire sizes, 520-12 and 135R12. That shared rim diameter keeps the decision centered on tire construction and style rather than moving between different wheel diameters.

Even with the correct 12-inch diameter, wheel details still matter. A collector car may have replacement wheels, later wheels, or aftermarket wheels that change width or fitment. It is wise to measure the wheel already on the car before selecting a tire, especially when comparing a vintage bias-ply size to a radial alternative or radial-equivalent option.

Yes. The covered 1958 Fiat 600 sub-models share the same tire-size choices: 520-12 in bias-ply construction and 135R12 in radial construction. That applies to both the 600 Base and the 600 Multipla, so the fitment path is consistent across these versions.

Shared size options make the buying decision simpler, but the tire still needs to match the way the vehicle is being finished and driven. A bias-ply tire supports a more traditional visual presentation, while the radial size changes the sizing format and construction type. On any restored or modified car, confirm the wheels and available clearance before making the final choice.

520-12 is a bias-ply tire size on the 1958 Fiat 600. It uses the traditional numeric bias-ply sizing system, with the first number reflecting nominal section width and the final number showing the 12-inch rim diameter.

That matters because a bias-ply tire affects both appearance and tire selection. In this size, BFGoodrich offers blackwall and wide whitewall versions, giving the car a more vintage presentation. Owners comparing it with the 135R12 radial should keep in mind that the construction type changes along with the size format, so wheel width and overall fitment should still be verified.

Radial equivalents for 520-12 include 125R12 and P125/75R12. The 125R12 option is an 80-series metric radial equivalent, while P125/75R12 is a P-metric 75-series radial equivalent, giving two different radial sizing conventions tied to the original bias-ply size.

A recommended rim-width range of 4 to 5 inches applies when evaluating those radial equivalents. Even though they share the same general role as alternatives to 520-12, they should be treated as comparison options rather than automatic substitutions. Checking wheel width, overall dimensions, and clearance around the suspension and body is the safest way to evaluate the change.

Start by confirming the wheel diameter and width already on the car, then compare the intended radial size against the existing bias-ply setup. On a 1958 Fiat 600, the common path is moving from 520-12 bias-ply to a radial size such as 125R12, P125/75R12, or 135R12, depending on the setup being used.

The practical checks are wheel compatibility, tire clearance, and the condition of the suspension and steering components. A small collector car can be sensitive to changes in tire shape and construction, especially if the wheels have been replaced or the suspension has been altered. A careful measurement of wheel width and available space helps avoid surprises after installation.

The main considerations for a 520-12 tire are keeping the correct numeric bias-ply size, staying with the 12-inch rim diameter, and deciding what kind of vintage presentation suits the car. In this size, the available BFGoodrich choices include both blackwall and 2.00 inch wide whitewall versions within the Silvertown Classic Bias Ply series.

That makes appearance a major part of the decision, especially on a restoration-oriented Fiat 600. A blackwall keeps the look simple and restrained, while a wide whitewall creates a more decorative period-style finish. Wheel width should still be confirmed, and any buyer using the car regularly on the road may also want to compare the bias-ply choice against radial-format alternatives.

The available sidewall styles for 1958 Fiat 600 tires include blackwall and wide whitewall. Blackwall appears in both the 135R12 radial and 520-12 bias-ply offerings, while the wide whitewall treatment is available in the 520-12 BFGoodrich bias-ply line.

Sidewall style changes the visual character of the car more than many buyers expect, especially on a compact 1950s European model with small 12-inch wheels. A whitewall can push the car toward a more dressy, restoration-oriented look, while a blackwall keeps it more understated. Sidewall style should be chosen after the size and construction have already been confirmed.

Firestone and BFGoodrich both offer tires for the 1958 Fiat 600. Firestone covers the 135R12 radial option with the F560 Radial series, while BFGoodrich covers the 520-12 bias-ply option in the Silvertown Classic Bias Ply series.

That brand split also reflects the two different tire directions available for this Fiat. One path keeps the car in a traditional bias-ply format with sidewall style choices, and the other moves into a radial format on the same 12-inch rim diameter. The better comparison is not brand against brand, but size, construction, and appearance against the way the car will be used.

For a period-style 1958 Fiat 600, the 520-12 bias-ply size is the natural starting point because it preserves the vintage numeric sizing format and traditional construction associated with the car. Available BFGoodrich options in this size include blackwall and wide whitewall versions, which lets the visual presentation stay close to the era.

The right choice depends on how strictly the car is being restored and what appearance you want from the finished vehicle. A buyer chasing exact historical accuracy should compare tire details against marque references, period photos, or other vehicle-specific documentation. For many owners, though, staying with the 520-12 bias-ply format is the clearest way to preserve the car’s vintage character.

Tire construction changes the overall look of a restored 1958 Fiat 600 because bias-ply and radial tires present differently even when they fit the same 12-inch wheel diameter. A 520-12 bias-ply keeps the car in a traditional vintage format, while a 135R12 radial introduces a later Euro-metric sizing style and a different visual character.

That difference matters on a small car where the tire is a noticeable part of the stance and silhouette. Owners focused on a restoration-oriented presentation often start by deciding whether the car should retain a more traditional sidewall and profile. Once that decision is made, sidewall style, such as blackwall or wide whitewall, can refine the look without changing the basic fitment direction.

Yes, modifications can affect tire fitment on a 1958 Fiat 600 even when the tire size itself is correct. Aftermarket wheels, changes in wheel width, altered suspension height, body repairs, or steering-component differences can all influence how a 520-12 or 135R12 tire sits and clears the car.

A modified collector car should be measured rather than assumed to match original wheel and clearance conditions. Small cars tend to show changes quickly, especially around the fenders and steering arc. Before mounting new tires, check wheel diameter, wheel width, available clearance at full steering lock, and any signs that the car has already been fitted with a non-original wheel setup.

Before driving a 1958 Fiat 600 on new tires, inspect the wheels, valve stems, and visible suspension and steering components, then confirm that the tires are seated properly and inflated correctly for the setup being used. It is also smart to look over the brake hardware and wheel fasteners while the car is already off the ground.

A short, careful test drive is the next step. Listen for rubbing, feel for vibration, and recheck clearance with the steering turned through its full range. On an older car that may see limited use, it also helps to look for uneven ride height or worn components that could affect how the new tires track and wear once the Fiat returns to regular road use.

520-12 tires on a collector 1958 Fiat 600 should be kept properly inflated, inspected regularly for cracking, cuts, bulges, and air loss, and stored away from prolonged heat, sunlight, and ozone sources when the car is not being driven often. A low-mileage collector car can age tires long before it wears them out.

Maintenance also includes checking tread condition and watching for flat spotting after long storage periods. Moving the car occasionally and keeping the suspension in sound condition can help the tires maintain their shape. Before any longer drive, a close visual inspection and pressure check are worthwhile, since bias-ply collector tires are often used on vehicles that spend more time parked than on the road.