The 1955 Fiat 1400 sits in an important postwar European sedan era, when Fiat was building practical cars with more modern styling and road manners than many earlier family saloons. For owners today, tire choice is closely tied to which 1400 A & B variant is being fitted, because both radial and bias-ply sizes appear across the range. The standard 1400 A & B uses either 165R14 radial or 5.90-14 bias-ply sizing, while the diesel version steps up to 175R14 radial or 6.40-14 bias-ply. That gives buyers a real decision between period-style construction and later radial behavior, with blackwall radial choices from Pirelli, Michelin, and Vredestein.
Which Tire Size Is Right for The 1955 Fiat 1400
The 1955 Fiat 1400 uses four primary tire sizes, and the right one depends first on the exact sub-model. All four sizes mount on 14-inch rims, but fitment differs between the 1400 A & B and the 1400 A & B Diesel, with each sub-model pairing a bias-ply option and a radial option. Before choosing a tire, confirm which version of the car you have and whether you want to stay with its period bias-ply sizing or move within its radial fitment.
165R14 is a Euro-metric radial size, with 165 indicating nominal section width in millimeters, R identifying radial construction, and 14 matching the wheel diameter in inches. On the 1955 Fiat 1400, this size belongs to the 1400 A & B rather than the diesel variant, and it represents the radial fitment for that sub-model. Available choices include blackwall tires from Pirelli, Michelin, and Vredestein across series such as Cinturato CA67, Michelin XAS, and Sprint Classic. This size is the one to evaluate if your goal is radial construction with a traditional European look on the standard 1400 A & B.
5.90-14 is a numeric bias-ply size, with 5.90 representing the nominal section width in inches and 14 identifying the wheel diameter. For the 1955 Fiat 1400, this is the bias-ply fitment associated with the 1400 A & B, making it the period-style construction choice for that version of the car. Bias-ply sizing like this appeals to owners who want to preserve a more traditional tire presentation and driving character. It is the size to confirm when a standard 1400 A & B is being kept close to its earlier construction style rather than fitted with a radial.
175R14 is a Euro-metric radial size, with a 175-millimeter nominal section width, radial construction, and a 14-inch rim diameter. On the 1955 Fiat 1400, this size is used on the 1400 A & B Diesel, not the standard gasoline A & B version, so sub-model identification matters before purchase. Blackwall radial options in this size include Michelin and Vredestein offerings, including Michelin XAS plus Vredestein Sprint Plus and Sprint Classic. This is the radial size to compare when fitting a diesel model and wanting to stay within the correct 14-inch radial specification for that application.
6.40-14 is a numeric bias-ply size, with 6.40 indicating nominal section width in inches and 14 showing the wheel diameter. For the 1955 Fiat 1400, this bias-ply fitment belongs to the 1400 A & B Diesel, giving that sub-model its own period-style sizing separate from the standard A & B. Buyers considering this size are usually focused on retaining traditional construction and appearance rather than selecting a radial tire. It is the size to verify when the car is a diesel model and the goal is to preserve its bias-ply fitment rather than cross over to the diesel radial option.
Sub-model fitment matters on the 1955 Fiat 1400 because the gasoline and diesel versions do not share the same tire sizes. Both versions use 14-inch wheels and each offers a bias-ply and a radial path, but choosing correctly starts with confirming which 1400 A & B variant is in front of you.
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1955 Fiat 1400 A & B
The 1955 Fiat 1400 A & B uses its own pair of tire sizes, with 165R14 as the radial fitment and 5.90-14 as the bias-ply alternative. That gives owners a clear choice between a traditional period-style presentation and a radial setup with available blackwall European tire options.
The 1955 Fiat 1400 A & B (Diesel) steps up to a different pair of sizes, using 175R14 in radial form and 6.40-14 in bias-ply form. Tire selection for the diesel begins with confirming that larger fitment, then deciding whether the car is staying with its vintage construction style or moving within the radial size intended for that version.
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 Fiat 1400 Tires for Sale
Available 14-inch tire choices for the 1955 Fiat 1400 focus on blackwall radials from Pirelli, Michelin, and Vredestein. Across 165R14 and 175R14, buyers can compare classic European series such as Cinturato CA67, Michelin XAS, Sprint Classic, and Sprint Plus, along with rim-width and load-capacity details where shown.
These FAQs focus on the exact tire sizes used on the 1955 Fiat 1400, how fitment changes between the A & B and diesel versions, and what to compare when choosing between radial and bias-ply options for a restoration-minded driver.
Tire Size & Fitment
What tire size fits a 1955 Fiat 1400?
A 1955 Fiat 1400 can use 165R14, 5.90-14, 175R14, or 6.40-14, depending on the exact sub-model and whether the car is being fitted with radial or bias-ply tires. The 1400 A & B uses 165R14 radial or 5.90-14 bias-ply, while the 1400 A & B Diesel uses 175R14 radial or 6.40-14 bias-ply.
The important next step is matching the tire size to the correct version of the car rather than choosing by wheel diameter alone. All four sizes use a 14-inch rim, but the standard and diesel models do not share the same width class, so confirm the sub-model and current wheel setup before selecting a tire.
What size rim does a 1955 Fiat 1400 use?
The 1955 Fiat 1400 uses a 14-inch rim across its covered tire sizes. That includes both radial sizes, 165R14 and 175R14, as well as both bias-ply sizes, 5.90-14 and 6.40-14. Rim diameter stays consistent even though tire width and construction change between the standard and diesel versions.
That common diameter makes wheel verification simpler, but it does not make every 14-inch tire appropriate for every 1400. The buyer still needs to confirm the exact sub-model, the wheel width being used, and whether the car is staying with bias-ply construction or using the radial size associated with that specific version.
Do all 1955 Fiat 1400 sub-models use the same tire size?
No. The 1955 Fiat 1400 A & B and the 1955 Fiat 1400 A & B Diesel use different tire-size pairings. The standard A & B uses 165R14 radial or 5.90-14 bias-ply, while the diesel uses 175R14 radial or 6.40-14 bias-ply. Both share 14-inch rims, but they do not share the same tire sizes.
That distinction matters because choosing by appearance alone can lead to the wrong width and construction for the car you have. Start by confirming whether the vehicle is the gasoline A & B or the diesel version, then decide whether the goal is a period-style bias-ply setup or a radial tire within that model’s proper size range.
Bias-Ply & Radial Options
Is 5.90-14 a bias-ply or radial tire for the 1955 Fiat 1400?
On the 1955 Fiat 1400, 5.90-14 is a bias-ply tire size. It belongs to the 1400 A & B and serves as the traditional construction option for that sub-model, while 165R14 is the corresponding radial fitment. The diesel version uses its own larger bias-ply and radial pair rather than sharing this size.
That means a standard 1400 A & B owner is not only choosing a size but also choosing construction style. Bias-ply tires suit restoration-oriented goals and a more vintage presentation, while the radial alternative should be confirmed against the car’s wheels and overall setup before making a change in construction.
Should I use bias-ply or radial tires on a 1955 Fiat 1400?
Either construction can be appropriate on a 1955 Fiat 1400, but the decision depends on the exact sub-model and the result you want from the car. The 1400 A & B uses 5.90-14 bias-ply or 165R14 radial, and the diesel uses 6.40-14 bias-ply or 175R14 radial. Both paths remain within 14-inch fitment.
Bias-ply tends to make the most sense when preserving a period-style appearance and construction approach is the priority. Radial sizing is often the choice when the car will see more regular road use, but wheel width, tire clearance, and the current condition of the suspension and steering should be checked before changing construction.
What should I check before converting my 1955 Fiat 1400 from bias-ply to radial tires?
Start by confirming the correct radial size for the exact version of the car. A 1955 Fiat 1400 A & B converts within its own sizing from 5.90-14 to 165R14, while the diesel converts within its own fitment from 6.40-14 to 175R14. Both radial sizes stay on 14-inch rims, but they are not shared across the two sub-models.
Wheel width is worth checking first, followed by overall tire clearance at the fenders, steering components, and suspension. It also helps to inspect the car for aftermarket wheels, altered ride height, or worn suspension parts, since those changes can affect how a radial fits and behaves even when the nominal rim diameter is correct.
Choosing the Right Tire
What should I consider when choosing a 165R14 tire for a 1955 Fiat 1400?
A 165R14 tire belongs on the 1955 Fiat 1400 A & B, so the first consideration is confirming that the car is the standard A & B and not the diesel. From there, compare the available radial offerings by brand and series, including Pirelli Cinturato CA67, Michelin XAS, and Vredestein Sprint Classic, all in blackwall form.
Selection usually comes down to how closely the tire matches the look and use of the car. Rim-width guidance is also worth comparing, since some 165R14 products include a stated range, and load-capacity details can matter on a road-driven sedan where preserving proper wheel compatibility is just as important as preserving appearance.
What brands offer tires for the 1955 Fiat 1400?
Radial tires for the 1955 Fiat 1400 are available from Pirelli, Michelin, and Vredestein. In 165R14, the choices include Pirelli Cinturato CA67, Michelin XAS, and Vredestein Sprint Classic. In 175R14, the available brands are Michelin and Vredestein through XAS, Sprint Plus, and Sprint Classic offerings.
Brand choice should be treated as part of a broader fitment decision rather than the whole decision. Start with the correct size for the exact sub-model, then compare each brand’s available series, blackwall presentation, and any stated rim-width or load details so the tire suits both the car’s setup and the owner’s intended use.
What tire series are available for the 1955 Fiat 1400?
The 1955 Fiat 1400 has several classic radial tire series available, depending on size. Buyers looking at 165R14 can compare Pirelli Cinturato CA67, Michelin XAS, and Vredestein Sprint Classic. In 175R14, the available series include Michelin XAS plus Vredestein Sprint Plus and Vredestein Sprint Classic.
Those series differences matter most after the correct sub-model and size have been confirmed. Once that is settled, the practical comparison becomes whether the tire’s visual character, rim-width specification where stated, and overall specification details line up with the way the car will be used and the appearance the owner wants to preserve.
Restoration & Appearance
Which tire should I choose for a period-style 1955 Fiat 1400?
A period-style 1955 Fiat 1400 usually starts with the bias-ply size tied to the correct sub-model. The 1400 A & B uses 5.90-14 in bias-ply form, while the 1400 A & B Diesel uses 6.40-14. Those sizes keep the car within its traditional construction style rather than moving to the radial alternatives used on the same 14-inch wheel diameter.
That does not automatically make every bias-ply tire the right restoration choice, since appearance goals can vary from a driver-quality presentation to a more exacting historical build. When originality matters beyond basic size and construction, compare the tire’s visual style carefully and confirm details through model-specific references or marque-club guidance.
How does tire construction affect the appearance of a restored 1955 Fiat 1400?
Tire construction changes the look of a restored 1955 Fiat 1400 as much as it changes the driving feel. Bias-ply sizes such as 5.90-14 and 6.40-14 give the car a more traditional presentation, while radial sizes like 165R14 and 175R14 introduce a later European radial appearance, even though all of them remain on 14-inch rims.
That makes construction an appearance decision as well as a fitment decision. Owners restoring for period character often stay with the bias-ply path tied to their sub-model, while owners building a road car may prefer a radial, accepting that the visual impression can shift even when the tire size remains appropriate to the vehicle.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1955 Fiat 1400?
Yes. A 1955 Fiat 1400 may have the correct nominal tire size for its sub-model and still run into fitment issues if the car has aftermarket wheels, altered suspension height, or body and steering changes. That matters on both the standard and diesel versions, since their proper tire sizes are different even though all use 14-inch rims.
Wheel width and offset are two of the first things to verify on a modified car. It also helps to check fender clearance, steering sweep, and suspension travel with the vehicle at normal ride height, because a tire that suits the stock setup may behave differently once the original wheel or chassis geometry has changed.
What should I inspect before driving a 1955 Fiat 1400 on new tires?
Before driving a 1955 Fiat 1400 on new tires, inspect the wheels for correct diameter and condition, make sure the tire size matches the exact sub-model, and confirm that the tires are seated and inflated properly. It also helps to check the valve stems, balance, and general condition of the suspension and steering components.
A collector car can look ready for the road while still having age-related issues that affect how new tires perform. Examine the car for rubbing at full steering lock, uneven ride height, worn bushings, or looseness in front-end parts, then recheck pressure and any signs of interference after the first short drive.
How should 165R14, 175R14, 5.90-14, and 6.40-14 tires on a collector 1955 Fiat 1400 be maintained?
Collector-car tires on a 1955 Fiat 1400 should be maintained with regular pressure checks, visual inspections, and attention to age as well as tread. That applies whether the car is running 165R14 or 175R14 radials, or 5.90-14 or 6.40-14 bias-ply tires. Sidewall cracking, bulges, cuts, and unexplained air loss all deserve immediate attention.
Long periods of storage can be hard on tires even when the car is driven only occasionally. Keeping the Fiat away from prolonged sunlight, heat, moisture, and ozone sources helps preserve the rubber, and periodic checks for flat spotting or uneven wear make it easier to catch a problem before a local outing turns into a roadside issue.
