1964 Fiat 1800 Tires

The 1964 Fiat 1800 uses more than one tire size, and the correct fitment depends on the sub-model. The B Sedan uses 165R15 in radial form or 590-15 in bias-ply form, while the Wagon uses 175R14 in radial form or 6.40-14 in bias-ply form. Those are two different wheel-diameter families, so they should not be treated as one universal fitment.

The practical first step is confirming whether the car is a B Sedan or a Wagon, then checking the actual wheel diameter on the vehicle. Many older cars have been changed over the years, so the current wheel setup matters just as much as the intended tire construction when narrowing the choice.

A 1964 Fiat 1800 uses either a 15-inch or a 14-inch rim, depending on the sub-model. The B Sedan is associated with 15-inch tire sizes, while the Wagon is associated with 14-inch tire sizes. Both radial and bias-ply fitments exist within each of those rim diameters, so the wheel itself is one of the key pieces of the decision.

Measuring the wheel before ordering tires is important, especially on a collector car that may no longer have its original wheels. Rim width also matters once the diameter is confirmed, because individual tire choices within these sizes can have different wheel-width requirements even when the diameter matches.

The 1964 Fiat 1800 has more than one tire size because fitment changes by sub-model and by tire construction. The B Sedan uses a 15-inch size family, while the Wagon uses a 14-inch size family. Within each sub-model, one size is radial and the other is bias-ply, so the variation is not random or interchangeable.

That means the right choice starts with identifying the exact body style and then deciding whether the car is being kept in a traditional bias-ply setup or a radial one. Checking the wheel diameter on the car helps prevent confusion, especially if the vehicle has seen wheel changes during restoration or regular use.

590-15 is a bias-ply tire size for the 1964 Fiat 1800 B Sedan. It is the traditional 15-inch bias-ply fitment paired with that sub-model, while 165R15 serves as the radial fitment in the same general wheel-diameter family. The size format itself is also a clue, since 590-15 uses the older numeric bias-ply style rather than a modern radial designation.

Choosing 590-15 usually points toward a more traditional driving and appearance goal, while the radial alternative may appeal to owners taking a different approach. The key is to confirm the car still uses the correct 15-inch wheel setup and that the wheel width matches the tire being considered.

Radial equivalents for 590-15 include 165R15, P165/75R15, and P175/70R15. Those options cover three different sizing approaches: an 80-series metric radial, a 75-series P-metric radial, and a 70-series P-metric radial. Each one belongs to the same general equivalency group for owners evaluating a radial alternative to the original 15-inch bias-ply size.

A recommended rim-width range of 4 to 5 inches applies to that equivalent group, which makes wheel confirmation especially important before changing size format. Overall tire dimensions, steering clearance, and fender space should also be checked carefully, since an equivalent is a comparison point rather than an automatic one-for-one substitution.

Start by confirming the exact sub-model, wheel diameter, and current bias-ply size on the car. A 590-15 Sedan conversion points into the 15-inch radial equivalent family, while a Wagon using 6.40-14 should remain within its own 14-inch fitment path. The correct radial choice depends on matching the wheel and the intended tire format, not simply switching constructions.

Wheel width, overall tire dimensions, steering clearance, and fender clearance all deserve attention before making the change. Suspension condition also matters on an older Fiat, because worn components can affect how a different construction behaves and how much room is available once the car is back on the road.

The biggest factors are sub-model, wheel diameter, and construction type. A 1964 Fiat 1800 B Sedan uses 15-inch sizes, while the Wagon uses 14-inch sizes, and each has both a bias-ply and a radial path. Once the correct size family is established, the choice becomes more about how the car is used and how traditional or modern the finished setup should feel.

After fitment is narrowed down, compare wheel-width requirements, sidewall style, brand, and tire series within the correct size. A restoration-oriented car may lean toward a period-style presentation, while a road-driven example may call for a radial in the proper size family and a sidewall treatment that suits the car's overall appearance.

Sidewall choice varies by size, but the 1964 Fiat 1800 has blackwall, narrow whitewall, and wide whitewall options available across its applicable tire range. The broadest sidewall variety appears in 165R15, while 590-15 also offers blackwall and wide whitewall choices. The Wagon's 175R14 radial options shown here are blackwall-focused.

That makes sidewall style an appearance decision after the correct size and wheel diameter are confirmed. Whitewall width can change the car's presentation noticeably, so many buyers choose that detail with the restoration theme in mind rather than treating it as a purely technical specification.

Brands available across 1964 Fiat 1800 fitments include Coker Classic, American Classic, Firestone, BFGoodrich, Michelin, Vredestein, and Avon. The exact brand selection depends on the tire size, since the 15-inch radial Sedan fitment has the widest assortment, while the other sizes are narrower in scope. Brand choice therefore follows the fitment decision rather than replacing it.

Once the correct size is established, comparing brands is most useful when tied to series, sidewall treatment, and wheel-width compatibility. That approach keeps the decision grounded in how the tire will look and fit on the car, instead of turning it into a brand-only comparison without regard to the Fiat's actual setup.

For a period-style 1964 Fiat 1800, the starting point is the correct sub-model size family and the traditional construction associated with it. That means 590-15 for the B Sedan or 6.40-14 for the Wagon if the goal is to keep a bias-ply presentation. Those sizes preserve the older tire format that suits the car's era visually.

Appearance still depends on details such as blackwall versus whitewall where those options exist, especially on the 15-inch Sedan fitment. Buyers pursuing strict originality should compare the final choice against marque references or restoration documentation, since a period-style tire can be appropriate in look without automatically being exact to every car.

Tire construction changes more than ride and handling on a restored 1964 Fiat 1800; it also changes the visual character of the car. A bias-ply size such as 590-15 or 6.40-14 gives a more traditional presentation, while radial sizes like 165R15 and 175R14 tend to create a more modern-looking sidewall and overall stance.

Sidewall treatment adds another layer to that decision, especially on 165R15 where blackwall, narrow whitewall, and wide whitewall choices are available. Matching construction to the restoration goal usually produces a more coherent result than choosing by size alone, particularly on a European sedan or wagon from this period.

Yes, modifications can affect tire fitment on a 1964 Fiat 1800, especially because the car already has distinct 14-inch and 15-inch fitment paths depending on sub-model. Aftermarket wheels, wheel-width changes, suspension alterations, or body adjustments can all change which tire sizes remain practical. That is particularly important when moving between bias-ply and radial constructions.

A modified car should be checked for actual wheel diameter, wheel width, and available clearance before choosing a tire. Steering lock, fender space, and suspension travel are worth reviewing as well, since a collector vehicle may have been altered years ago and no longer match its original-style fitment assumptions.

Before driving a 1964 Fiat 1800 on new tires, inspect the wheels for correct diameter, visible damage, and proper seating surfaces, then verify that the tires match the car's actual sub-model fitment. It also helps to check valve stems, lug hardware, and inflation pressure so the basic installation is sound before the car goes back into regular use.

A slow walk-around after installation is worthwhile on an older Fiat. Look for clearance at the front wheels during turning, confirm there is no contact under normal suspension movement, and keep an eye on early air loss or unusual wear patterns during the first drives as the setup settles in.

Tires on a collector 1964 Fiat 1800 should be checked regularly for pressure, cracking, cuts, bulges, tread condition, and signs of air loss, even if the car is driven only occasionally. Low-use classics can age out before they wear out, so condition matters at least as much as mileage when judging whether the tires are still roadworthy.

Storage also plays a big role in long-term tire health. Keeping the car away from prolonged sunlight, excess heat, moisture, and ozone sources helps preserve the rubber, and occasional inspections of the spare and the mounted tires can catch issues early before a weekend drive or longer trip.