1973 Fiat 850 Tires

The 1973 Fiat 850 uses two primary tire sizes: 155R13 in radial construction and 560-13 in bias-ply construction. Both are 13-inch fitments and both apply across the covered Coupe, Sport, and Spider versions, so the choice is not tied to a different wheel diameter between sub-models.

The practical decision is choosing the tire format that suits the car's setup and purpose. A 155R13 keeps the fitment in a Euro-metric radial format, while 560-13 stays with the older numeric bias-ply look. Wheel width, current wheel type, and the appearance you want on the car should all be confirmed before selecting between them.

The 1973 Fiat 850 uses a 13-inch rim diameter with both of its primary tire sizes. That applies whether the car is running the 155R13 radial fitment or the 560-13 bias-ply fitment, so rim diameter stays consistent even though the tire constructions differ.

Diameter is only the first check, especially on a small vintage Fiat. Radial and bias-ply products can call for different wheel-width ranges, and those details matter when choosing among available tires. It is smart to confirm the actual wheel width on the car before ordering, particularly if the wheels may have been replaced at some point.

The covered 1973 Fiat 850 Coupe, Sport, and Spider applications share the same fitment choices: 155R13 radial and 560-13 bias-ply. There is no separate size split among those sub-models here, so the same two size paths apply across the group.

That consistency simplifies shopping, but it does not make every tire decision automatic. The more important question is whether the car is being kept in a bias-ply presentation or run on a radial setup, and whether the wheels on the car still match the narrower width ranges often seen on small vintage fitments.

560-13 is the bias-ply tire size used on the 1973 Fiat 850. It is the older numeric sizing format and appears in classic bias-ply product lines with whitewall treatments, making it the more traditional visual choice of the two primary sizes used on this car.

That matters because a bias-ply 560-13 is not the same type of tire as a 155R13 radial, even though both fit a 13-inch rim diameter. Buyers considering a switch should look at wheel width, overall tire dimensions, and the intended character of the car rather than treating the two constructions as automatically interchangeable.

Radial equivalents for 560-13 include 155R13 as an 80-series metric radial, P155/75R13 as a 75-series P-metric radial, and P155/70R13 as a 70-series P-metric radial. Those options give the 1973 Fiat 850 owner three different radial sizing formats to compare against the original numeric bias-ply size.

Each equivalent should be treated as an alternative to evaluate, not as an automatic swap. A recommended rim-width range of 4-5 inches accompanies these equivalents, so checking wheel width is especially important. Clearance at the fenders and steering range should also be reviewed before moving from 560-13 bias-ply fitment to a radial alternative.

Start by confirming the wheel diameter and wheel width on the car, then compare the radial size being considered against the existing 560-13 bias-ply fitment. For a 1973 Fiat 850, radial alternatives to 560-13 include 155R13, P155/75R13, and P155/70R13, and the recommended rim-width range tied to those equivalents is 4-5 inches.

A construction change can also alter the visual balance of a small vintage car, so the decision is partly functional and partly cosmetic. Steering clearance, fender clearance, suspension condition, and tire-to-body spacing deserve a careful look before conversion. Cars with replacement wheels or prior suspension work should be checked even more closely.

The first step is deciding between the two primary fitments: 155R13 radial or 560-13 bias-ply. From there, the important comparisons are wheel-width compatibility, construction type, sidewall style, and whether the car is being kept in a more traditional presentation or driven with a radial-based setup.

A small car like the 1973 Fiat 850 can look noticeably different depending on tire profile and sidewall treatment, so appearance deserves as much attention as size code. It also helps to compare available product characteristics such as load figures where stated, tire series, and blackwall versus whitewall presentation before making a final choice.

The available sidewall styles for the 1973 Fiat 850 vary by tire size and construction. The radial 155R13 choices are blackwall tires, while the bias-ply 560-13 choices include narrow whitewall and wide whitewall versions, giving the smaller Fiat distinctly different visual directions depending on the tire selected.

That sidewall choice can have a major effect on the car's overall presentation. Blackwall radials keep the look more restrained and European, while whitewall bias-ply tires add a more vintage, restoration-oriented feel. Matching the sidewall style to the era impression you want is often just as important as choosing between brands.

Michelin and Dunlop offer radial choices for the 1973 Fiat 850 in the 155R13 fitment, while BFGoodrich and Firestone offer bias-ply choices in 560-13. That spread gives the car both European-style radial options and traditional American-branded bias-ply options within the proper 13-inch fitment family.

Brand should be considered alongside construction, tire series, and sidewall appearance rather than on its own. Michelin XAS-FF and Dunlop SP Sport Aquajet serve a different purpose than BFGoodrich Silvertown Classic Bias Ply or Firestone Classic Bias Ply. The better match depends on whether the car is being styled for period appearance or selected around radial use.

A period-style 1973 Fiat 850 often starts with the 560-13 bias-ply size because it preserves the older numeric sizing format and opens the door to narrow whitewall or wide whitewall presentation. That makes it the more traditional visual path when the goal is a restoration-oriented look rather than a later radial-style interpretation.

Appearance choices still need to be balanced against the actual wheel setup and how the car will be used. Whitewall width, brand, and tire series can all change the finished look, but none should be treated as automatically factory-correct without marque-specific historical references. For exact originality, period photos and Fiat-specific restoration resources remain important.

Tire construction changes more than driving feel on a restored 1973 Fiat 850; it also changes the car's visual character. A 560-13 bias-ply brings an older small-car profile and allows whitewall styling, while a 155R13 radial presents the car in a more European blackwall format with a later tire-design look.

That difference becomes especially noticeable on a compact body with small 13-inch wheels. Owners restoring for shows, photos, or a stronger period impression often place more value on sidewall style and construction format than a casual observer might expect. The best result comes from matching tire appearance to the rest of the car's trim, stance, and intended era presentation.

Yes, modifications can affect tire fitment on a 1973 Fiat 850 even when the tire size itself is correct. Aftermarket wheels, altered wheel widths, suspension changes, ride-height adjustments, or body repairs can all influence how either a 155R13 radial or a 560-13 bias-ply sits in the wheel opening.

That is why the actual car should be checked before assuming a standard size will behave the same way on every example. Steering clearance, inner-fender space, and tire-to-body spacing deserve attention, especially on a compact vintage chassis. Cars that have been restored over many years often carry wheel changes that are easy to overlook.

Before driving a 1973 Fiat 850 on new tires, inspect the wheels for correct diameter and usable width, confirm the tires are properly seated, and set inflation to the tire maker's guidance for the chosen product. It also helps to look over the suspension, steering components, and brake hardware on a car that may have spent long periods parked.

A short low-speed test is a smart final check before regular use. Listen for rubbing during turns, feel for pull or vibration, and recheck air pressure after the first drive. On a lightweight collector car, even small issues in alignment, wheel condition, or component wear can be more noticeable once fresh tires are installed.

Tires on a collector 1973 Fiat 850 should be inspected regularly for air loss, sidewall cracking, cuts, bulges, and uneven tread wear, even if the car is driven only occasionally. Collector vehicles often age tires by time and storage conditions as much as by mileage, so visual condition matters just as much as tread depth.

Proper storage helps preserve both radial and bias-ply tires. Keeping the car away from prolonged sunlight, heat, moisture, and ozone sources can slow deterioration, and maintaining correct pressure reduces the chance of flat-spotting during longer parked periods. It is also wise to inspect the spare and any older mounted tires before longer trips.