1959 De Soto MS 2-M-8 Firedome & MS 3-H-8 Fireflite Tires

The 1959 De Soto MS 2-M-8 Firedome & MS 3-H-8 Fireflite uses two primary tire sizes: 850-14 and 900-14. Both are bias-ply sizes for 14-inch wheels, and both appear on the covered Base configuration for this vehicle.

Since both sizes apply within this fitment, the real task is confirming which one matches the wheels and setup on the car today. A De Soto that has had wheel changes over the years may not still be using its earlier arrangement, so checking the mounted tire size and wheel width before ordering is the safest way to sort out the correct path.

Both primary tire sizes for the 1959 De Soto MS 2-M-8 Firedome & MS 3-H-8 Fireflite use a 14-inch rim diameter. That shared rim diameter applies to both 850-14 and 900-14, so the wheel diameter itself stays consistent even though the tire widths differ.

Rim diameter is only part of the fitment picture on a car like this. Wheel width still matters, especially because the available 850-14 and 900-14 products use different rim-width ranges, so it is worth measuring the actual wheels on the car if there is any doubt about past wheel replacement or modification.

An 850-14 is a numeric bias-ply tire size. The 850 portion refers to an approximate 8.50-inch nominal section width, and the 14 indicates the rim diameter in inches.

That format is common on late-1950s American cars and reads differently from modern metric radial sizing. On this De Soto, understanding the code helps separate the original-style primary fitment from modern radial equivalents, which use sizes such as 215R14 or P225/75R14 and should be evaluated by wheel compatibility and vehicle clearance rather than by size code alone.

For the 1959 De Soto MS 2-M-8 Firedome & MS 3-H-8 Fireflite, 850-14 is a primary bias-ply tire size. In the available period-style choices, it appears in the BFGoodrich Silvertown Classic Bias Ply line rather than as a primary radial fitment.

That matters because a buyer deciding on 850-14 is really choosing between staying with a traditional bias-ply construction or evaluating one of the radial equivalents tied to that size. The wheel diameter remains 14 inches either way, but rim width, overall dimensions, and clearance should all be reviewed before changing construction on a full-size collector car.

Radial equivalents for 850-14 include 215R14, P225/75R14, and P235/70R14. Those represent three different radial sizing approaches: an 80-series metric radial, a P-metric 75-series radial, and a P-metric 70-series radial.

Each one gives a useful comparison point for moving away from the original bias-ply format, but none should be treated as automatic interchangeability. The associated recommended rim-width range is 5-7 inches, and the vehicle should also be checked for wheel compatibility and enough steering, fender, and suspension clearance before any conversion is finalized.

Start by confirming which original size is on the car, since the radial-equivalent information applies to 850-14. The wheel diameter must remain correct, and wheel width should be checked carefully because the recommended rim-width range tied to the 850-14 radial equivalents is 5-7 inches.

A conversion also deserves a close look at overall tire dimensions, front-end clearance, suspension condition, and how the car is actually used. Cars that have been lowered, fitted with different wheels, or repaired with non-original components may react differently, so a full fitment check is more important than relying on size names alone.

Begin with the actual size the car needs, since this De Soto fitment includes both 850-14 and 900-14 in bias-ply construction on 14-inch rims. From there, compare wheel-width compatibility, load capacity, and whether the tire should preserve a traditional late-1950s appearance or support a move toward radial-equivalent sizing in the case of 850-14.

The available products also differ in sidewall presentation, which can change the car's visual balance noticeably. Measuring the wheels and checking what is currently installed will usually answer most selection questions, especially on an older car that may have seen wheel changes, suspension work, or cosmetic updates during its life.

The available bias-ply tires for this 1959 De Soto fitment come with either a wide whitewall or a narrow whitewall. Both sidewall styles are offered in 850-14 and 900-14 within the BFGoodrich Silvertown Classic Bias Ply range.

That makes sidewall choice an appearance decision as much as a fitment decision, especially on a fin-era full-size car where the whitewall has a strong effect on stance. Buyers trying to maintain a traditional look often compare the wheel and trim presentation first, then choose the whitewall width that best matches the car's overall restoration direction.

The product range is fairly focused, so the main choices are size, whitewall treatment, and the wheel-width range tied to each tire. Both 850-14 and 900-14 are available as BFGoodrich Silvertown Classic Bias Ply tires, with narrow whitewall and wide whitewall versions in each size.

A practical way to narrow the decision is to confirm the wheel setup first, then decide how much traditional visual emphasis the sidewall should have. The 850-14 products carry a 1740@32 psi maximum load figure, while 900-14 products carry 1860@32 psi, so that difference may also matter depending on the intended setup and use.

For a period-style presentation, the primary starting point is one of the original-format bias-ply sizes used on this car: 850-14 or 900-14, depending on the actual wheel and tire setup. The available BFGoodrich Silvertown Classic Bias Ply tires keep the vintage numeric sizing and traditional construction that suit a late-1950s De Soto visually.

The remaining choice is usually how much whitewall presence you want the car to show. A restoration-minded owner should confirm the car's existing wheel setup and then compare that appearance against period photos, marque-club guidance, or other vehicle-specific references if exact historical presentation is especially important.

Tire construction changes the visual character of a restored 1959 De Soto more than many owners expect. A bias-ply tire in 850-14 or 900-14 preserves the original-era sizing format and traditional profile language, while a radial equivalent for 850-14 introduces a more modern sizing convention even if the rim diameter remains the same.

That does not make one choice automatically right or wrong, but it does mean the car's finished look can shift depending on the construction selected. On a fin-era full-size car, that visual difference works together with the whitewall width, wheel covers, and ride height, so it helps to consider the complete presentation before deciding.

Yes. Even when the original fitment points to 850-14 or 900-14 on 14-inch rims, changes such as aftermarket wheels, altered wheel widths, suspension work, or body modifications can change what actually clears and functions properly on a 1959 De Soto MS 2-M-8 Firedome & MS 3-H-8 Fireflite.

A car that has been lowered, fitted with different wheel offsets, or repaired with non-original components should be measured rather than assumed. Clearance at the fenders and steering components matters just as much as nominal tire size, and that is especially true when comparing the narrower 850-14 with the wider 900-14 or considering a radial alternative.

Check the wheels for the correct 14-inch diameter and appropriate width, then inspect valve stems, wheel condition, and inflation pressure before road use. It also makes sense to verify lug hardware, look over suspension and steering components, and confirm that the tires clear properly at full steering lock.

A collector car that has sat for long periods deserves an extra walk-around after installation and again after its first short drive. Watch for uneven clearance, rubbing, air loss, or vibration, and keep an eye on alignment-related tread wear as the car returns to use after storage or recent mechanical work.

Collector-car tires should be checked regularly for pressure, sidewall cracking, cuts, bulges, and any sign of slow air loss, even when the car is driven only occasionally. That advice applies to both 850-14 and 900-14 tires on a 1959 De Soto, because low annual mileage does not prevent aging or storage-related deterioration.

Storage conditions matter almost as much as mileage on a seldom-driven car. Keeping the De Soto away from prolonged heat, direct sunlight, moisture, and ozone-producing equipment helps preserve the tires, and periodic inspections before local drives or longer outings make it easier to catch aging issues before they become road-use problems.