1959 Armstrong-Siddeley Sapphire Tires

The 1959 Armstrong-Siddeley Sapphire uses two primary tire sizes: 185R16 in radial construction and 670-16 in bias-ply construction. Both sizes are tied to 16-inch rims, so the key difference is not wheel diameter but tire sizing system and construction type.

Choosing between them starts with the actual setup on the car. A Sapphire already running radial tires may be best evaluated around 185R16 options, while a car kept in traditional bias-ply form points toward 670-16. Check the wheel width, the existing tire markings, and clearance around the front suspension and fenders before making a change.

The 1959 Armstrong-Siddeley Sapphire uses a 16-inch rim diameter with both of its primary tire sizes. That applies to the 185R16 radial fitment and the 670-16 bias-ply fitment, so wheel diameter stays consistent even though the tire constructions differ.

Rim diameter is only part of the fitment picture. Before selecting tires, confirm the wheel width as well, since the available products do not all share the same rim-width range. That matters especially when comparing a traditional bias-ply setup with a radial setup, or when the car may have had replacement wheels installed over the years.

The 1959 Armstrong-Siddeley Sapphire 346 Saloon can appear with either of the two primary sizes used on this model: 185R16 radial or 670-16 bias-ply. In other words, the saloon body does not narrow the choice to one size by itself.

That makes the individual car more important than the sub-model name alone. Look at the current wheel and tire combination, confirm whether the car is already set up around radial or bias-ply construction, and inspect wheel width before ordering replacements. A saloon restored for traditional presentation may follow one path, while a regularly driven car may follow the other.

On the 1959 Armstrong-Siddeley Sapphire, 670-16 is a bias-ply tire size. It uses the older numeric bias-ply sizing system, where the leading number refers to nominal section width and the final number identifies the 16-inch rim diameter.

That matters because a bias-ply setup carries a different look and may suit a more traditional restoration approach. Before replacing a 670-16 tire with anything else, confirm the wheel width and make sure the car has the clearance and wheel configuration needed for the tire you plan to use. Construction changes should always be treated as a setup check, not an automatic swap.

Either can be appropriate on a 1959 Armstrong-Siddeley Sapphire because both 670-16 bias-ply and 185R16 radial fitments are used on this model. The decision usually comes down to how the car is currently equipped and whether the priority is a more traditional period-style presentation or a radial-based driving setup.

A bias-ply tire keeps the vintage sizing and construction character, while a radial follows a later tire design in the same 16-inch wheel diameter. The right choice depends on wheel width, the suspension and steering clearances on the car, and how closely the owner wants to stay with the vehicle's established appearance and road-use pattern.

Start by confirming that the car's wheels are suitable for the radial size under consideration, since the Sapphire's radial and bias-ply fitments differ by more than construction alone. The primary radial fitment is 185R16, so wheel width and current tire markings should be checked before assuming a conversion is appropriate.

Also inspect suspension condition, steering travel, and clearance at the fenders and inner wheel housings. A car that has been lowered, fitted with replacement wheels, or altered during restoration deserves extra attention before moving away from 670-16 bias-ply tires. The goal is to confirm compatibility with the actual vehicle, not just the nominal 16-inch rim diameter.

Start with the correct primary size and construction for the car as it sits today: 185R16 if it is set up around radial fitment, or 670-16 if it remains in bias-ply form. Both use 16-inch rims, but they represent different sizing systems, different product ranges, and different restoration directions.

From there, compare the available brands, tire series, sidewall presentation, and wheel-width suitability. Michelin, Avon, Vredestein, and Firestone all appear in the Sapphire's applicable sizes, but not in the same construction or product family. A good selection process balances appearance, wheel compatibility, and the kind of road use the car is expected to see.

Tires for the 1959 Armstrong-Siddeley Sapphire are available from Michelin, Avon, Vredestein, and Firestone. The radial 185R16 fitment includes Michelin, Avon, and Vredestein options, while the bias-ply 670-16 fitment includes Firestone and Avon choices.

Brand matters mainly as part of a larger selection picture rather than as a ranking exercise. It is more useful to compare which brand appears in the size and construction you need, then look at tire series, blackwall presentation, and wheel-width compatibility. That approach helps keep the choice centered on fitment and intended vehicle character rather than label alone.

The 1959 Armstrong-Siddeley Sapphire has access to several distinct tire series depending on size and construction. In 185R16 radial form, the options include Michelin X Radial, Avon Turbosteel CR6D, and Vredestein Sprint Classic. In 670-16 bias-ply form, available series include Firestone Classic Bias Ply and Avon Turbospeed Mk4.

Series names are useful because they separate a traditional bias-ply presentation from a classic radial touring-style option. Once the correct size and construction are established, comparing series helps narrow the field by intended look and wheel compatibility. It is also a practical way to keep a restoration-oriented car visually coherent without overstating originality.

For a period-style 1959 Armstrong-Siddeley Sapphire, 670-16 bias-ply tires are the most natural starting point because they preserve the vintage numeric sizing system and traditional bias-ply construction used on this model. Blackwall choices in that size maintain the formal late-1950s saloon presentation without introducing a visibly modern metric sidewall format.

That said, period-style is not the same as proven factory originality. When exact restoration accuracy matters, compare the tire choice against marque-specific references, surviving photos, and restoration records for the individual car. If the priority is preserving an authentic overall impression, staying with the proper size, construction family, and blackwall appearance usually matters most.

Tire construction changes the visual character of a restored 1959 Armstrong-Siddeley Sapphire more than many owners expect. A 670-16 bias-ply tire keeps the older numeric size format and a more traditional presentation, while a 185R16 radial introduces a later metric-style sidewall marking even though both use the same 16-inch rim diameter.

That visual difference can influence how formal or period-minded the finished car feels, especially on a British saloon with restrained styling. For many restorations, the decision is not simply about road manners but about whether the tire should read as authentically vintage at a glance. Sidewall treatment remains simple here, since the applicable choices are blackwalls.

Yes, modifications can affect tire fitment on a 1959 Armstrong-Siddeley Sapphire even when the nominal rim diameter remains 16 inches. Replacement wheels, altered wheel width, suspension work, ride-height changes, or body repairs can all influence whether a 185R16 radial or 670-16 bias-ply tire is still the appropriate choice.

A Sapphire that has been restored or updated over time should be checked as an individual car, not treated as untouched by default. Measure the existing wheel width, verify steering and fender clearance, and inspect how close the current tires run to suspension components. Those checks become especially important when changing construction type or moving from one size system to another.

Before taking a 1959 Armstrong-Siddeley Sapphire onto the road on new tires, inspect the wheels for damage, confirm the wheel nuts are properly secured, and make sure inflation pressure matches the tire being used. It is also wise to check that the tires clear the fenders, steering components, and suspension through a full range of motion.

The rest of the car deserves attention too, especially on a low-use collector saloon. Look over the steering, brakes, shocks, bushings, and wheel bearings so the new tires are not asked to mask unrelated mechanical issues. A short local test drive is a sensible first step before any sustained run, particularly if the car has changed from bias-ply to radial construction.

Collector-car tires on a 1959 Armstrong-Siddeley Sapphire should be inspected regularly for cracking, bulges, cuts, uneven wear, and gradual air loss, even if the car is driven sparingly. Long periods of storage can age tires from time and environment alone, so condition matters as much as tread depth on a vehicle of this era.

Good storage habits help preserve both radial and bias-ply tires. Keep the car away from prolonged sunlight, excess heat, moisture, and ozone sources such as electric motors or welders, and check pressures before each drive rather than assuming they have held. A Sapphire that sits for extended periods benefits from frequent visual checks and occasional movement to avoid neglect-related surprises.