1964 Alvis TD 21 Tires

The 1964 Alvis TD 21 uses two primary tire sizes: 640-15 and 670-15. Both are bias-ply sizes for 15-inch rims, and the Base sub-model is associated with both sizes rather than one exclusive fitment. That means the car may be encountered with either of these vintage numeric sizes depending on its wheel setup and how it has been maintained or restored.

The practical next step is to confirm what is actually on the car now, especially the wheel width and the installed tire size. On a car like the TD 21, appearance and proportions matter, so moving between 640-15 and 670-15 should be treated as a fitment choice rather than an assumption. Checking the current wheel dimensions and clearance at the body and suspension helps narrow the correct path.

The 1964 Alvis TD 21 uses a 15-inch rim diameter with both of its primary bias-ply tire sizes. That means either 640-15 or 670-15 mounts to a 15-inch wheel, even though the two tire sizes differ in nominal section width. Rim diameter is the first number to confirm before looking at sidewall style, brand, or radial-equivalent alternatives.

Diameter alone does not settle the fitment question, because wheel width still matters when choosing among available tires or considering a radial equivalent. It is worth measuring the actual wheel on the car instead of relying on assumption, especially if the TD 21 has been restored long ago or has seen wheel changes over time. That extra check helps avoid clearance and proportion surprises.

A 640-15 is a vintage numeric bias-ply tire size. The 6.40 portion refers to the tire's nominal section width in inches with the decimal omitted, and the 15 indicates the wheel diameter in inches. On a 1964 Alvis TD 21, it is one of the two primary bias-ply fitments and represents the narrower of the available size choices.

Understanding that format helps when comparing vintage tires with modern radial equivalents, because the sizing language is different even when the intended fitment role is similar. Buyers looking at a 640-15 should also think about whether they want blackwall, narrow whitewall, or wide whitewall styling, since appearance can change the car's character almost as much as the size itself.

For the 1964 Alvis TD 21, 640-15 is a primary bias-ply tire size. It belongs to the vintage numeric bias-ply sizing system and appears in several bias-ply product choices, including blackwall and whitewall versions. Radial alternatives exist for buyers who want to compare modern constructions, but the original primary fitment format in this size remains bias-ply.

That distinction matters because a radial equivalent is a different construction and uses a different sizing language, even when it is intended to fill a similar fitment role. A buyer considering a change should verify wheel width, overall tire dimensions, and chassis clearance before conversion. On a grand touring car such as the TD 21, the decision often comes down to preserving period character versus choosing a modern radial-style setup.

Radial equivalents for 670-15 include 195R15 as an 80-series metric radial, P205/75R15 as a 75-series P-metric radial, P215/70R15 as a 70-series P-metric radial, and 670R15 as a bias-look radial equivalent. Those four options give the 1964 Alvis TD 21 owner several ways to compare a modern radial format against the original 670-15 bias-ply size.

Each of those alternatives should still be treated as a fitment evaluation rather than an automatic substitute. The recommended rim-width range associated with the 670-15 equivalents is 5-7 inches, so confirming the actual wheel is especially important before making the switch. Clearance at the fenders and suspension also deserves attention, particularly on a collector car where wheel or ride-height changes may have occurred over time.

Start by confirming the car's current tire size, wheel diameter, and wheel width, then compare those measurements with the radial equivalent you are considering. For a 1964 Alvis TD 21, the available equivalent paths differ by size: 640-15 and 670-15 each have their own metric and P-metric radial alternatives, and 670-15 also has a 670R15 bias-look radial option.

The conversion decision should also include a close look at body clearance, steering clearance, suspension condition, and the car's intended use. A radial equivalent may suit touring use differently than a restoration-oriented bias-ply setup, but it should never be chosen by size name alone. Checking the wheel itself and the car's present stance helps keep the change thoughtful rather than guesswork.

The first consideration is whether the car is set up for 640-15 or 670-15, since both are primary bias-ply sizes for the 1964 Alvis TD 21. After that, the decision usually shifts to construction goals, sidewall appearance, and the character of the available tire series. Buyers trying to preserve a period-style look often stay focused on traditional bias-ply proportions and sidewall presentation.

Once the correct size is confirmed, compare wheel-width compatibility, sidewall style, and any visible differences in load figures or intended tire character. A blackwall gives the car a more restrained look, while narrow and wide whitewalls create a more dressed presentation. For a driven car, it is also worth deciding early whether a modern radial equivalent should be part of the comparison.

Tires for the 1964 Alvis TD 21 are available in blackwall, narrow whitewall, and wide whitewall styles. Those choices appear across both 640-15 and 670-15 bias-ply fitments, although the 670-15 size offers the broader range of brands and sidewall combinations. The sidewall treatment has a strong influence on how formal, sporting, or understated the car appears.

Choosing among those styles depends on the visual direction of the car as much as on size. A restoration-oriented TD 21 may call for a more traditional whitewall presentation, while a blackwall often suits a cleaner touring look. The important point is to keep the sidewall choice secondary to confirmed fitment, since the right appearance still depends on the right size and wheel setup.

Available brands for the 1964 Alvis TD 21 include BFGoodrich, Firestone, Avon, Excelsior, US Royal, Universal Vintage Tire, Coker Classic, Goodyear, and STA. Not every brand appears in both primary sizes, but the overall selection gives TD 21 owners a broad spread of vintage-style bias-ply choices. Several distinct tire series are represented as well, which helps separate appearance and specification options.

Brand choice should be made after confirming whether the car needs 640-15 or 670-15, because the larger size carries a much wider assortment. It also helps to compare sidewall style and wheel-width compatibility at the same time, since two tires from different brands may serve different visual or fitment goals. The smartest comparison is always size first, then construction, then appearance and series.

A period-style starting point for a 1964 Alvis TD 21 is one of its primary bias-ply sizes, either 640-15 or 670-15, depending on the wheel setup on the car. Bias-ply construction preserves the vintage sizing language and traditional visual character that many owners want on a British grand tourer of this era. Blackwall and whitewall options both exist, so the period look can be tailored further.

The best choice depends on how the car is being restored and what references are guiding the appearance. When exact historical presentation matters, it is wise to compare the car against marque-club guidance, period photography, or restoration records before settling on a sidewall treatment. Once the visual direction is clear, the remaining decision is choosing the correct size and product series to support it.

Tire construction changes the visual tone of a restored 1964 Alvis TD 21 more than many buyers expect. A bias-ply tire keeps the car rooted in its original-era sizing system and usually supports a more traditional sidewall profile, while a radial alternative introduces a more modern sizing convention. On a car with elegant proportions, that difference can influence the overall stance and presentation.

Appearance is only part of the decision, but it matters on a restoration-grade TD 21. Some owners prefer the authenticity of a classic bias-ply look, while others want a radial path that still respects the car's vintage character, especially in 670R15 bias-look radial form. Either way, the construction choice should follow the actual wheel setup and the intended visual standard for the finished car.

Yes, modifications can change tire fitment on a 1964 Alvis TD 21 even when the car still uses a 15-inch wheel. Aftermarket wheels, different wheel widths, altered offset, suspension work, or body changes can all affect how a 640-15, 670-15, or radial equivalent sits in the wheel opening. That is especially important on a collector car that may have been updated at some point in its life.

A careful inspection should include wheel measurements and a look at clearance during steering and suspension travel. Even subtle changes can influence how comfortably a wider or differently profiled tire works on the car. Before settling on a new set, compare the current setup against the tire's intended wheel range and make sure the fitment suits the car as it exists today.

Before driving a 1964 Alvis TD 21 on new tires, check that the tire size matches the wheel setup, the beads are properly seated, and inflation is appropriate for the tire being used. It is also worth inspecting the wheels themselves for age-related issues, distortion, or corrosion. A collector car that has spent long periods parked deserves extra attention before returning to regular road use.

The rest of the walk-around should include tread and sidewall condition, any signs of cuts or bulges, and enough clearance at the fenders and steering components to avoid contact. A short initial drive followed by another inspection is a sensible practice on a newly shod vintage car. That extra caution helps catch rubbing, settling, or pressure changes before a longer outing.

Maintenance for 640-15 or 670-15 tires on a collector 1964 Alvis TD 21 starts with regular pressure checks and visual inspections, even if the car is driven infrequently. Collector vehicles often age tires through time and storage rather than mileage, so sidewall cracking, flat spotting, and slow air loss matter just as much as tread wear. Bias-ply tires deserve especially consistent monitoring when the car sits for long periods.

Storage conditions also play a major role in preserving the tires. Keeping the TD 21 away from prolonged sunlight, excessive heat, moisture, and ozone sources can help protect sidewall condition between drives. Before any tour or extended road use, inspect each tire closely and confirm the car has not developed clearance or suspension issues that could affect how the tires behave on the road.