1963 Alvis TD 21 Tires

The 1963 Alvis TD 21 uses two primary tire sizes: 640-15 and 670-15. Both are bias-ply sizes built for 15-inch rims, and both are associated with the TD 21 Base. That means the car is not limited to one universal size across every example in the same simple way a single-size fitment would be.

The practical next step is to confirm what is actually on the car now, including the tire size and wheel dimensions. Many collector cars have seen wheel changes, tire substitutions, or restoration work over time, so matching the replacement tire to the existing wheel setup and checking clearance is more useful than relying on assumption alone.

The 1963 Alvis TD 21 uses a 15-inch rim diameter with its primary tire fitments. Both 640-15 and 670-15 are 15-inch bias-ply sizes, so the final number in each size refers to the wheel diameter rather than a separate tire dimension. That shared rim diameter keeps the fitment family consistent even though two tire widths are associated with the car.

Rim diameter is only part of the picture, especially on a vintage touring car. Wheel width should also be checked before choosing between available bias-ply tires or moving to a radial equivalent, since product specifications and equivalent recommendations vary. Confirming the wheel itself helps avoid choosing a tire that is correct in diameter but mismatched in overall setup.

On a 1963 Alvis TD 21, 640-15 is a numeric bias-ply tire size. The 640 indicates an approximate 6.40-inch nominal section width, while the 15 refers to a 15-inch wheel diameter. It is an older sizing format common to period vehicles, so it does not read like a modern metric radial size such as 175R15 or P175/75R15.

Understanding that format helps when comparing replacement choices. A buyer looking at 640-15 can stay with a traditional bias-ply tire for a vintage look and feel, or compare the radial equivalents tied to that same size. The decision should still be checked against wheel width, vehicle clearance, and the way the car is intended to be driven.

For the 1963 Alvis TD 21, 640-15 is a bias-ply tire size. It belongs to the older numeric bias-ply sizing system used on many mid-century cars, and the primary products available in this size are traditional bias-ply offerings. Radial choices related to 640-15 appear as equivalents rather than as the primary original-style construction.

That distinction matters because staying with bias-ply preserves the period tire format and traditional presentation, while moving to a radial means evaluating an alternative size format. The wheel must still be suitable for the radial option under consideration, and overall dimensions and body clearance should be checked rather than assumed from the shared 15-inch rim diameter alone.

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. These give the 1963 Alvis TD 21 owner several ways to compare a modern radial format against the original-style bias-ply size.

Each of those alternatives should be treated as a fitment option to evaluate, not as an automatic substitute. The recommended rim-width range for the 670-15 equivalent group is 5-7 inches, so wheel width is a key checkpoint. Clearance at the fenders and steering components also deserves attention before switching construction or profile.

Start by confirming which primary size the car uses now, since 640-15 and 670-15 have different radial-equivalent groups. Then verify the wheel diameter and width, because the equivalent recommendations include specific rim-width ranges. A radial conversion on a 1963 Alvis TD 21 should also account for the exact tire size being considered, not just the fact that it is built for a 15-inch wheel.

Condition and space matter just as much as size. Check suspension wear, steering clearance, and fender clearance, especially on a car that may have had restoration work or wheel changes over the years. It also helps to decide whether the goal is modern radial behavior, a lower-profile metric look, or a more traditional appearance such as the 670R15 bias-look radial.

The first consideration is whether the car uses 640-15 or 670-15, since both sizes are associated with the 1963 Alvis TD 21. After that, the main decisions are construction, sidewall appearance, brand, and tire series. Buyers staying with a period-style bias-ply setup can choose among blackwall, narrow whitewall, and wide whitewall options depending on the size selected.

Road use and presentation usually shape the final choice. A restoration-oriented car may call for a traditional bias-ply look, while a touring-focused car may lead the owner to compare one of the radial equivalents instead. Wheel width, load capacity figures where shown, and the condition of the car’s suspension and steering all deserve a quick review before settling on one tire.

Tires for the 1963 Alvis TD 21 are available in blackwall, narrow whitewall, and wide whitewall styles. That variety appears across both primary sizes, though the broader range of sidewall treatments is found in 670-15. This gives the car owner a meaningful appearance choice rather than limiting the decision to construction and size alone.

Sidewall style affects how the car presents visually, especially on a refined 1960s British grand tourer. A blackwall tends to give a more understated look, while narrow and wide whitewalls create a more formal period-style presentation. The best choice depends on the car’s restoration direction, wheel covers or trim, and whether the goal is subtle touring elegance or stronger vintage contrast.

The 1963 Alvis TD 21 has tire choices from BFGoodrich, Firestone, Avon, Excelsior, US Royal, Coker Classic, Universal Vintage Tire, Goodyear, and STA, depending on the size selected. Brand availability is broader in 670-15 than in 640-15, and the available products also vary by sidewall style and tire series rather than by brand name alone.

That makes brand one part of the decision, not the whole decision. It helps to compare the exact size, sidewall treatment, construction, and wheel-width suitability before focusing on styling preferences. For a car like the TD 21, the right tire often comes from balancing authentic-looking proportions with the way the car will actually be used on the road.

For a period-style 1963 Alvis TD 21, the starting point is one of the two primary bias-ply sizes used on the car: 640-15 or 670-15. Staying within those numeric bias-ply sizes preserves the original-style construction format and keeps the car visually aligned with its era. From there, the appearance can be refined through blackwall, narrow whitewall, or wide whitewall choices.

The most suitable selection depends on how strictly the car is being restored and how it is trimmed. If exact historical presentation matters, marque references, period photography, and restoration records are worth checking before settling on a sidewall treatment. For many owners, the goal is a convincing period-style look rather than proving one precise factory-delivered tire configuration.

Tire construction changes more than ride character on a restored 1963 Alvis TD 21; it also changes how the car looks. A bias-ply tire keeps the vintage numeric sizing format and traditional sidewall presentation associated with the car’s era. A radial equivalent can alter the visual character through a more modern sizing convention, even when the rim diameter remains 15 inches.

That is why construction choice should match the restoration goal. A bias-ply setup usually suits an owner focused on traditional appearance, while a radial may appeal to someone who wants modernized road use with less emphasis on preserving period tire character. Looking at the tire in profile on the actual wheel is often as important as comparing the size code itself.

Yes, modifications can affect tire fitment on a 1963 Alvis TD 21 even when the car remains within a 15-inch wheel diameter. Aftermarket wheels, altered wheel width, suspension work, ride-height changes, or body repairs can all change how a 640-15, 670-15, or radial-equivalent tire sits in the wheel opening. That is especially important on older cars that may have changed over decades of ownership.

A replacement tire should be chosen around the car’s current configuration, not only its original fitment family. Checking wheel width, steering travel, and clearance at the fenders and suspension helps prevent surprises. Any move from bias-ply to radial also deserves a fresh look at available space, since construction changes can affect how the tire occupies the wheelwell.

Before driving a 1963 Alvis TD 21 on new tires, inspect the wheels for correct diameter and general condition, and confirm that the tires are inflated appropriately for the product being used. It also makes sense to look over suspension and steering components, since worn bushings, loose steering parts, or alignment issues can affect how a vintage car responds on fresh tires.

A careful walkaround after installation is worthwhile. Check for sidewall clearance at full steering lock, confirm that the tires seat properly on the wheels, and look for any signs of rubbing once the car is on the ground. After the first drive, recheck pressure and inspect for unusual marks or air loss so small setup issues are caught early.

Collector-car tires on a 1963 Alvis TD 21 should be maintained with regular pressure checks, visual inspections, and attention to age as well as tread condition. Whether the car uses 640-15 or 670-15, watch for cracking, bulges, cuts, flat spotting, or unexplained air loss. A low-mileage vintage car can still have tire issues simply from long storage and limited use.

Storage conditions play a big role in long-term tire health. Keeping the car away from prolonged heat, direct sunlight, excess moisture, and ozone sources helps preserve the tires between drives. It is also smart to inspect the car before any longer outing, since a collector vehicle may spend weeks or months parked before returning to regular road use.