1961 Alvis TD 21 Tires

The 1961 Alvis TD 21 uses two primary tire sizes: 640-15 and 670-15. Both are bias-ply sizes built for 15-inch rims, and the TD 21 Base is associated with both of them rather than a single universal fitment.

That means the safest starting point is the actual wheel and tire setup on the car in front of you. A TD 21 that has been restored, re-wheeled, or changed over time may favor one size over the other, so confirm the current rim dimensions and compare the tire’s physical fit before choosing between the narrower 640-15 and the larger 670-15.

The primary tire fitments for a 1961 Alvis TD 21 are built around a 15-inch rim diameter. Both 640-15 and 670-15 use that same 15-inch rim size, so the wheel diameter remains consistent even though the tire sizes differ.

Rim diameter is only part of the fitment picture, especially on a collector car that may have seen changes over the years. Wheel width still matters when choosing among available tires or considering radial equivalents, so it is worth measuring the actual wheels and checking that the tire’s rim-width requirements align with the setup already on the car.

Both 640-15 and 670-15 are vintage numeric bias-ply tire sizes. In this format, the first number refers to the tire’s nominal section width in inches with the decimal omitted, while the final number indicates the 15-inch rim diameter.

For a 1961 Alvis TD 21, that means 640-15 represents a narrower bias-ply fitment than 670-15, even though both mount on the same rim diameter. Understanding that difference helps when comparing stance, appearance, wheel-width suitability, and radial-equivalent alternatives, especially if the car no longer wears the same tire size it used earlier in its life.

Both 640-15 and 670-15 are primary bias-ply tire sizes for the 1961 Alvis TD 21. They belong to the traditional numeric sizing system and keep the car in its original fitment style rather than switching it to a modern radial construction.

That distinction matters because a bias-ply tire affects not only appearance but also the feel of the car on the road. Buyers aiming for a period-style presentation often stay with bias-ply, while those exploring a radial alternative should compare the equivalent size carefully and confirm wheel width, clearance, and overall compatibility before making the change.

For 640-15, radial equivalents include 175R15, P175/75R15, and P185/70R15. For 670-15, radial equivalents include 195R15, P205/75R15, P215/70R15, and 670R15, with the 670R15 serving as the bias-look radial option within that fitment family.

Those alternatives span different sizing conventions and profile families, so they should be treated as comparison choices rather than automatic substitutions. A TD 21 owner should match the intended equivalent to the car’s wheel width and then verify physical clearance at the fenders and steering range before moving from the original bias-ply size to a radial.

Start by confirming which primary size the car is using, since the radial-equivalent choices differ between 640-15 and 670-15. Then compare the wheel diameter, the recommended rim-width range for the equivalent size, and the overall space available around the tire on the car.

A conversion should also account for the car’s present condition rather than assuming it remains exactly as built. Check for aftermarket wheels, prior suspension work, uneven ride height, and any signs of rubbing with the current tires, because even a recognized radial equivalent still needs to suit the actual wheel and clearance package on that specific TD 21.

The first decision is whether the car should use 640-15 or 670-15, since both are primary 15-inch bias-ply fitments for the 1961 Alvis TD 21. After size is confirmed, compare construction style, rim-width suitability, sidewall appearance, tire series, and whether a period-style bias-ply or a radial-equivalent path better fits the car’s intended use.

A restoration-minded TD 21 may call for a tire that preserves traditional proportions and visual character, while a car used for regular road miles may push the search toward a radial alternative. Either way, the current wheel setup matters just as much as the catalog size, especially when both primary sizes are associated with the same sub-model.

1961 Alvis TD 21 tires are available in blackwall, narrow whitewall, and wide whitewall styles, depending on the size and tire series chosen. Those appearance options show up across both 640-15 and 670-15, although the broader 670-15 range offers the greatest variety.

Sidewall style changes the visual tone of the car more than many buyers expect, especially on a formal British grand tourer. Blackwalls lean understated, while whitewall treatments create a more dressed and distinctly vintage presentation, so the right choice usually depends on the restoration direction, wheel design, and the look you want the TD 21 to carry at a glance.

Tires for the 1961 Alvis TD 21 are available from brands including Firestone, BFGoodrich, Avon, Excelsior, US Royal, Goodyear, Universal Vintage Tire, Coker Classic, and STA. Brand availability varies by size, with 670-15 offering the widest spread of names and tire-series choices.

That variety is most useful when comparing appearance and specification details rather than trying to rank one brand over another. Some options focus on traditional blackwall presentation, some emphasize whitewall styling, and some differ in rim-width fitment or load figures, so the stronger comparison is the complete tire setup rather than the brand name alone.

A period-style 1961 Alvis TD 21 usually starts with one of its primary bias-ply sizes, either 640-15 or 670-15, depending on the wheel and tire setup on the car. Staying with bias-ply construction preserves the traditional sizing format and the visual character most buyers expect from an early 1960s grand touring car.

From there, the appearance choice becomes more specific: blackwall for a restrained presentation, or narrow or wide whitewall for a more formal vintage look. Exact originality can vary by restoration goal, so buyers pursuing strict historical accuracy should compare the car against marque references or period photographs before settling on a sidewall treatment.

On a restored 1961 Alvis TD 21, tire construction affects both the look of the sidewall and the overall visual stance of the car. A bias-ply tire keeps the traditional numeric sizing format and period-style presentation, while a radial alternative can shift the look even when chosen as an equivalent size.

That does not make one construction universally right or wrong; it depends on the restoration’s priorities. Buyers focused on an authentic vintage impression often remain with bias-ply, while those seeking a different road-use balance may look at radials, ideally after confirming that the equivalent still suits the wheel, proportions, and visual character they want the TD 21 to retain.

Yes, modifications can change tire fitment on a 1961 Alvis TD 21 even when the car is staying within its primary 15-inch wheel diameter. Wheel-width changes, different offsets, suspension work, ride-height changes, or body repairs can all affect how comfortably either 640-15 or 670-15 sits in the car.

That matters even more when considering a radial equivalent, since the conversion should match the actual car rather than a theoretical stock setup. A good check includes measuring the wheels, looking for past rubbing marks, and turning the steering through its full range so clearance issues appear before the new tires go into service.

Before driving a 1961 Alvis TD 21 on new tires, inspect the wheels for correct diameter and sound condition, then verify that the tires seat properly and hold pressure consistently. It also makes sense to check for suspension wear, loose steering components, and any existing clearance issue that could affect the chosen size.

A collector car can hide problems when it has spent long periods parked, so a road-use inspection should include tread and sidewall condition on any remaining older tires, visible cracking, bulges, and signs of air loss. After installation, a short initial drive followed by another clearance and pressure check is a sensible way to confirm the setup is behaving properly.

Collector-car tires on a 1961 Alvis TD 21 benefit from regular pressure checks, visual inspections, and careful storage habits. Whether the car is running 640-15 or 670-15, the tires should be watched for cracking, flat-spotting, cuts, bulges, uneven wear, and any slow air loss that might be easy to miss on an infrequently driven car.

Storage conditions matter almost as much as mileage on a vintage touring car. Keeping the TD 21 away from prolonged sunlight, excess heat, moisture, and ozone sources helps preserve the rubber, and periodic inspection is worthwhile even when the car is not being driven often, since age and environment can affect tire condition long before the tread looks worn.