1963 Humber Hawk Tires

The 1963 Humber Hawk uses two primary tire sizes: 175R15 in radial construction and 640-15 in bias-ply construction. Both are 15-inch tire sizes, so the main difference is not wheel diameter but the construction type and sizing format tied to the tire you want to run on the car.

Choosing between them starts with the car’s current wheel setup and the type of driving and appearance you want. A 640-15 keeps the traditional numeric bias-ply format, while 175R15 uses a radial metric format. It is smart to confirm wheel width, existing clearance, and whether the Hawk still has its original-type wheel and suspension arrangement before making a change.

The 1963 Humber Hawk uses a 15-inch rim diameter with both of its primary tire sizes. That applies whether the car is running a 640-15 bias-ply tire or a 175R15 radial tire, so the wheel diameter remains consistent even though the tire construction and sizing system can differ.

Rim diameter is only part of the fitment picture, especially on an older British saloon. Wheel width also matters, particularly if the car has been changed over the years or fitted with non-original wheels. Before selecting a tire, confirm the actual wheel width on the car and compare it with the tire’s rim-width guidance so the full combination works together properly.

The 1963 Humber Hawk Base is associated with both 175R15 radial and 640-15 bias-ply fitments. Rather than separating into different sub-model tire sizes, the Base model can be found with either construction approach, both using the same 15-inch wheel diameter.

That makes the real question less about trim level and more about how the individual car is equipped today. A Hawk that has remained bias-ply may call for a different selection process than one already running radials. Looking at the current tire size, checking wheel width, and confirming available clearance will help narrow the choice before ordering replacements.

640-15 is a bias-ply tire size for the 1963 Humber Hawk. It uses the older numeric sizing system common to mid-century vehicles, and it is the traditional fitment format for owners who want to preserve the car’s vintage tire presentation on its 15-inch wheels.

That distinction matters because a bias-ply setup influences both appearance and tire selection. The 640-15 size is available in several bias-ply series and sidewall treatments, including blackwall and whitewall versions. Anyone moving away from that format should compare wheel width, tire dimensions, and clearance carefully rather than assuming every radial alternative will behave the same on the car.

Radial equivalents for the 1963 Humber Hawk’s 640-15 size include 175R15, P175/75R15, and P185/70R15. Those represent three different radial sizing approaches: an 80-series metric radial, a 75-series P-metric radial, and a 70-series P-metric radial, all intended as comparison points to the original bias-ply size.

The recommended rim-width range for those equivalent-size comparisons is 5 to 6 inches, which makes wheel measurement an important part of the decision. Even when the rim diameter matches, the car still needs enough room for steering and body clearance. A radial equivalent can be a useful alternative, but it should be checked against the Hawk’s actual wheel and chassis setup first.

The 1963 Humber Hawk can be approached either way, since 640-15 bias-ply and 175R15 radial fitments are both associated with the car. Bias-ply keeps the traditional vintage sizing format and a more period-style look, while radial sizing gives the Hawk a modern tire construction within the same 15-inch wheel diameter.

The better choice depends on your priorities. A restoration-oriented owner may prefer the visual character of a numeric bias-ply tire, especially when sidewall style is part of the presentation. A driver-focused owner may prefer to evaluate the radial route. Either way, confirm wheel width, tire dimensions, and clearance before changing construction so the result suits the car as equipped.

A 640-15 tire for a 1963 Humber Hawk should first be chosen by confirming that the car is staying with its bias-ply fitment rather than moving to a radial alternative. Once the size is settled, the main comparisons are brand, tire series, sidewall treatment, rim-width suitability, and load figures where those specifications are shown.

This size is available in several period-style presentations, including blackwall, narrow whitewall, and wide whitewall. That means the tire can influence the car’s look as much as its fitment. It also helps to compare product details such as weight and stated load capacity, then match those details to the Hawk’s current wheels and the way the car is actually used.

For the 1963 Humber Hawk’s 640-15 bias-ply fitment, available sidewall styles include blackwall, narrow whitewall, and wide whitewall. Those choices give the owner flexibility in how formal, understated, or more decorative the tire looks once mounted on the car’s 15-inch wheels.

Sidewall style can change the whole visual impression of a large early-1960s British saloon, so appearance matters as much as size here. A blackwall keeps things restrained, while whitewall variations create a more dressed look. When originality is important, compare the tire choice against period photos or marque references for your particular car before settling on a sidewall treatment.

The 1963 Humber Hawk’s 640-15 bias-ply size is available from BFGoodrich, Firestone, Avon, and Excelsior. Those brands appear across several vintage tire series, which gives the owner more than one path to a traditional replacement depending on the desired sidewall treatment and overall presentation.

Brand choice is best handled as part of the full fitment decision instead of as a stand-alone preference. Compare the available series, sidewall styles, and rim-width guidance within the same 640-15 size, then match them to the car’s look and wheel setup. That approach keeps the selection grounded in what actually suits the Humber rather than chasing a name alone.

For a period-style 1963 Humber Hawk, the 640-15 bias-ply fitment is the natural starting point because it preserves the car’s vintage numeric tire format and traditional construction. Within that size, the choice then shifts to the look you want, including blackwall, narrow whitewall, or wide whitewall versions.

That decision affects the car’s visual balance more than many owners expect, especially on a formal sedan with generous sidewall exposure. A period-style result does not automatically mean one exact sidewall treatment for every Hawk, so owners pursuing high-detail authenticity should compare their tire choice with period photography, marque-club guidance, or other vehicle-specific historical references.

Tire construction changes the visual character of a restored 1963 Humber Hawk because bias-ply and radial tires present the car differently even when both use a 15-inch wheel. The 640-15 bias-ply format tends to support a more traditional vintage look, while 175R15 introduces a more modern radial sizing language.

That difference matters most on a restoration where stance and sidewall presentation are part of the finished result. Owners focused on road use may still prefer a radial approach, but appearance-minded buyers often begin with the bias-ply size and then refine the look through sidewall style. Checking the mounted look against the car’s trim and wheel design helps avoid a mismatched presentation.

Modifications can affect tire fitment on a 1963 Humber Hawk even when the tire size itself is correct on paper. Changes such as aftermarket wheels, different wheel widths, altered offset, suspension work, or body modifications can all influence how a 175R15 or 640-15 tire sits and clears the car.

Older cars are especially worth checking because many have been changed over decades of use. Measuring the actual wheel diameter and width on the car is a smart first step, followed by a close look at fender, steering, and suspension clearance. That is important whether the Hawk is staying with bias-ply construction or being evaluated for a radial equivalent.

Before driving a 1963 Humber Hawk on new tires, inspect the wheels, valve stems, and overall clearance around the suspension and fenders. It also helps to confirm that the tire size and construction match the intended setup, whether that means a 640-15 bias-ply arrangement or a 175R15 radial installation.

After mounting, check tire pressure, look for any signs of rubbing at full steering lock, and make sure the car tracks cleanly on a short initial drive. Collector cars that sit for long periods deserve extra attention, since wheel condition and suspension wear may not show up until the car is back on the road. A careful first inspection helps prevent avoidable fitment issues.

640-15 tires on a collector 1963 Humber Hawk should be maintained with regular pressure checks and routine visual inspection for cracks, bulges, cuts, uneven tread wear, and signs of air loss. Bias-ply collector-car tires also benefit from periodic examination even when the car is driven only occasionally.

Storage conditions matter almost as much as mileage on a low-use vintage saloon. Keeping the car away from prolonged sunlight, excess heat, moisture, and ozone sources can help preserve the tires between drives. It is also wise to inspect them before any longer outing, since age and storage history can affect roadworthiness even when tread depth still looks acceptable.