1961 Humber Hawk Tires

The 1961 Humber Hawk uses two 15-inch tire sizes: 640-15 in a bias-ply format and 175R15 in a radial format. Those are the core fitment choices for this exact model, so the size question is tied closely to construction choice as well as wheel diameter.

That means the next step is confirming how the car is currently set up and what kind of result you want. A restoration-oriented Hawk may stay with the 640-15 bias-ply size for a more traditional look, while a car already set up around radial fitment may point toward 175R15. Wheel width, clearance, and suspension condition are worth checking before final selection.

The 1961 Humber Hawk uses a 15-inch rim diameter with both of its associated tire sizes. The 640-15 bias-ply size and the 175R15 radial size both center on that same 15-inch wheel diameter, so the basic wheel size remains consistent even though the tire constructions differ.

Rim diameter is only part of the fitment picture, especially on an older vehicle. The wheel’s actual width should also be checked before choosing a tire, particularly if the car has changed hands over the years or has had wheel substitutions. A 15-inch rim does not automatically mean every 15-inch tire option will be suitable for the current setup.

The 1961 Humber Hawk Base is associated with the same two fitment paths used on this model: 640-15 bias-ply and 175R15 radial. There is no separate sub-model-only tire size to sort through here, so the fitment question stays focused on tire construction and setup rather than trim variation.

That simplifies selection, but it does not remove the need to inspect the car itself. A Hawk that still has original-style wheels may lead naturally toward one choice, while a car that has already been updated for radial use may lead toward the other. Tire age, wheel width, and visible clearance around the fenders and suspension should all be reviewed.

640-15 is a bias-ply tire size for the 1961 Humber Hawk. It uses a vintage numeric bias-ply sizing convention, with the 640 referring to a nominal section width of about 6.40 inches and the 15 identifying the wheel diameter.

Choosing 640-15 keeps the car in a traditional sizing and construction format, which matters to owners focused on period-style presentation. Several 640-15 products are available with blackwall, narrow whitewall, and wide whitewall treatments, so the decision within that size becomes one of appearance and product details. Actual wheel width and vehicle condition should still be checked before installation.

Radial equivalents for 640-15 include 175R15 as an 80-series metric radial, P175/75R15 as a P-metric 75-series radial, and P185/70R15 as a P-metric 70-series radial. These are the radial-size alternatives associated with the original 640-15 bias-ply sizing conversation for the 1961 Humber Hawk.

Each equivalent uses a different sizing convention, so the choice is not purely cosmetic. The recommended rim-width range for these equivalents is 5 to 6 inches, and the car’s wheel width, overall dimensions, and available clearance should be confirmed before moving away from the original bias-ply size. An equivalent should be treated as an alternative to evaluate, not as automatic interchangeability.

That depends on how the 1961 Humber Hawk is being preserved and driven. The 640-15 size keeps the car in a traditional bias-ply format, while 175R15 represents the radial fitment path on the same 15-inch rim diameter. Both are part of the Hawk’s fitment picture, but they serve different owner priorities.

A bias-ply setup usually appeals more strongly to owners pursuing a period-style presentation, while a radial setup may suit drivers who want a different construction approach for regular road use. The deciding factors should include the wheels actually on the car, the intended use, and whether maintaining a traditional look matters more than changing construction. Clearance and wheel-width checks remain important either way.

Start with the basics: confirm that the car is staying with the 640-15 bias-ply size and that the wheel diameter is still 15 inches. From there, the meaningful differences are brand, tire series, sidewall style, rim-width specification, and product details such as load figures and weight where those factors matter to your use.

A restoration-oriented Hawk may point toward a whitewall treatment, while a more understated car may suit a blackwall tire better. BFGoodrich, Firestone, Avon, and Excelsior all appear in this size, but the right choice depends on the look you want and how closely the wheel setup matches the tire’s specifications. Comparing those details is more useful than assuming every 640-15 option is the same.

Within the available 640-15 tires for the 1961 Humber Hawk, sidewall choices include blackwall, narrow whitewall, and wide whitewall. That gives the car a broad appearance range, from a plainer, more restrained presentation to a more formal early-1960s look that suits many British saloons of the period.

The best sidewall choice depends on how the Hawk is being presented rather than on fitment alone. A wide whitewall can change the visual character of the car substantially, while blackwall keeps the tire more understated. Since sidewall style does not override size or wheel compatibility, confirm the tire’s specifications first and then use sidewall treatment to fine-tune the finished appearance.

The available 640-15 tire choices for the 1961 Humber Hawk include BFGoodrich, Firestone, Avon, and Excelsior. Those brands appear across several bias-ply series, giving owners more than one path to the correct vintage size without forcing the search into a single make or visual style.

Brand should be considered alongside the rest of the tire’s specifications rather than by name alone. Some options focus more on whitewall presentation, while others stay with blackwall styling, and rim-width details vary across the assortment. Comparing the full tire description helps more than choosing by brand first, especially when balancing period-style appearance against the car’s actual wheel setup.

For a period-style 1961 Humber Hawk, the 640-15 bias-ply size is the natural starting point because it keeps the car in a traditional vintage sizing and construction format. That size is also offered in several visual treatments, including blackwall, narrow whitewall, and wide whitewall, which can shape the finished look significantly.

The final choice depends on how the car is being restored and presented. A buyer aiming for visual authenticity should compare surviving photos, marque-club guidance, and other vehicle-specific references before settling on a sidewall treatment. It is safer to think in terms of period-style appearance than to assume a particular brand or whitewall width is automatically correct for every 1961 Hawk.

Tire construction can change the visual character of a restored 1961 Humber Hawk even when the wheel diameter stays at 15 inches. A 640-15 bias-ply keeps the car in a more traditional vintage format, while a 175R15 radial introduces a more modern tire-sizing approach that may present differently on the car.

That distinction matters most when the restoration goal is to preserve the car’s original-era feel. Owners who value a traditional silhouette often begin with the bias-ply size and then narrow the choice by sidewall style. A radial path can still be appropriate, but it should be chosen with a clear understanding that construction affects both the driving setup and the visual impression of the finished car.

Yes, modifications can affect tire fitment on a 1961 Humber Hawk even when the tire size itself is correct on paper. Aftermarket wheels, altered wheel width, suspension changes, ride-height adjustments, or bodywork differences can all influence how a 640-15 or 175R15 tire sits within the wheel opening and steering range.

That is why an older car should be checked as it exists today rather than treated as untouched. Look at the wheel size currently installed, inspect clearance at full steering lock, and note any evidence of rubbing around the fenders or suspension. A Hawk with later changes may need closer measurement before choosing between the bias-ply and radial fitment paths.

Before driving a 1961 Humber Hawk on new tires, inspect the wheels for the correct 15-inch diameter, check that wheel width suits the chosen tire, and confirm there is no visible interference around the fenders, steering, or suspension. It is also wise to look over the valve stems, wheel condition, and overall tire seating after installation.

A collector-era car deserves a broader safety check before returning to road use. Examine the suspension, steering components, and brakes, and verify that the tires are holding pressure consistently. A short, careful test drive can reveal vibration, pull, or clearance issues that are easy to miss while the car is stationary, especially after a change in construction or sidewall style.

640-15 tires on a collector 1961 Humber Hawk should be maintained with regular pressure checks, visual inspection, and careful storage habits. Bias-ply tires on a low-mileage car can age out long before they wear out, so tread depth alone is not enough. Sidewall cracking, cuts, bulges, flat spotting, and recurring air loss all deserve attention.

Collector cars benefit from being stored away from prolonged sunlight, excess heat, moisture, and ozone sources such as electric motors. Driving the car periodically can help reveal changes in feel or vibration, but any older tire should be inspected closely before a longer outing. When the condition of the tire or wheel is in doubt, a qualified tire professional should evaluate the setup before road use.