1948 Willys 663SS Tires

The 1948 Willys 663SS uses a 670-15 tire size. That is a vintage numeric bias-ply size mounted on a 15-inch rim, and the covered 6 Cyl. sub-model uses that same primary fitment.

Because there is one primary size, the real choice is within the 670-15 category rather than between multiple factory fitments. It helps to confirm the wheel diameter on the vehicle, especially if wheels were changed over the years, and then compare sidewall style, construction, rim-width suitability, and overall appearance before selecting a tire.

The 1948 Willys 663SS uses a 15-inch rim with its 670-15 tire fitment. That rim diameter is the key wheel measurement tied directly to the primary tire size.

Rim diameter is only part of the fitment picture, so the actual wheel width still matters when comparing individual tires. Some 670-15 products are matched to narrower wheel widths than others, which is especially important on older vehicles that may have replacement wheels, mixed wheels, or long-ago service changes.

On a 1948 Willys 663SS, 670-15 is a vintage numeric bias-ply size. The 670 refers to an approximate 6.70-inch nominal section width, while the 15 refers to the wheel diameter in inches.

That older sizing format does not read like a modern metric radial, so it helps to interpret it in period terms rather than by current passenger-car conventions. Once the size is confirmed, the next step is choosing the right construction style and sidewall presentation while keeping wheel width and vehicle clearance in mind.

For the 1948 Willys 663SS, 670-15 is the primary bias-ply tire size. That construction matches the vehicle's period and is the starting point for restoration-oriented replacement in the original sizing format.

Bias-ply and radial tires are not the same thing, even when they are considered equivalent in size. Owners who want to preserve a traditional look and period driving character often stay with 670-15 bias-ply tires, while anyone considering a radial alternative should confirm wheel width, wheel condition, and available clearance before making the change.

Radial equivalents for 670-15 include 195R15, P205/75R15, P215/70R15, and 670R15. Those cover an 80-series metric radial, a 75-series P-metric radial, a 70-series P-metric radial, and a bias-look radial option.

Each equivalent represents a different sizing convention, so they should be treated as alternatives to evaluate rather than automatic substitutions. A 5-to-7-inch rim-width range is associated with the radial equivalents, and it is smart to compare wheel width, overall tire dimensions, steering clearance, and fender room before converting the vehicle.

Start by confirming the actual wheel diameter and wheel width on the vehicle, then compare those measurements with the radial equivalent being considered. For the 1948 Willys 663SS, 195R15, P205/75R15, P215/70R15, and 670R15 are the relevant radial-equivalent choices tied to the original 670-15 size.

A conversion also deserves a close look at tire clearance during straight-ahead and full-steering movement, especially on an older vehicle that may not still be on its original wheels or suspension. Matching the tire to the vehicle's intended use matters too, since some owners prioritize a traditional bias-ply presentation while others want a radial alternative.

Begin with the correct primary size, which is 670-15 for the 1948 Willys 663SS, and confirm that the tire matches the vehicle's 15-inch wheel. From there, compare bias-ply construction, sidewall style, tire series, and the rim-width range attached to each product.

Appearance and intended use usually drive the final choice. A blackwall can suit a more utilitarian presentation, while narrow or wide whitewalls create a more dressed-up period look, and differences in load figures or wheel-width suitability can matter just as much as the visual style on a road-driven vehicle.

Tires for the 1948 Willys 663SS in 670-15 are available in blackwall, narrow whitewall, and wide whitewall styles. Those sidewall treatments appear across several bias-ply brands and series in the correct primary size.

The sidewall choice changes the vehicle's visual character more than the size itself, so it is worth deciding how formal, utilitarian, or restoration-oriented the finished look should be. A whitewall should not be treated automatically as original for every surviving vehicle, but it can be an important period-style appearance choice for many postwar builds.

The 1948 Willys 663SS has 670-15 tire options from Firestone, BFGoodrich, Goodyear, US Royal, Universal Vintage Tire, Excelsior, Avon, Coker Classic, and STA. These appear across several bias-ply series, including Firestone Classic Bias Ply, Silvertown Classic Bias Ply, US Royal Classic Bias Ply, and others.

Brand alone should not be the only deciding factor. It makes more sense to compare the individual tire's sidewall treatment, rim-width suitability, load specification where stated, and the overall look you want on the vehicle, especially when several brands offer the same basic size in very different visual presentations.

A period-style starting point for a 1948 Willys 663SS is the original-format 670-15 bias-ply tire. Staying with the primary size and construction keeps the vehicle visually aligned with the late-1940s tire profile and sidewall character.

From there, the choice becomes one of presentation rather than basic fitment. Blackwall, narrow whitewall, and wide whitewall versions are all available, so the best match depends on the vehicle's finish, trim, and restoration goal, and exact originality is best checked against marque references or vehicle-specific historical documentation.

Tire construction changes the look of a restored 1948 Willys 663SS as much as the size does. A 670-15 bias-ply tire preserves the traditional profile and visual character associated with the vehicle's era, while a radial alternative usually changes the presentation even when chosen as an equivalent size.

That makes construction an appearance decision as well as a driving decision. Owners focused on a restoration-oriented finish often start with the bias-ply fitment, while a bias-look radial such as 670R15 may appeal to someone who wants a more traditional style cue without staying with full bias-ply construction.

Yes, modifications can affect tire fitment on a 1948 Willys 663SS even when the target size remains 670-15 or one of its radial equivalents. Wheel changes, different wheel widths, suspension alterations, or body and steering changes can all influence how much room the tire actually has.

That is why an older vehicle should be checked as it sits today rather than assumed to match original wheel and chassis dimensions. Clearance at the fender, suspension, and steering components deserves special attention, and any change in tire construction or equivalent size should be reviewed against the vehicle's current setup.

Before driving a 1948 Willys 663SS on new tires, inspect the wheels for correct diameter, sound condition, and proper bead-seat integrity, then confirm that the tires are mounted and inflated appropriately for the selected product. It is also wise to check lug hardware, valve stems, and visible clearance around the tire.

A short, careful shakedown drive is a smart next step on any collector-era vehicle. During that first drive, pay attention to steering response, vibration, and any sign of rubbing, then recheck air pressure and the mounted tires for contact marks or uneven seating before putting the vehicle into regular road use.

670-15 tires on a collector 1948 Willys 663SS should be inspected regularly for air loss, tread wear, sidewall cracking, bulges, cuts, and signs of age-related deterioration. Vehicles that spend long periods parked deserve extra attention because collector use patterns can hide tire condition issues until road speed and load increase.

Good storage habits matter almost as much as routine inspection. Keeping the vehicle away from prolonged sunlight, excess heat, moisture, and ozone sources helps protect the tires, and checking pressure before each drive is especially important on bias-ply applications and on older vehicles that may sit for extended stretches.