The 1930 Willys-Knight 66B Series comes from an era when smooth-running sleeve-valve engineering and dignified coachwork helped define an upscale motoring experience. For owners today, tire choice is part of preserving that distinctly pre-war character while keeping the car usable and properly presented. This Willys-Knight uses bias-ply fitments in 31X6.00 and 600-19, both tied to a 19-inch wheel setup. Available replacement choices lean toward a traditional look, including a Wide Whitewall offering in 600-19. The key is confirming which of the two period fitment formats matches the wheels and overall setup on the car before selecting a tire.
Which Tire Size Is Right for The 1930 Willys-Knight 66B Series
The 1930 Willys-Knight 66B Series uses two bias-ply tire sizes, and the first step is confirming which wheel and tire format is on the car now. Both fitments relate to a 19-inch setup, but they are expressed differently, so the real decision is identifying the exact size your Willys-Knight uses and then choosing the right period-style tire within that format.
31X6.00 is an antique diameter-by-section size, which means the first number refers to the tire's approximate overall diameter and the second number refers to its section width in inches. It is a bias-ply fitment suited to the pre-war character and driving feel expected on a 1930 Willys-Knight 66B Series. This format appeals to owners trying to stay close to an early tire presentation rather than moving into later metric sizing conventions. It is worth confirming the wheel setup already on the car, since antique sizing and numeric bias-ply sizing can look similar in use but are not the same designation.
600-19 is a numeric bias-ply size in which the leading number represents the nominal section width, about 6.00 inches, and the final number identifies a 19-inch rim. On the 1930 Willys-Knight 66B Series, this is a traditional pre-war replacement format that keeps the car in the bias-ply category. Available choices in this size include Lester products and a Wide Whitewall sidewall treatment through the Lester Classic Bias Ply series. It is a strong fitment to evaluate when period-style appearance matters and the car is already set up for the 600-19 designation.
Sub-model fitment is straightforward here because the covered 6-cylinder version uses the same two bias-ply tire sizes. Checking the exact sub-model still helps confirm that the car belongs in this fitment group before choosing between the two period size formats.
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1930 Willys-Knight 66B Series 6 Cyl.
The 1930 Willys-Knight 66B Series 6 Cyl. uses the same pair of bias-ply fitments, 31X6.00 and 600-19. That makes tire selection less about trim differences and more about confirming which size format matches the wheels and current setup on the car.
The tire sizes listed on this page assume factory-standard vehicle configuration. The following modifications may affect tire fitment and are not reflected in this guide:
Suspension changes (lowering, lift kits, spring replacements)
Body alterations (fender modifications, custom bodywork)
If your vehicle has been modified from factory specifications, verify tire clearance before purchase.
Best 1930 Willys-Knight 66B Series Tires for Sale
Available products for the 1930 Willys-Knight 66B Series focus on traditional 600-19 bias-ply replacement, with Lester offerings in the Lester Classic Bias Ply line and a Wide Whitewall sidewall treatment for a distinctly pre-war presentation.
Owners of a 1930 Willys-Knight 66B Series usually need to sort out the correct tire size format first, then compare bias-ply style, rim fitment, appearance, and road-use considerations before putting the car back into service.
Tire Size & Fitment
What tire size fits a 1930 Willys-Knight 66B Series?
The 1930 Willys-Knight 66B Series uses two bias-ply tire sizes: 31X6.00 and 600-19. Those sizes represent two period fitment formats used on this vehicle, and both belong to the traditional pre-war tire category rather than modern metric radial sizing.
The important next step is matching the tire size to the actual wheels and setup on the car. A Willys-Knight that is already running 600-19 tires should stay within that fitment unless the wheel and clearance situation are carefully checked, while a car set up for 31X6.00 should be treated as its own fitment rather than assumed to cross over automatically.
What size rim does a 1930 Willys-Knight 66B Series use?
The 1930 Willys-Knight 66B Series uses a 19-inch rim. That rim diameter is directly reflected in the 600-19 tire size, where the final number identifies the wheel diameter, and it aligns with the vehicle's pre-war bias-ply fitment pattern.
Rim diameter is only part of the picture on an older car, so it is still smart to verify the actual wheel on the vehicle before buying tires. Collector cars are often restored, repaired, or altered over time, and that can affect what size designation belongs on the wheel even when the nominal rim diameter remains 19 inches.
Does the 1930 Willys-Knight 66B Series 6 Cyl. use the same tire size?
Yes. The 1930 Willys-Knight 66B Series 6 Cyl. uses the same two bias-ply tire sizes associated with this fitment group: 31X6.00 and 600-19. There is no separate tire size split within the covered sub-model here.
That consistency makes sub-model identification simpler, but the owner still needs to confirm which of the two size formats is actually mounted on the car. Looking at the existing tire markings and wheel setup is especially important on pre-war vehicles, where antique diameter-style sizing and numeric bias-ply sizing can both appear in the same overall fitment family.
Choosing the Right Tire
What should I consider when choosing a tire for a 1930 Willys-Knight 66B Series?
Start with the exact size already required by the car: either 31X6.00 or 600-19. Both are bias-ply fitments, so the main decision is usually not bias-ply versus radial, but making sure the tire format, wheel diameter, and overall presentation match the Willys-Knight's current setup.
After size is confirmed, compare details that affect how the car looks and how the tire suits the intended use. On this application, that can include brand, tire series, and sidewall style, especially if the goal is a restoration-oriented appearance for shows, touring, or general collector use.
What sidewall styles are available for 1930 Willys-Knight 66B Series tires?
A Wide Whitewall sidewall style is available in the 600-19 fitment for the 1930 Willys-Knight 66B Series. That gives owners a traditional appearance choice that suits the visual character many pre-war cars are known for.
Sidewall style should be chosen with the car's finished look in mind rather than treated as a purely cosmetic afterthought. A wide whitewall can strongly influence the vehicle's stance and presentation, so it helps to consider whether the goal is a formal restoration-oriented look or a more restrained period-style appearance.
What brands offer tires for the 1930 Willys-Knight 66B Series?
Lester offers a tire for the 1930 Willys-Knight 66B Series in the 600-19 size. That product is part of the Lester Classic Bias Ply series and stays within the traditional bias-ply construction used on this pre-war application.
Brand matters most after the correct size has been confirmed, since fitment comes before appearance or series preference. Once the wheel and tire size are sorted out, the buyer can focus on whether the available brand and series deliver the sidewall style and presentation that suit the car's restoration or touring plans.
Restoration & Appearance
Which tire should I choose for a period-style 1930 Willys-Knight 66B Series?
A period-style 1930 Willys-Knight 66B Series should stay with the correct bias-ply size already matched to the car, either 31X6.00 or 600-19. Keeping the original style of construction is a major part of preserving the visual proportion and road-going character expected from a pre-war automobile.
Once the correct size is confirmed, appearance decisions become more specific. A 600-19 Wide Whitewall can suit a traditional pre-war presentation, but owners seeking exact originality should compare the finished tire choice against period photos, marque-club guidance, or restoration records rather than assuming every period-style option is identical to what the car wore when new.
Does correct tire fitment matter for a 1930 Willys-Knight 66B Series restoration?
Yes, correct tire fitment matters a great deal on a 1930 Willys-Knight 66B Series restoration. Tire size affects the car's stance, visual balance, and how authentically the chassis and body sit over the wheels, especially on a vehicle from the early 1930s.
Construction and sidewall treatment also shape the finished appearance. Using the right bias-ply format and an appropriate sidewall style helps the car look coherent, while an incorrect size can make even a well-restored vehicle seem visually off. That is why wheel confirmation and careful size selection should happen before judging the cosmetic details.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1930 Willys-Knight 66B Series?
Yes. Modifications can change tire fitment on a 1930 Willys-Knight 66B Series, even when the car still appears largely original. Wheel changes, brake work, suspension repairs, altered ride height, or body and fender adjustments can all influence which size works properly on the vehicle.
That matters even more on an older car using vintage bias-ply sizing, where fitment depends on more than the sidewall marking alone. Any Willys-Knight with replacement wheels or long-ago restoration changes should have its wheel diameter, wheel width, and physical clearance checked before settling on either 31X6.00 or 600-19.
What should I inspect before driving a 1930 Willys-Knight 66B Series on new tires?
Before driving a 1930 Willys-Knight 66B Series on new tires, inspect the wheels, valve stems, and overall wheel condition, then make sure the tires are mounted in the correct size for the car's setup. It is also wise to confirm that the tires clear the fenders and steering components through a full range of movement.
A road-ready check should also include inflation pressure, lug security, and a close look at the rest of the chassis. On collector vehicles that sit for long periods, worn suspension parts, brake issues, or old wheel hardware can show up as tire-related problems once the car goes back on the road.
How should tires on a collector 1930 Willys-Knight 66B Series be maintained?
Tires on a collector 1930 Willys-Knight 66B Series should be inspected regularly for air loss, tread wear, cracking, cuts, bulges, and signs of age-related deterioration. Even a car that is driven sparingly can develop tire problems simply from time, storage conditions, and long stationary periods.
Good storage habits help preserve both appearance and service life. Keeping the car away from prolonged sunlight, excess heat, moisture, and ozone sources can reduce stress on older-style tires, and routine pressure checks are especially important before a tour or longer drive after the vehicle has been parked for an extended time.
