The 1926 Willys-Knight 70 Series comes from the heart of the pre-war American motoring era, when smooth-running sleeve-valve engineering and substantial coachwork gave cars a distinct road presence. Owners restoring or maintaining one today are usually balancing authenticity, drivability, and the realities of nearly century-old wheel and tire hardware. Tire fitment for the 1926 Willys-Knight 70 Series centers on two bias-ply sizes, 30X5.25 and 5.25-20, so the first step is confirming which wheel setup is actually on the car. Once that is settled, the decision shifts toward preserving a traditional period-style look and making sure wheel dimensions and overall fitment are carefully checked before road use.
Which Tire Size Is Right for The 1926 Willys-Knight 70 Series
The 1926 Willys-Knight 70 Series uses two primary tire sizes, and choosing correctly starts with confirming the exact wheel setup on the car. Both fitments are bias-ply, but they correspond to different sizing conventions and different rim diameters, so the first decision is not brand or appearance, but identifying whether the car is set up for 30X5.25 or 5.25-20 tires.
30X5.25 is an antique diameter-by-section size, meaning the first number refers to the tire's approximate overall diameter and the second refers to section width. On this 1926 Willys-Knight 70 Series fitment, it is a bias-ply tire that suits the look and construction style expected of many pre-war vehicles. This format differs noticeably from later numeric bias-ply sizing, so it is important not to confuse it with a 20-inch rim application. It is the right size to evaluate when the car retains the wheel setup associated with this early diameter-based designation.
5.25-20 is a numeric bias-ply size in which 5.25 refers to nominal section width in inches and 20 identifies the rim diameter. For a 1926 Willys-Knight 70 Series using this fitment, the tire keeps the traditional bias-ply construction that matches the character of a pre-war car. This sizing format will be more familiar to many vintage-tire buyers than an antique diameter-marked size, but it still requires careful wheel confirmation before selection. It becomes the correct path when the car is fitted with 20-inch rims rather than the alternate wheel arrangement.
Sub-model fitment is straightforward here because the covered 6 Cyl. version uses the same pair of primary tire sizes found on the 1926 Willys-Knight 70 Series page overall. What matters most is confirming which wheel and tire setup is actually on the car before choosing a replacement.
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1926 Willys-Knight 70 Series 6 Cyl.
The 1926 Willys-Knight 70 Series 6 Cyl. uses bias-ply tires and may be encountered with either 30X5.25 or 5.25-20 fitment. That makes wheel verification especially important, since the right replacement depends on matching the car's actual rim arrangement and preserving the proper pre-war tire presentation.
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.
Frequently Asked Questions
Common questions for the 1926 Willys-Knight 70 Series usually center on the difference between 30X5.25 and 5.25-20, how to confirm the correct rim setup, and what to inspect before putting a restored pre-war car back on the road.
Tire Size & Fitment
What tire size fits a 1926 Willys-Knight 70 Series?
The 1926 Willys-Knight 70 Series uses two primary bias-ply tire sizes: 30X5.25 and 5.25-20. Those are not alternate labels for the same fitment. They represent different sizing systems, and they also correspond to different rim arrangements, so the correct choice depends on the actual wheels installed on the car.
The practical next step is to inspect the car's wheels before ordering tires. A 30X5.25 fitment should be treated as an antique diameter-by-section application, while 5.25-20 is a numeric bias-ply size built around a 20-inch rim. On an older restoration, wheels may have been changed over time, so measuring the rim and confirming the current setup matters more than assuming every 70 Series uses the same tires.
What size rim does a 1926 Willys-Knight 70 Series use?
Rim size depends on which tire size is on the car. A 1926 Willys-Knight 70 Series using 30X5.25 corresponds to a 5.0-inch rim diameter in this fitment record, while a car using 5.25-20 is built around a 20-inch rim. That difference makes wheel confirmation essential before selecting replacement tires.
The safest approach is to check the wheel itself rather than relying on an old tire that may not match the current setup. Collector cars sometimes carry replacement wheels or older tires that were installed decades ago. Confirming rim diameter first prevents ordering the right-looking tire in the wrong size and helps keep fitment, mounting, and road clearance issues from becoming a problem later.
Why does the 1926 Willys-Knight 70 Series have more than one tire size?
The 1926 Willys-Knight 70 Series shows two primary bias-ply sizes because this fitment can appear in two different vintage sizing conventions and wheel setups: 30X5.25 and 5.25-20. That does not mean both sizes belong on the same wheel. It means the car may be equipped with one arrangement or the other.
For a buyer, the issue is not choosing whichever size seems close, but identifying what is actually mounted on the car today. Early vehicles often pass through multiple restorations, and wheels may have been swapped long ago. Once the rim diameter and current tire marking are verified, selecting the proper replacement becomes much more straightforward and helps preserve the car's intended pre-war stance and appearance.
Choosing the Right Tire
What should I consider when choosing a 30X5.25 or 5.25-20 tire for a 1926 Willys-Knight 70 Series?
The first consideration is choosing the correct primary size for the car's actual wheels. A 1926 Willys-Knight 70 Series may use either 30X5.25 or 5.25-20, and both are bias-ply fitments. Because those sizes belong to different vintage sizing systems, selection starts with wheel and rim verification rather than appearance alone.
After confirming size, focus on the condition and intended use of the car. A restoration-minded owner may prioritize a traditional period-style presentation, while a touring owner may be more concerned with fresh rubber and careful road readiness. It also helps to inspect wheel condition, confirm that all four wheels match, and make sure the chosen tire works with the car's current stance and clearances.
How do I choose between the available 1926 Willys-Knight 70 Series tire sizes?
Choosing between the available sizes is really a matter of identifying the proper fitment, not selecting between two interchangeable options. The 1926 Willys-Knight 70 Series uses either 30X5.25 or 5.25-20 as a primary bias-ply tire, depending on the wheel setup on the individual car. One size should match the car's actual rims and tire markings.
Start by reading the existing tire size if it is still legible, then confirm the wheel diameter directly. Antique and pre-war cars are especially prone to long-ago changes in wheels, hubs, or restoration choices, so assumptions can lead to expensive mistakes. Once the correct size is established, the decision becomes much simpler: replace like with like and verify condition, fitment, and roadworthiness before driving.
Why is wheel confirmation so important when choosing tires for a 1926 Willys-Knight 70 Series?
Wheel confirmation matters because the 1926 Willys-Knight 70 Series does not rely on a single tire size across all examples in this fitment. It may use 30X5.25 or 5.25-20, and those sizes correspond to different wheel dimensions. Ordering by vehicle name alone can therefore miss the actual setup on a specific car.
A careful measurement saves time and protects the restoration from unnecessary mounting problems. It is worth checking the wheels for matching diameters, inspecting any spare, and comparing old sidewall markings if they remain readable. On a nearly hundred-year-old automobile, small differences in hardware can have a big effect on tire choice, so verification at the wheel is the most dependable starting point.
Restoration & Appearance
Which tire should I choose for a period-style 1926 Willys-Knight 70 Series?
For a period-style 1926 Willys-Knight 70 Series, the right starting point is the car's actual primary bias-ply size, either 30X5.25 or 5.25-20. Staying with the correct vintage size and construction helps preserve the proportions and road-going character expected of a mid-1920s automobile. The key is matching the car's existing wheel setup accurately.
Appearance on a pre-war vehicle is influenced heavily by tire profile and overall visual scale, so even a seemingly close substitute can change the look. Owners aiming for a historically appropriate restoration should compare the current setup against marque references, restoration photos, or other authoritative period sources. That extra step is especially worthwhile when the car has passed through earlier restorations.
Does correct tire fitment matter for a 1926 Willys-Knight 70 Series restoration?
Correct tire fitment matters a great deal on a 1926 Willys-Knight 70 Series because tire size strongly affects stance, wheel appearance, and the overall visual balance of a pre-war car. Using the proper primary bias-ply size, whether 30X5.25 or 5.25-20, helps the finished restoration look coherent rather than improvised.
Fitment also matters beyond appearance. The wrong tire can create mounting issues, alter how the car sits, or introduce clearance concerns that do not suit an older chassis. A restoration-minded owner should verify wheel dimensions, inspect wheel condition, and make sure all tires on the car follow the same sizing plan. Consistency across the set is just as important as choosing a vintage-looking tire.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1926 Willys-Knight 70 Series?
Yes, modifications can affect tire fitment on a 1926 Willys-Knight 70 Series. If the car has replacement wheels, altered hubs, brake updates, suspension work, or body adjustments from an older restoration, the original tire-size assumption may no longer match the hardware on the car. That is especially important here because two primary sizes are associated with this model.
A sensible check includes wheel diameter, wheel condition, and visible clearance around fenders and steering components. It also helps to confirm that all four wheels match before mounting a full set of tires. Even if the car looks stock, pre-war vehicles often carry long-ago changes that are easy to miss until tire installation begins, so physical verification is always worthwhile.
What should I inspect before driving a 1926 Willys-Knight 70 Series on new tires?
Before driving a 1926 Willys-Knight 70 Series on new tires, inspect the wheels for damage, corrosion, cracks, and general structural soundness. The valve hardware, wheel fasteners, and overall mounting condition should also be checked carefully. On an older car, tire installation is only part of road readiness; the supporting wheel hardware matters just as much.
It is also smart to verify inflation, look for adequate clearance at full steering lock, and make sure the suspension and steering do not show obvious looseness. A short test drive followed by another inspection can reveal rubbing, settling, or air loss before a longer outing. Pre-war cars reward careful preparation, especially after fresh tires are mounted for the first time.
How should tires on a collector 1926 Willys-Knight 70 Series be maintained?
Tires on a collector 1926 Willys-Knight 70 Series should be inspected regularly even if the car is driven only occasionally. Look for sidewall cracking, cuts, bulges, irregular wear, and signs of air loss, and keep inflation consistent with the tire's intended use. Low annual mileage does not prevent age and storage conditions from affecting an older vehicle's tires.
Storage habits make a real difference on a pre-war car. Keeping the vehicle away from prolonged sunlight, excess moisture, and ozone-producing equipment can help protect the tire surface over time. It also helps to check the tires before every outing rather than only during annual service. Collector vehicles often sit for long periods, so condition can change between drives without much warning.
