In 1973, Honda was still a young but fast-rising name in the U.S. market, building small, efficient cars that stood apart from Detroit norms. The 1973 Honda lineup at this level centers on the compact 600 and the early Civic, two models that helped define Honda’s reputation for practical engineering and smart packaging. Tire choice across 1973 Honda vehicles varies by model rather than carrying one universal size, and each model pairs an era-correct bias-ply option with a radial alternative. That means the first thing to confirm is whether you have a 600 or a Civic, then decide whether your priority is original-style appearance or more modern radial road manners.
Which Tire Size Is Right for Your 1973 Honda
Four tire sizes are used across 1973 Honda vehicles, and they vary by model rather than fitting the full range universally. The main decision is first identifying whether you have a 600 or a Civic, then choosing between an original-style bias-ply size and a radial size for that model. Understanding that distinction before choosing a product saves time and helps match the tire to the car and the way it will be driven.
Year(s): 1973|Fit(s): 600|Construction: Radial|Rim: 10 in
145R10 is a euro-metric radial size with a 145-millimeter section width and a 10-inch rim diameter; in this format, the missing aspect ratio is conventionally treated as an 80-series profile. This size is specific to the 1973 Honda 600 and is available from Firestone, Kings, Camac, and Dunlop in Blackwall form, with speed rating details varying by product; Dunlop carries an S rating, which is rated to 112 mph. It suits an owner who wants radial construction for more familiar road behavior while staying with the correct 10-inch wheel diameter for the 600.
Year(s): 1973|Fit(s): 600|Construction: Bias Ply|Rim: 10-in rim
5.20-10 is a numeric bias-ply size in which 5.20 refers to the nominal section width and 10 is the rim diameter in inches. This size is specific to the 1973 Honda 600 and represents the traditional bias-ply fitment style associated with small cars of the period. It is the natural choice for a restoration-focused owner who wants the look and construction type most in keeping with early-1970s small-car presentation.
Year(s): 1973|Fit(s): Civic|Construction: Radial|Rim: 12-in rim
155R12 is a euro-metric radial size with a 155-millimeter section width and a 12-inch rim diameter; in this format, the missing aspect ratio is conventionally understood as an 80-series profile. This size is specific to the 1973 Honda Civic and represents the radial option for Honda’s early subcompact platform. It makes sense for a Civic owner who wants a radial tire matched to the original 12-inch wheel diameter and a driving feel closer to what modern motorists expect from a compact car.
Year(s): 1973|Fit(s): Civic|Construction: Bias Ply|Rim: 12-in rim
6.00-12 is a numeric bias-ply size in which 6.00 denotes the nominal section width and 12 identifies the rim diameter in inches. This size is specific to the 1973 Honda Civic rather than the 600, so it is not a year-wide Honda fitment. It is best suited to owners seeking a period-correct bias-ply presentation for an early Civic, especially when restoration character matters more than radial-style road feel.
Two Honda models are covered for 1973 at this level: the 600 and the Civic. Tire size changes by model, so identifying which Honda you have matters before choosing a size, since the 600 uses 10-inch tires and the Civic uses 12-inch tires. Select a model below to narrow the fitment history and see products matched to that specific Honda.
1973 Honda 600
The Honda 600 was one of the small-displacement economy cars that introduced many American buyers to the brand’s engineering philosophy. It uses 10-inch tires, and its tire choices split between a traditional bias-ply option and a radial option depending on whether the goal is restoration character or more modern road manners.
The first-generation Civic arrived as a practical subcompact that would become one of Honda’s defining nameplates in the U.S. It mounts on 12-inch tires, with one radial size and one bias-ply size available depending on whether you favor later-style drivability or an earlier factory-era appearance.
Four products are available across one tire size for 1973 Honda vehicles. The 145R10 radial is offered in four Firestone, Kings, Camac, and Dunlop versions, all with Blackwall styling. Confirm your model and size first, since 600 and Civic fitments are different and speed ratings can vary within the same size.
These FAQs focus on how 1973 Honda tire fitment changes between the 600 and Civic, how bias-ply and radial choices differ for each model, and what to check for storage, setup, and road use on a light vintage Honda.
Size Basics & Fitment
What tire sizes fit 1973 Honda vehicles?
1973 Honda vehicles use four model-specific tire sizes. The Honda 600 uses either 145R10 radial tires or 5.20-10 bias-ply tires, both for 10-inch wheels. The Honda Civic uses either 155R12 radial tires or 6.00-12 bias-ply tires, both for 12-inch wheels. Those pairings mean there is no single tire size that fits every 1973 Honda model.
The practical takeaway is simple: confirm the model before you focus on brand or sidewall style. A 600 owner needs to stay within the 10-inch fitment family, while a Civic owner needs the 12-inch family. After that, the choice usually becomes one of construction type, with bias-ply favored for period presentation and radial construction favored by many owners who drive their cars more regularly.
What does 145R10 mean on a 1973 Honda tire?
On a 1973 Honda, 145R10 is a euro-metric radial size. The 145 indicates nominal section width in millimeters, the R identifies radial construction, and the 10 is the wheel diameter in inches. In this older metric style, the aspect ratio is not written into the size code, but it is conventionally treated as an 80-series profile.
That makes 145R10 the radial-format choice for the Honda 600 rather than a generic Honda size. It keeps the correct 10-inch wheel diameter while using a later-style sizing system that became familiar on compact imports. If you are comparing products within 145R10, check the sidewall markings on the exact tire because speed ratings can differ even when the nominal size stays the same.
What does 5.20-10 or 6.00-12 mean on a 1973 Honda tire?
On a 1973 Honda, 5.20-10 and 6.00-12 are numeric bias-ply tire sizes. The first number is the nominal section width in inches, and the second number after the dash is the wheel diameter in inches. That means 5.20-10 is the bias-ply fitment family for the Honda 600 on 10-inch wheels, while 6.00-12 is the bias-ply fitment family for the Civic on 12-inch wheels.
These sizes matter because they reflect the older sizing language used before modern metric radial fitments became dominant. If your goal is a restoration that looks right for an early-1970s economy car, numeric bias-ply sizing is usually the more era-appropriate direction. If your priority is a more modern driving feel, compare the corresponding radial size for your specific Honda model rather than crossing between 600 and Civic sizes.
Buying the Right Tire
Should I choose the bias-ply size or the radial size for my 1973 Honda?
For a 1973 Honda, the choice depends on your model and your goal. The Honda 600 pairs 5.20-10 in bias-ply form with 145R10 in radial form, while the Civic pairs 6.00-12 in bias-ply form with 155R12 in radial form. Bias-ply tires are the more traditional period-style construction, while radial tires are the later construction type that many drivers associate with more familiar day-to-day road manners.
Owners restoring a car for a factory-era look often stay with the numeric bias-ply size that matches the period character of the vehicle. Owners who expect more frequent casual driving often lean toward the radial counterpart for their model. The key is not to compare across the whole 1973 Honda range, but to choose between the two construction types within the correct 600 or Civic fitment family.
What sidewall styles are available for 1973 Honda tires?
Blackwall sidewalls are available in 145R10 for the 1973 Honda 600. That look fits the clean, simple appearance expected on many small imported economy cars of the early 1970s, especially when the goal is an understated factory-style presentation rather than a more decorative sidewall treatment.
Sidewall style matters visually even when the size is correct, because it changes how authentic the car looks at a glance. For a modest early Honda, Blackwall tires are usually the safest visual choice when you want the car to retain its original character. If you are preparing a show-focused restoration, compare the sidewall style on the exact tire with period photos and model-specific enthusiast references before making the final call.
What brands make tires for 1973 Honda 600 vehicles?
The 145R10 radial size for the 1973 Honda 600 is available from Firestone, Kings, Camac, and Dunlop. All of those options share Blackwall styling, while individual details such as weight, load information, and speed rating markings can differ from one tire to another within the same size.
Brand choice becomes more important after you have already confirmed that your car is a 600 and that you want the 145R10 radial fitment family. At that point, compare the exact sidewall markings and construction details that matter to your project. A driver-focused car may prioritize a familiar radial brand character, while a display-oriented car may put more weight on overall visual presentation and period flavor.
Fitting & Setup
Do 1973 Honda tires require inner tubes?
Tube requirements for 1973 Honda tires depend on the exact tire and wheel combination rather than on the year and make alone. The available 145R10 radial products for the Honda 600 are not marked in a way that establishes one universal tube requirement across the size, so that decision should be confirmed from the tire’s own sidewall marking and from the wheel condition and design.
That matters because many vintage wheels and reproduction tires can be physically compatible in size but differ in whether they are intended to run tube-type or tubeless. Before mounting, check the actual wheel for bead-seat condition, corrosion, and any original design features that influence sealing. If you are working with a restored early Honda wheel, this is a good point to involve a shop familiar with vintage small-diameter wheels.
Can the original 1973 Honda wheels be used with both tire sizes for each model?
Yes, within each model’s own fitment family, both tire sizes share the same wheel diameter. The Honda 600 uses 10-inch wheels whether you choose 145R10 radial or 5.20-10 bias-ply, and the Civic uses 12-inch wheels whether you choose 155R12 radial or 6.00-12 bias-ply. The wheel diameter does not interchange between the 600 and Civic families.
That means an original 600 wheel can stay in service when moving between the 600’s bias-ply and radial options, and the same idea applies within the Civic’s 12-inch choices. Even so, wheel diameter alone is not the whole fitting story. Confirm the actual wheel condition and the tire manufacturer’s approved wheel specifications before mounting, especially on older small-diameter wheels that may have seen decades of use or previous repairs.
Maintenance, Storage & Longevity
How should I store a 1973 Honda when the tires are fitted?
A 1973 Honda should be stored in a cool, dry, dark space away from direct sunlight, electric motors, battery chargers, welders, and other ozone-producing equipment that can accelerate rubber aging. Keep the tires clean, maintain proper inflation, and move the car occasionally so it does not sit on one contact patch for months at a time. Bias-ply tires are generally more prone to temporary flat-spotting during long static storage than radial tires.
If the car will sit for an extended season, many owners either roll it periodically or place it on stands that relieve some load while still supporting the suspension correctly. That is especially helpful on light vintage compacts with small-diameter tires. A simple storage routine preserves sidewalls, helps the car feel smoother when returned to service, and reduces the chance of finding cracks or pressure loss right before the next drive.
How long do tires on a 1973 Honda typically last?
For a 1973 Honda, tire life is usually judged more by age and condition than by miles traveled. A sensible collector-car rule is to begin evaluating tires closely once they are around five to seven years old and to give serious replacement consideration at roughly ten years, even if tread depth still looks acceptable. The DOT date code on the tire is the best starting point for determining age.
That guideline matters because many vintage Hondas see light use, so the rubber can age out long before the tread wears out. Sidewall cracking, hardening, vibration, or repeated air loss are stronger warnings than odometer mileage on a collector vehicle. If the car has an older spare, inspect that tire as carefully as the four on the ground, since it may be the oldest tire on the car and still expected to work in an emergency.
How often should tires on a 1973 Honda be inspected?
Tires on a 1973 Honda should be inspected before every drive and again before any longer outing. Look for visible cracking, cuts, bulges, irregular tread wear, and signs of pressure loss, and check that each tire is holding inflation consistently. If your chosen setup uses tubes, valve stems and the condition of the tube-related hardware deserve the same attention as the tread and sidewall.
Frequent inspection is especially important on older small cars because they may spend long stretches parked and then return suddenly to active use. Catching a weathered sidewall or a slowly leaking valve stem in the garage is far better than discovering it on the road. Make tire inspection part of a broader pre-drive check that also includes brakes, wheel bearings, steering response, and the condition of the spare.
Restoration & Authenticity
What tires were originally fitted to the 1973 Honda 600?
The 1973 Honda 600 belongs to an era when compact cars could be found with either traditional bias-ply fitments or radial replacements depending on market and service history, but bias-ply construction remained the more period-typical starting point for originality-minded restoration work. For the 600, the two fitment families are 5.20-10 in bias-ply form and 145R10 in radial form, both for 10-inch wheels. Original-equipment branding should be confirmed through model-specific references rather than assumed.
If your goal is authenticity, start by matching the construction type and size family that best suits the way the car would have appeared in its original market and ownership context. Tire sidewall appearance also affects the impression of correctness on a very small economy car. Marque clubs, period brochures, and unrestored survivor cars are the right places to verify market-specific details before committing to a concours-level restoration.
Does correct tire fitment matter for showing a 1973 Honda?
Yes, correct tire fitment can matter a great deal when showing a 1973 Honda. Judges and knowledgeable enthusiasts often notice whether the tire size, construction type, and sidewall appearance suit the era and the model. On an originality-focused Honda 600 or early Civic, a modern radial may look out of character if the event emphasizes factory-correct presentation, while an incorrect diameter family would stand out immediately.
The standard is not identical at every event, which is why show preparation should match the type of judging you expect. A local casual display may be flexible, while marque-specific or concours judging may be much stricter about construction and appearance. Before finalizing a set, compare your chosen tire with period images and ask the relevant club or event organizers what they consider acceptable for your exact 1973 Honda model.
What tires were originally fitted to the 1973 Honda Civic?
The 1973 Honda Civic sits at the beginning of a period when small imported cars increasingly moved toward radial tire usage, but bias-ply construction was still part of the period landscape and remains relevant for restoration choices today. The Civic’s fitment family here is either 6.00-12 in bias-ply form or 155R12 in radial form, both using 12-inch wheels. That makes the original-style question as much about construction type and presentation as it is about raw size.
For a show-oriented Civic, the best approach is to decide first whether the car is being restored to a strict factory-era appearance or to a sympathetic vintage-driver standard. Bias-ply construction usually aligns more naturally with period authenticity, while radial construction can reflect later service replacement practice. Period advertising, owner manuals, and Civic-specific enthusiast communities are the best sources for settling market-by-market originality questions.
Safety & Road Use
Are 1973 Honda tires safe for highway driving?
1973 Honda tires can be suitable for highway use when they are in good condition, properly mounted, correctly inflated, and matched to the car’s actual size requirement. Within the available 145R10 radial options for the Honda 600, one tire carries an S speed rating, which corresponds to 112 mph. That ceiling is well beyond normal U.S. highway speeds, though the real-world limits of a 1973 Honda usually come more from the car’s age, braking system, steering, suspension, and overall mechanical condition than from the tire alone.
The important distinction is between being technically capable of highway travel and being prepared for it as a vintage car. A carefully maintained Honda 600 or early Civic on fresh tires is very different from a long-stored car on aged rubber. Before regular highway use, treat the tires as one part of a complete roadworthiness check and make sure the whole car is ready for sustained speed, heat, and emergency maneuvers.
What inflation pressure should I use for 1973 Honda tires?
Inflation pressure for 1973 Honda tires should begin with the factory recommendation for the exact model and tire size, then be checked against the tire manufacturer’s own markings for the product you choose. The available 145R10 radial fitment includes examples with a maximum load of 694 pounds, with one tire marked at 30 psi and another carrying the same load figure without the pressure paired in the size details. Pressure should never be transferred casually from one size family to another.
That means a Honda 600 on 145R10 should be set up according to 600-specific guidance, while a Civic on 155R12 or 6.00-12 should be treated separately. Maximum pressure on the tire is not automatically the correct operating pressure for the car. A good procedure is to verify the owner’s manual recommendation, confirm the tire’s own sidewall limits, and then check wear and handling over time rather than inflating by guesswork.
What should I check before taking a 1973 Honda on a longer drive?
Before taking a 1973 Honda on a longer drive, inspect each tire for sidewall cracking, cuts, bulges, uneven wear, and proper inflation, and make sure the spare is usable and inflated as well. If your setup uses tubes, pay extra attention to valve stems and any signs of slow leakage. Also check wheel fasteners, brake function, steering feel, and whether the car tracks straight without vibration.
Longer drives put more heat and sustained load into the tires than short neighborhood trips, so small issues become more important. A lightly used vintage Honda may seem fine around town while still hiding an aging spare, a weak valve stem, or a tire that has hardened with age. Doing a slow, methodical pre-trip inspection helps protect the tire investment and gives the car a much better chance of completing the outing comfortably and safely.
