One of the most challenging aspects of selecting whitewall tires is navigating the various sizing systems used throughout automotive history. Whether you're restoring a classic to exact factory specifications, upgrading a vintage vehicle with modern tire technology, or adding whitewalls to a contemporary ride, understanding proper sizing is essential for both performance and appearance.
This comprehensive guide will help you decode tire sizing terminology, find appropriate options for your specific vehicle, and make informed decisions when selecting whitewall tires.
Understanding Whitewall Tire Sizing Systems
Throughout automotive history, several different tire sizing systems have been used, with terminology evolving alongside tire technology. For whitewall applications, three primary sizing systems are relevant:
Vintage Numeric Sizing (Pre-1960s)
Early automotive tires used a straightforward numeric system that directly referenced the physical dimensions of the tire. These sizes are commonly found on vehicles from the 1920s through the 1950s.
Example: 6.00-16
- 6.00 = Nominal width in inches
- 16 = Wheel diameter in inches
This system was intuitive but provided limited information about the tire's complete specifications. As tire technology advanced, more detailed sizing systems became necessary.
Alpha-Numeric Sizing (1960s-1970s)
This transitional sizing system appeared during the 1960s and remained common through the 1970s. It combines letters and numbers to convey more specific tire characteristics.
Example: G78-15
- G = Width code (alphanumeric representation of width)
- 78 = Aspect ratio (height as percentage of width)
- 15 = Wheel diameter in inches
The alpha-numeric system provided more standardization during a period of rapid advancement in tire technology, including the transition from bias-ply to radial construction. Many whitewall tires for classic vehicles from this era use this sizing convention.
Modern Metric Sizing (1970s-Present)
Today's standard tire sizing system uses metric measurements and provides more detailed information about tire dimensions and construction.
Example: P215/75R15
- P = Passenger vehicle designation (other options include LT for light truck)
- 215 = Section width in millimeters
- 75 = Aspect ratio (height as percentage of width)
- R = Radial construction (B would indicate bias-ply)
- 15 = Wheel diameter in inches
Modern whitewall tires typically use this sizing system, though reproduction tires for classic vehicles may be labeled with both contemporary metric sizing and the original vintage or alpha-numeric designation for reference.
Important Note About Bias-Ply vs. Radial Construction:
When selecting whitewall tires, pay particular attention to construction type. Bias-ply tires (original for pre-1970s vehicles) and radial tires have different handling characteristics and load-carrying capabilities. The sizing may appear similar, but these construction differences significantly impact performance and driving experience.
Whitewall Tire Size Conversion Chart
Finding modern equivalents for vintage tire sizes can be challenging. This conversion chart provides general approximations between common vintage sizes and their modern metric equivalents. Always consult with a tire professional for your specific application, as vehicle weight, wheel width, and other factors may influence the optimal choice.
| Vintage Size | Alpha-Numeric Size | Modern Metric Equivalent | Common Applications |
|---|---|---|---|
| 5.00-15 | — | P165/80R15 | Early European sports cars, some 1940s American cars |
| 5.60-15 | — | P175/80R15 | 1950s European sedans, some compact American cars |
| 6.00-16 | — | P185/85R16 | 1930s-1950s American sedans, light trucks |
| 6.50-16 | — | P195/85R16 | 1940s-1950s larger American sedans |
| 7.10-15 | E78-15 | P205/75R15 | 1950s-1960s mid-size American cars |
| 7.60-15 | F78-15 | P215/75R15 | 1950s-1960s full-size American cars |
| 8.00-15 | G78-15 | P225/75R15 | 1950s-1960s luxury American cars |
| 8.50-14 | H78-14 | P235/75R14 | 1960s larger American cars, some luxury models |
| — | F70-14 | P215/70R14 | 1960s-1970s mid-size American cars |
| — | G70-15 | P225/70R15 | 1960s-1970s full-size American cars |
This conversion chart provides general guidelines for size equivalency. Always verify clearance, load rating, and overall diameter for your specific vehicle. When in doubt, consult with whitewall tire specialists before making a purchase decision.
Finding the Right Whitewall Tire Size for Your Vehicle
Selecting the appropriate whitewall tire size involves considerations beyond simple numeric conversions. Follow these steps to determine the optimal size for your specific application:
Step 1: Research Original Equipment
For classic car restorations, identifying the original factory-installed tire size provides the ideal starting point:
- Check the vehicle's owner's manual or factory documentation
- Look for a tire specification sticker in the glove box, door jamb, or trunk
- Consult marque-specific restoration guides or enthusiast communities
- Reference factory parts catalogs or service documentation
- Examine period photographs or advertisements showing your specific model
Step 2: Consider Wheel Specifications
Tire fitment must align with your wheel's dimensions and structural capabilities:
- Measure wheel diameter (in inches) from bead seat to opposite bead seat
- Measure wheel width (in inches) from inside of one bead flange to the other
- Verify your wheel width can accommodate the tire size you're considering
- For older wheels, ensure they can handle modern tire pressure requirements
- Consider whether original wheels or modern replacements are being used
Step 3: Evaluate Overall Diameter
Maintaining proper overall diameter is critical for accurate speedometer operation, proper ground clearance, and correct gear ratios:
- Calculate the overall diameter of your original or desired tire size
- Compare this with potential replacement options to ensure minimal diameter variation (ideally less than 3%)
- Consider how diameter changes might affect vehicle stance, fender clearance, and driving characteristics
- Factor in that bias-ply and radial tires of the same nominal size may have slightly different actual dimensions
Step 4: Balance Authenticity with Practicality
Determine your priorities between strict historical authenticity and modern performance benefits:
- For concours restorations: Prioritize exact original tire specifications and construction
- For regularly-driven classics: Consider modern radial construction with period-correct appearance
- For modified or custom vehicles: Select sizes that complement your desired stance and performance goals
- For modern vehicles with whitewalls: Choose narrower whitewall styles in contemporary sizing
Period-Correct Whitewall Sizing By Era
Different automotive eras featured distinctive whitewall tire sizes and styles. This guide helps identify period-correct options based on your vehicle's age:
1930s - Early 1940s
Common Sizes: 4.75-19, 5.00-17, 5.50-17, 6.00-16, 6.50-16, 7.00-16
Whitewall Width: 3-4 inches (wide whitewalls)
Construction: Bias-ply
Notes: Early whitewalls featured wide bands of natural white rubber. Tires of this era had tall, narrow profiles compared to modern designs. Premium vehicles often featured larger wheel diameters with proportionally sized whitewalls.
Late 1940s - Early 1950s
Common Sizes: 6.00-16, 6.70-15, 7.10-15, 7.60-15, 8.00-15, 8.20-15
Whitewall Width: 2.5-3.5 inches (medium-wide whitewalls)
Construction: Bias-ply
Notes: The post-war period saw a transition toward 15-inch wheel diameters for many American vehicles. White wall width remained substantial but began a gradual narrowing trend as automotive styling evolved toward more modern aesthetics.
Mid-1950s - Early 1960s
Common Sizes: 7.10-15, 7.60-15, 8.00-15, 6.50-14, 7.00-14, 7.50-14, 8.00-14
Whitewall Width: 1.5-2.5 inches (medium whitewalls)
Construction: Bias-ply
Notes: The trend toward 14-inch wheels gained momentum during this period, particularly for non-luxury models. White wall width continued to narrow, complementing the lower, wider styling trends of American automobiles during this era.
Mid-1960s - Early 1970s
Common Sizes: E78-14, F78-14, G78-14, F78-15, G78-15, H78-15, F70-14, G70-14, G70-15
Whitewall Width: 0.75-1.5 inches (narrow whitewalls)
Construction: Bias-ply transitioning to radial
Notes: The alpha-numeric sizing system emerged during this period. The "70" series sizes indicate wider tires with lower profiles, often associated with performance models. White wall width narrowed significantly, reflecting modernized automotive styling.
Mid-1970s - 1980s
Common Sizes: P195/75R14, P205/75R14, P215/75R15, P225/75R15, P205/70R14, P215/70R15
Whitewall Width: 0.3-0.75 inch (pinstripe whitewalls)
Construction: Radial
Notes: Modern metric sizing became standard during this period. Radial construction was widely adopted across the industry. White walls narrowed to thin pinstripes before gradually disappearing from most production vehicles by the late 1980s.
Whitewall Tire Sizing for Custom Applications
For custom vehicles or non-traditional applications, selecting the appropriate whitewall tire size involves additional considerations beyond period correctness:
Custom Rod and Lowrider Applications
These distinctive styles often feature specific whitewall and tire combinations:
- Traditional Hot Rods: Often use wide whitewalls in sizes like 5.60-15, 6.00-16, or 7.00-16 on front wheels with larger rear tires
- Custom Lead Sleds: Typically feature wide whitewalls in larger diameters, such as 8.00-15 or P215/75R15 with wide (3+ inch) whites
- Lowriders: Commonly use 5.20-14 tires (or modern P175/75R14 equivalents) with 1.5-2.5 inch whitewalls, though size preferences vary by region and style
- Contemporary Customs: May combine larger diameter wheels (17-20 inch) with specialized narrow whitewall tires for a modernized classic look
Larger Diameter Modern Wheels
For vehicles with upgraded modern wheels seeking whitewall aesthetics:
- Consider whitewall tire options in contemporary sizing (limited but available)
- Explore portawall inserts for applications where dedicated whitewall tires aren't manufactured
- Select the narrowest whitewall width option for the most cohesive appearance with larger wheels
- Ensure proper load rating and speed rating for your specific vehicle weight and performance needs
- Verify that overall diameter maintains proper clearance and speedometer calibration
Vintage-Inspired Modern Vehicles
For contemporary vehicles seeking classic whitewall styling:
- Modern retro-inspired vehicles (PT Cruiser, Mini Cooper, Fiat 500, etc.) typically use 15-17 inch wheels
- Consider whitewall options in P195/65R15, P205/55R16, or similar sizes depending on wheel fitment
- Select narrow whitewall styles (0.5-1 inch) for more harmonious integration with modern designs
- Ensure any whitewall tire meets or exceeds the vehicle manufacturer's specifications for load and speed rating
- Verify compatibility with modern electronic systems (TPMS, ABS, stability control)
Understanding Load and Speed Ratings
Beyond size considerations, proper load and speed ratings are crucial for safe operation with whitewall tires:
Important Safety Considerations
Never compromise on load rating or speed rating to achieve a specific whitewall appearance. Safety should always be the primary consideration when selecting tires, regardless of styling preferences. Under-specified tires can lead to dangerous failures, particularly during emergency maneuvers or highway driving.
Frequently Asked Questions About Whitewall Tire Sizing
How do I determine the correct whitewall size for my classic car?
Start by researching your vehicle's original specifications through factory documentation, owner's manuals, or marque-specific restoration guides. For most vehicles manufactured before 1970, bias-ply whitewalls were standard equipment. The appropriate whitewall width varies by era: 3-4 inches for 1930s-1940s, 2-3 inches for early-mid 1950s, 1-2 inches for late 1950s-1960s, and under 1 inch for 1970s models. When selecting modern reproductions, ensure the overall diameter, load rating, and construction type align with your vehicle's requirements.
Can I use modern radial whitewall tires on my vintage car?
Yes, modern radial whitewall tires are available for many vintage applications. These provide improved handling, longer tread life, and better fuel efficiency compared to original bias-ply designs, while maintaining period-correct appearance. When converting from bias-ply to radial, ensure the overall diameter remains within 3% of original specifications to maintain proper speedometer accuracy and mechanical clearances. Some purists prefer bias-ply tires for concours restoration purposes, but radials offer practical advantages for vehicles driven regularly.
How do the old numeric tire sizes translate to modern measurements?
Vintage numeric sizes (e.g., 6.00-16) can be approximated in modern metric format using conversion charts. The first number (6.00) roughly indicates section width in inches, while the second number (16) represents wheel diameter in inches. A 6.00-16 tire would convert to approximately P185/85R16 in modern sizing. However, exact equivalencies vary by manufacturer, and factors like tread design and construction type influence actual dimensions. For precise fitment, consult specialized tire resources or professionals familiar with vintage applications rather than relying solely on general conversion charts.
Are whitewall tires available for larger modern wheels?
White wall tire options become increasingly limited as wheel diameters exceed 17 inches. For 18-22 inch wheels, dedicated whitewall tires are rare, though some specialty manufacturers offer custom whitewall options in limited sizes by special order. Portawalls (removable white rubber inserts) provide an alternative for larger wheels where dedicated whitewall tires aren't manufactured. These inserts create the appearance of whitewalls while allowing the use of standard tires in modern performance sizes. For the most harmonious appearance on larger wheels, narrower whitewall widths (pinstripes) are typically recommended.
How does tire size affect the appearance of whitewalls?
Tire profile (aspect ratio) significantly influences how whitewalls appear on a vehicle. Lower profile tires (e.g., 60 or 55 series) display less sidewall area, making whitewalls appear proportionally larger and more prominent. Higher profile tires (e.g., 75 or 85 series) show more sidewall, allowing wider whitewalls to appear balanced rather than overwhelming. Additionally, overall tire diameter affects stance and wheel well spacing. For aesthetic harmony, consider how the whitewall width relates to your vehicle's fender lines, body style, and overall proportions rather than focusing solely on numeric specifications.