Your expert guide to understanding wheel terminology for automotive, truck, and vintage vehicles
Alloy Wheels
Wheels made from an alloy of aluminum or magnesium. Lighter than steel wheels, they improve handling and fuel efficiency while offering better heat dissipation for braking systems. Available in countless designs for both modern and classic vehicles.
Aftermarket Wheels
Wheels produced by companies other than the original vehicle manufacturer. Often chosen for improved performance, different aesthetics, or custom sizing options.
Backspacing
The distance from the mounting surface of the wheel to the back edge of the wheel. Crucial for proper fitment and clearance with suspension components.
Beadlock
A mechanical device that secures the tire bead to the wheel rim. Used in off-road applications where extremely low tire pressures are needed for maximum traction.
Bolt Pattern
The arrangement of lug holes on a wheel, specified by the number of lugs and the diameter of the circle they form. For example, a 5x114.3 pattern has 5 lugs arranged in a circle with a diameter of 114.3mm.
Cast Wheels
Wheels manufactured by pouring molten metal into a mold. The most common and economical production method for alloy wheels. Generally heavier than forged wheels but more affordable.
Center Bore
The center hole in the wheel that centers it on the hub of the vehicle. A precise fit is important for proper wheel balance and to prevent vibration.
Chrome Wheels
Wheels with a chrome-plated finish for a mirror-like shine. Popular for both modern and vintage applications, though they require special care to maintain their appearance.
Deep Dish
Wheels with an exaggerated distance between the mounting surface and the outer lip, creating a pronounced concave appearance. Popular in custom applications for their distinctive look.
Diameter
The measurement of a wheel from one edge to the opposite edge, passing through the center. Commonly measured in inches (e.g., 15", 17", 20").
Dually Wheels
Specialized wheels designed for dual rear wheel (DRW) trucks. They feature a specific offset and are narrower than single rear wheels to accommodate two wheels side by side on each end of the rear axle.
Finishes
Various treatments applied to wheels for aesthetic and protective purposes. Common finishes include painted, polished, machined, anodized, powder-coated, and chrome-plated.
Flow-Formed Wheels
A manufacturing process that combines casting and forging techniques. The wheel starts as a cast piece, then undergoes a spinning process under heat and pressure to create a stronger, lighter wheel than traditional casting.
Forged Wheels
Wheels created by pressing a solid block of aluminum under extreme pressure to form the wheel shape. This process aligns the metal's grain structure, resulting in wheels that are stronger and lighter than cast wheels.
Hub-Centric
Wheels designed to center on the vehicle's hub rather than on the lug nuts. Hub-centric wheels provide better balance and reduce stress on the lug nuts and studs.
Hub-Centric Rings
Plastic or metal rings that fit between the wheel's center bore and the vehicle's hub to create a hub-centric fit when the wheel's center bore is larger than the hub diameter.
Lip
The outer edge of a wheel. Multi-piece wheels often feature replaceable lips that can be wider or narrower to change the wheel's width and appearance.
Lug Nuts/Bolts
Fasteners that secure the wheel to the vehicle. Available in various styles including acorn, spline, and tuner, with different seat types (conical, spherical, flat) depending on the wheel design.
Machined Finish
A wheel finish where the face is cut with a lathe after painting to expose the bare metal, creating a contrast between the painted and bare metal surfaces.
Magnesium Wheels
Extremely lightweight wheels made from magnesium alloy. Originally used in racing applications, they're less common today due to their higher cost and susceptibility to corrosion.
Multi-Piece Wheels
Wheels constructed from two or three separate pieces (usually center, inner barrel, and outer lip) bolted together. Allows for custom widths, offsets, and mixed finish options.
OEM Wheels
Original Equipment Manufacturer wheels that come standard on vehicles from the factory. Designed specifically for the vehicle's performance characteristics and styling.
Offset
The distance between the wheel's mounting surface and the centerline of the wheel. Measured in millimeters and can be positive (mounting surface toward the outside), zero, or negative (mounting surface toward the inside). Critical for proper fitment.
PCD (Pitch Circle Diameter)
Another term for bolt pattern, measuring the diameter of the circle formed by the center of the lug holes.
Powder Coating
A durable wheel finish applied as a dry powder and then cured with heat to form a protective skin. More durable than traditional paint and available in countless colors and textures.
Replica Wheels
Aftermarket wheels designed to look like OEM or premium brand wheels but typically manufactured at a lower cost. Popular for vintage vehicle restorations where original wheels are unavailable or prohibitively expensive.
Rotary Forged
Another term for flow-formed wheels, referring to the manufacturing process that spins cast wheel blanks under heat and pressure to improve strength and reduce weight.
Spoke
The structural elements that connect the center of the wheel to the rim. Wheel designs vary widely in the number, shape, and arrangement of spokes.
Steelies
Colloquial term for steel wheels. Common as OEM wheels on base model vehicles, winter wheels, and many vintage vehicles. Heavier but generally more durable and less expensive than alloy wheels.
Split-Rim Wheels
Vintage and specialty wheels where the rim is composed of two or more pieces bolted together, allowing for tire mounting without specialized equipment. Common on older trucks and some vintage European sports cars.
Two-Piece Wheels
Wheels constructed from a center section and a rim section bolted together. Allows for custom offsets and widths while offering repair possibilities if one section is damaged.
Three-Piece Wheels
Wheels constructed from a center section and two rim halves (inner and outer) bolted together. Offers the most customization potential in terms of width, offset, and finish combinations.
Valve Stem
The component that allows air to be added to or released from the tire. Modern wheels typically use rubber valve stems, while performance applications may use metal stems for durability at high speeds.
Vintage Wire Wheels
Classic wheel design featuring numerous thin metal spokes radiating from the hub to the rim. Popular on vintage British and European sports cars. Original versions often required specialized maintenance including periodic re-tensioning of spokes.
Width
The measurement from the inside edge to the outside edge of the wheel. Typically measured in inches and crucial for proper tire fitment.
Wheel Spacers
Devices installed between the hub and wheel to increase the distance the wheel sits from the vehicle. Used to create clearance for larger brakes or to adjust the wheel's stance for aesthetic purposes.
Wheel Weight
Small weights attached to the wheel to balance it and prevent vibration. Available in clip-on styles for steel wheels and adhesive styles for alloy wheels with finished lips.
How do I know which wheels will fit my vehicle?
To determine proper wheel fitment, you need to know your vehicle's bolt pattern, center bore, offset, and clearance requirements. Most wheel retailers offer vehicle-specific lookups to ensure compatibility. For modified vehicles or custom applications, additional measurements may be necessary to ensure proper clearance with suspension components and body panels.
What's the difference between cast and forged wheels?
Cast wheels are created by pouring molten metal into a mold, making them more affordable but generally heavier. Forged wheels are made by pressing solid metal under extreme pressure, resulting in a stronger, lighter wheel with a more refined grain structure. Forged wheels typically offer better performance but at a higher price point.
Can I use wheels with a different offset than my OEM wheels?
While it's possible to use wheels with different offsets, changes in offset affect the wheel's position relative to the suspension and body. Decreasing the offset (more negative) pushes the wheel outward, which may improve stability but can cause rubbing against fenders or suspension components. Increasing the offset (more positive) pulls the wheel inward, which may cause clearance issues with suspension components. A general rule is to stay within 5mm of your OEM offset unless other modifications are made.
What are the best wheels for a vintage or classic vehicle?
For vintage vehicles, period-correct wheel styles maintain authenticity while modern reproductions offer improved manufacturing quality. Options range from exact replicas of original equipment to period-inspired designs with modern sizing. Many vintage vehicle owners choose wheels that maintain the original look but in slightly larger diameters to accommodate modern tire options with better performance characteristics.
How do wheel materials affect performance?
Wheel materials significantly impact performance through weight, strength, and heat dissipation properties. Lighter wheels reduce unsprung weight, improving acceleration, braking, and handling. Aluminum alloy wheels offer a good balance of weight reduction and strength while effectively dissipating brake heat. Magnesium alloy wheels are even lighter but more expensive and prone to corrosion. Steel wheels are heavier but extremely durable and cost-effective, making them popular for winter use and off-road applications where impacts are likely.
