As a core component of a vehicle's running gear, the wheel undertakes crucial functions such as supporting the entire vehicle's weight, cushioning road impacts, and transmitting driving and braking forces. Its structure mainly consists of rims, spokes, hubs, and tires. Although rims, spokes, and hubs sound similar, their functions and structures differ significantly. Below, we will provide a detailed analysis of these differences.

Rims, also known as wheel rims, are the base components for installing and securing tires. They work in tandem with spokes to bear the wheel's load and efficiently dissipate the heat generated by the tires. Common rims are often integrated with spokes. Depending on the manufacturing materials, they are colloquially referred to as "steel rims" (steel rims, which are cost-effective and high-strength, commonly used in commercial vehicles) and "aluminum rims" (aluminum alloy rims, which are lightweight and offer excellent heat dissipation, widely applied in passenger cars). For instance, due to their high load-bearing requirements, trucks typically use steel rims, while passenger cars favor aluminum alloy rims to enhance handling and fuel efficiency.

Spokes serve as the bridge connecting rims and hubs, playing a pivotal role in supporting and transmitting forces within the wheel structure. Based on their structural forms, wheels can be categorized into two types: disk-spoke type and wire-spoke type:

In terms of design, vehicles that frequently travel at high speeds usually adopt multi-spoke designs to enhance support rigidity and reduce deformation. On the other hand, vehicles used for short-distance racing often opt for fewer spokes to achieve extreme lightness, presenting a unique mechanical aesthetic. Additionally, the connection methods between spokes and rims can be divided into integral type (one-piece molding, high strength), permanent connection type (welding or riveting), and detachable type (bolt connection, facilitating maintenance and replacement).

Hubs, commonly known as "hubcaps," are the connecting hubs between wheels and axles. They secure the rims and axles with bolts or pins and provide central support for the wheels. The functional difference between hubs and rims lies in that hubs focus on connecting the axle and wheel, while rims are responsible for tire installation. Modern hubs often adopt the hub unit design, integrating components such as bearings and seals. This not only simplifies the assembly process but also reduces maintenance costs and improves driving stability. For example, high-end vehicles are often equipped with intelligent hub units integrated with ABS sensors, which can monitor wheel speeds in real-time to ensure driving safety.