Wheel diameter for HTS classification is typically measured as the nominal rim diameter (the diameter of the wheel at the bead seat, not including the tire). Under 871690, separate 10-digit lines apply to wheels in the 30–42 cm range (8716905035), aluminum wheels in the 57–63 cm range (8716905046), and steel wheels in the same 57–63 cm range (8716905047), with a residual line for other sizes (8716905048). Importers should obtain manufacturer specifications confirming nominal rim diameter and material to select the correct line.

Not necessarily. Parts that are identifiable as suitable for use solely or principally with a specific vehicle type are classified with that vehicle's heading. A component that is genuinely common to trailers and, say, passenger cars would require analysis under GRI 3 to determine the heading that gives the most specific description. In practice, CBP looks at design intent, marketing, and technical specifications; a part engineered and sold specifically for trailer axles would typically remain in 871690 even if it could physically fit another application.