Definition
The central structural part of an aircraft wheel that mounts onto the axle and carries the tire. The hub houses the wheel bearings, provides the mounting surface for the brake disc or drum, and forms the rim onto which the tire is seated.
Plain English
The metal centerpiece of the wheel. It slides onto the axle, holds the bearings that let the wheel spin, supports the tire, and is where the brake parts attach.
Context Anchor
Seen during landing gear, tire, brake, and preflight inspection discussions, especially when checking the wheel area for damage, looseness, or signs of overheating.
Derivation
‘Hub’ is an old English word originally meaning the solid central block of a cart or wagon wheel — the part the spokes radiated out from. The aviation use carries the same idea: the structural center of the wheel that everything else attaches to.
Why Pilots Care
Worn or damaged hubs allow bearing play that produces vibration, tire wear, or wheel lockup on takeoff and landing.
Intuition Check
Do not think of wheel hubs as the tires or the decorative center covers seen on some cars. On an airplane, the hub is a structural part of the wheel assembly that helps carry the airplane’s weight and landing loads.
Example Sentence 1
During preflight, the pilot inspected the wheel hubs for grease leaks and signs of overheating.
Example Sentence 2
After a hard landing the mechanic removed the wheel to inspect the hubs for cracks around the bearing races.