Definition
The reinforced inner edge of an aircraft tire that seats against the wheel rim and locks the tire onto the wheel. The bead is built around bundles of high-tensile steel wires encased in rubber, giving it the strength to hold the tire in place against inflation pressure, cornering loads, and the forces of takeoff and landing.
Plain English
The strong, wire-reinforced inner edge of the tire that grips the wheel rim and keeps the tire securely attached to the wheel.
Context Anchor
Seen during aircraft tire inspection, tire mounting, and wheel maintenance.
Derivation
From Old English 'beag', meaning a ring or circular band. The name fits because the bead forms a continuous ring around the inside edge of the tire.
Why Pilots Care
A damaged or improperly seated bead can allow a tire to slip on the rim or lose pressure, both of which are serious problems during takeoff and landing. Mechanics inspect beads carefully during tire changes and overhauls.
Analogy
Think of the bead like the tight edge of a lid that locks onto a container. If that edge is bent or damaged, the lid will not hold correctly.
Intuition Check
Do not think of a bead here as a small loose ball or decoration. On an aircraft tire, the bead is a built-in reinforced edge that holds the tire on the wheel.
Example Sentence 1
During the tire change, the mechanic inspected each bead for cuts or distortion before mounting the new tire on the wheel.
Example Sentence 2
A damaged bead can cause the tire to separate from the rim during takeoff or landing.