Bead

The tire bead is the reinforced inner edge of a tire that sits against the wheel. It helps hold the tire in position and creates the seal needed to retain air in a tubeless tire.

What a tire bead means

The bead contains strong bundles of wire surrounded by rubber. When the tire is mounted and inflated, these bundles press firmly against the wheel’s bead seat. The bead does not stretch like the sidewall; it must remain dimensionally stable so the tire stays centred on the wheel.

Why the bead matters

A properly seated bead supports an even seal and smooth rotation. Dirt, corrosion, mounting damage or an incorrect wheel-and-tire combination can prevent the bead from seating correctly. Possible symptoms include a slow air leak, vibration or a visible section of the tire that does not sit evenly around the rim.

Practical example

If a newly installed tire loses pressure but has no puncture, a technician may inspect the valve stem and the bead area. Cleaning corrosion from the wheel and reseating the tire may restore the seal, provided the tire bead itself is not damaged.

Related terms

Sidewall, bead seat, wheel diameter and tire pressure.