SINGLE PLY CASING
One layer of nylon wrapped from bead to bead, a single ply conforms well to the terrain and is lighter weight.
DUAL PLY CASING
Two pieces of casing are used from bead to bead which provides additional protection in Downhill applications.
A sturdy material is needed to hold the tyre against the rim when inflated. Wire is used to ensure the bead will not expand, but wire is also heavier.