With one layer of nylon wrapped from bead to bead, a single ply
conforms well to the terrain and offers a reasonable weight.
A sturdy material is needed to hold the tire against the rim when
inflated. Wire is used to ensure the bead will not expand, but wire
is also heavier.
A foldable bead also stays tight to the rim but is lighter weight
and easier to transport. The bead created of an Aramid or Kevlar®
The number of nylon threads that cross through one square inch
of the tire’s casing. Lower TPI provides improved puncture and tear
resistance, but also increases the overall weight of the tire. Higher
TPI conforms more to the terrain, offering a smoother, more supple
ride and offers a lighter weight construction.
CST TPI ratings are the threads-per-inch of a single ply casing, as
compared to some competitor TPI ratings.