immer-mobil TCN 8200 Mode D'emploi page 124

15. GLOSSARY
Wheel and tyre assembly
Set consisting of:
Tyre
Wheel: union of rim and disc
Inner tube (if any)
Air under pressure
I - Tyre The tyre is the main part of the complex that is
in contact with the road and is therefore designed to
support the internal air pressure and all other stresses
arising from use.
The tyre section shows the various parts it consists of.
The tyre must:
- withstand a load,
- ensure driving power,
- steer the vehicle,
- aid handling and braking,
- aid vehicle suspension.
1 - The tread. It is the part in contact with the road while
the tyre is rolling. It comprises a rubber compound and
a "pattern" suitable for ensuring good resistance to
abrasion and good grip in dry and wet conditions, as
well as quiet operating conditions.
2 - Edge or bracing. It is an insert of metallic or textile
fabric, placed at the outer part of the bead; it is used
to protect the carcass plies from sliding against the rim.
3 - Casing. This is the resistant structure and comprises
one or more layers of rubber plies. The way the plies
comprising the casing are arranged give the structure its
name. The following structures are possible:
Conventional: the plies are inclined and arranged so that
the strands comprising a ply overlap with those of the
adjacent ply. The tread, which is the part of the tyre in
contact with the ground, is part of the sidewalls and so
during rolling, sidewall flexure is transmitted to the tread.
Radial: the casing consists of one or more plies with the
cords in radial direction.
A radial casing in itself is quite unstable. To make it stable
and prevent incorrect tread movement in the area of
contact with the ground, the casing and the shim under
the tread are reinforced with an annular structure, usually
called a belt. The tread and sidewall work with different,
independent rigidities, so during rolling, sidewall flexure
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