Glossary - CEMB SM675TI Manuel D'utilisation

17. GLOSSARY

Wheel and tyre assembly
Set consisting of:
Tyre
Wheel: union of rim and disc
Inner tube (if any)
Air under pressure
I - TyreThe 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 com-
pound 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 com-
prises 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
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