CEMB SM628TI Manual De Uso página 53

rim. The bead point (a) is the inner corner. The spur
(b) is the inner part of the bead. The base (c) is the
area resting against the rim. The groove (d) is the
concave part against which the rim shoulder rests.
Tube type tyres. As a tyre has to contain pressurised
air for a long period of time, an air chamber is used.
The valve for inserting, maintaining, controlling and
restoring pressurised air is, in this case, part of the
chamber.
Tubeless tyres. Tubeless tyres consist of a tyre
EN
with inner sidewall lined with a thin layer of special
impermeable rubber, called a liner. This liner helps
to maintain air pressure in the casing. This type of
tyres must be mounted on specific rims, on which
the valve is fixed directly.
II - Rim (Wheel). The rim is the rigid metal part which
connects the vehicle hub to the tyre, on a fixed but
non-permanent basis.
a
c
b
Rim profile. The rim profile is the shape of the
d
section in contact with the tyre. It is made with dif-
e
ferent geometric shapes that serve to ensure: easy
assembly of the tyre (inserting the bead into the
channel); safety on the move, in terms of anchoring
the bead in its seat.
i
When observing a section of the rim, it is possible to
g h
identify different parts that compose it: a) rim width – b)
shoulder height – c) tubeless anchoring (HUMP) – d)
valve hole – e) ventilation opening – f) offset – g)
f
central hole diameter – h) connection hole centre to
centre distance i) keying diameter – j) rim channel.
III - Air chamber (tube type tyres). The air chamber
j
is a closed ring-like rubber structure with a valve,
which contains pressurised air.
Valve. The valve is a mechanical device to inflate/
c
a
b
deflate the tyre and maintain air pressure inside the
air chamber (or tyre in the case of tubeless tyres).
It consists of three elements: the valve closing cap
(a) (to protect the internal mechanism from dust and
guarantee air tightness), an internal mechanism (b)
and the base (c) (the outer lining).
Tubeless Inflator. Inflation system that makes easier
the inflation of tubeless tyres.
User's manual 53