| 1. |
Tyre
with Cotton (reinforcement) Carcass : |
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In
the starting phase of proper Bias or Cross ply tyre,
cotton plies were used as main reinforcing material
(end of 19th and early 20th Century). Cotton reinforcing
material had inherent problems of low strength and high
moisture regainer. Leading to large number of plies
to get the requisite casing strength for the tyre weight
of the tyre and poor heat dissipation. This, in turn,
gave an adverse impact on Tyre weight and buck rendering
poor performance. |
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| 2. |
Tyre
with Rayon (reinforcement) Carcass : |
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With
the development of viscose and rayon the strength of
reinforcing material went up and found application in
tyres in early 20th Century. Due to higher strength
of rayon it was possible to reduce number of plies and
weight of the tyre. Since less number of plies were
needed to match cotton strength, concept of ply rating
developed. It was also possible to have higher ply ratings
now. |
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| 3. |
Tyre
with Nylon (reinforcement) Carcass : |
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Persuent
to development and introduction of Polymide (Nylon)
the strength and flexing behavior of reinforcing materials
improved substantially resulting in further reduction
of number of plies, consequently the weight of the tyres.
This development substantially improved the heat and
impact resistance of the carcass leading to better tyre
performance and higher durability. Nylon casing gave
a boost to retreadability. Thus effective cost of the
tyre in operation became much more economical.
Development
of Tyre Technology due to change in Reinforcing material
is basically in the case of Cross Ply or Bias Tyres.
Bias tyre has cotton, Rayon or Nylon Cords, bound
as plies and each ply (i.e. Cords) cross each other
at a definite angle anchoring at the bead.
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| 4. |
Radial
(Construction) Tyre - Textile/Textile belt (Rayon/Nylon/Polyester)
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Inspite
of continuos development in Bias Tyre Technology, inherent
problem of high heat development and poor life remains
a continuos challenge.
In
early 1950s new concept of Tyre design was developed
namely "RADIAL" wherein plies were made highly flexible
by keeping the cords at 90 and in order to improve
tyre life, inextensible (stiff) belts were placed
on the top of the Carcass under the tread. This led
to stiffer tread portion, leading to higher Tread
life (Mileage) and much more comfortable ride due
to flexible carcass. This was the beginning of 'Revolution'
in tyre technology.
Initially
Radial tyres were introduced with Casing Plies as
well as belt material of textiles.
Continuos development in Radial
Concept led to further improvements as explained below.
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| 5. |
Radial
(Construction) Tyre - Textile/Steel belts : |
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Once
Steel Tyre cord got developed it found its immediate
application in Belt material, keeping casing plies of
Textile, to further improve durability. |
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| 6. |
Radial
(Construction) Tyre - Textile/Glass Fibre Belt :
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Similarly,
development of glass fibre which is practically inextensible,
led to application in passenger and Light Commercial
Vehicle tyres with Textile Casing, providing corrosion
free radial Tyre belt material. |
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| 7. |
Low
Aspect Ratio (Cross Ply or Bias) Tyre : |
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A
new concept of low aspect ratio (ratio between section
height and section width) of the tyre in cross ply construction
was introduced for higher speed and better performance.
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| 8. |
Tubeless
Tyre (Cross Ply) : |
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Concept
of tubeless tyre in cross ply construction wherein an
inner liner compound based on chlorobutyl or Halo Butyl
which is impermeable to gases, was introduced eliminating
the usage of tubes. This concept could not find sustained
application in India due to bad roads and poor handling/maintenance
of Rims other than in OTR range. However, Tubeless tyres
are produced for Export Market.
Gradually
this concept will become fully acceptable with the
advent of new generation vehicles and improved service
facilities.
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| 9. |
Radial
(Construction) Tyre - Textile/Aramid Belt : |
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Due
to poor roads and inadequate vehicle maintenance, Steel
belts had corrosion problem due to cuts and chips in
the tread. This led to trials with Aramid belt (Textile
material with very high strength and Low extensibility).
However,
this could not find any sustained use.
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| 10. |
Radial
(Construction) Tyre - All Steel : |
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In
developed countries, Radial Truck/Bus tyres use steel
wires in casing as well as in Belts to achieve the optimum
advantage of radial construction. In India also this
construction was tried since late 1970s by Indian Companies
using tyres of collaborators. This could not succeed.
Indian
companies started experimentally since late 1980s
(themselves or with collaborators) which continues
and the product has found gradual entry into low load
application.
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| 11. |
Tubeless
Tyre - Radial Construction : |
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As
in the case of Bias Tyres, the concept of tubless tyre
was extended to radial construction and introduced in
later half of the century in Developed countries. A
tubless tyre not only has tube eliminated but provides
for smoother ride and vehicle handling. This is slowly
entering into the Indian market with the advent of new
generation vehicles. |
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| 12. |
Low
Aspect Ratio - Radial (Construction) Tyres : |
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The
concept of low aspect ratio tyre, after gaining the
experience from cross ply construction, was introduced
in Radial construction also. The present trend of tyre
development for high speed tyre is being pursued in
this direction. Tyres with aspect ratio upto 0.65 are
being manufactured today enabling Indian Industry to
adopt high speed rating e.g. 190 kmph, 210 kmph etc. |
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| 13. |
High
Performance Passenger Car Radial Tyre : |
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High
Performance Passenger Car radial tyres not only have
very low aspect ratio (0.65 - 0.35) but also have substantial
changes in construction. Very low aspect ratio enables
use of large diameter wheels which, in turn, allows
better stability at high speeds. The tyre contour is
based on the cross section of a fully loaded tyre and
this reduces the energy losses within the tyre and reduced
dynamic fatigue. High performance Passenger tyres are
made with speed rating upto ZR indicating speed
capability in excess of 240 kmph. In India, this
concept has not yet been found popular though customers
are demanding tyres upto 220 kmph (V Rating). |
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| 14. |
Run
Flat (Puncture Proof) Tyre - New Concept : |
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A
new concept of run flat tyre (puncture proof)
was introduced by Continental in early 1980s wherein
the basic construction of the rim and bead was changed
by which on loosing air the tyre tread sits on the rim
thus enabling one to drive at a reasonable speed for
a long distance till the flat tyre could be attended
to.
This
revolutionises the OE need for a new vehicle as the
Stepney tyre can also be dispensed off. However, there
is very slow progress of this concept. This has not
been tried in India so far.
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| 15. |
Fuel
economy/low rolling resistance tyre - special compound
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Tremendous
work is being carried out towards the development of
tyres with modified special compounds, besides tyre
construction aspect, to reduce rolling resistance thus
gaining in fuel consumption. However, the ultimate advantage
is obtained by Radial Construction which is gradually
findig its well deserved place in Indian Industry. |
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| 16. |
Green
Tyre (Environment Friendly) : |
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This
is the latest development in Passenger Radial tyres.
These tyres have a rolling resistance appreciably lower
than normal tyres. These tyres have high proportion
of non petroleum based material used in their construction
and are called environment friendly or 'green
tyres'.
This
concept is well perceived and will gradually find
its application world over, including India.
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