| 1. | Tyre with Cotton (reinforcement) Carcass : |
| 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 : |
| 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 : |
| 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 (ie 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) : |
| 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 : |
| 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 : |
| 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 : |
| 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) : |
| 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 : |
| 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 : |
| 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 : |
| 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 : |
| 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 eg 190 kmph, 210 kmph etc. |
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| 13. | High Performance Passenger Car Radial Tyre : |
| 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 : |
| | 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 : |
| 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) : |
| 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. |
