WHY RETREAD? Cost :Retreaded tyre cost far less than new one, specially for truck, OTR tyre.

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1 Presented by- POULOMI DASGUPTA Department of Polymer Science & Technology University of Calcutta 92, A.P.C Road, Kolkata

2 Introduction Retreading is a safe, efficient and environmentally friendly way to breathe new life into worn tyresby assessing its integrity throughout the entire process.it is a modern, hi-tech process with a long pedigree in efficiently managing scarce resources.the damaged tread is replaced with a brand-new one and this means that the tyrecan be used again! It preserves about 90% of the materials in spent tyresand material cost is ~20% compared to manufacturing a new tyre.

3 WHY RETREAD? Cost :Retreaded tyre cost far less than new one, specially for truck, OTR tyre. As good as new tyre: better safety, outperforming the original new tyre in wear, efficiency and traction. Far more flexible : Variety of tread design & size which enables fleet managers to have far more flexible tyre programme than new tyre. Cutting life cycle cost : A quality retread gives more miles, there is no loss in the performance from the original tyre.

4 WHY RETREAD? Stronger casings, improved re-manufacturing techniques, a variety of specialist rubber compounds, coupled with the need to recycle and reduce the negative impact on the environment has lead to a sustained growth in the retread industry. Benefits: Commitment to the environment Reduce pollution Conserve oil Less energy Conserve resources

5 STEPS OF RETREADING Initial inspection Buffing Here the decision is made whether to retread or not. Expert inspection assures every casing that can be retreaded is, and every casing that can t be returned to service isn t. The first saves you money; the second, downtime. Buffing is simply the removal of previous tread casing surface to receive the new tread. The casing is buffed as flat as possible so there will be good tread-toroad contact. Buffing Process Casing preparation Injuries remaining or uncovered after buffing are then repaired. This involves skiving or buzz out of the injury with a powered rasp. Casing Preparation

6 STEPS OF RETREADING (Contd ) REPAIR Repairing involves the removal, filling, and reinforcing of the injury and surrounding area. Nail hole Spot Reinforce- Section repair repair ment repair repair

7 (Contd )

8 STEPS OF RETREADING (Contd ) REBELTING A knife cuts under the belts and peels them off the casing. When the belts are removed, the casing is buffed, prepared, and cemented. Then two new belt assemble packages are added, followed by standard retreading procedures. TREAD APPLICATION After repairs are made, the casing is then sprayed with cement to enhance adhesion between the new tread material and the casing. When the cement dries to a tacky consistency, it is ready for the tread.

9 STEPS OF RETREADING (Contd ) CURING Done in both autoclave and mold; after specific time, temperature and pressure, the tread becomes bonded to the the casing. FINAL INSPECTION The inside is checked to make sure all patches are properly bonded, DOT number (showing name of retreaderand time of retreading), the tire is then trimmed of rubber flashing or overflow, staples are removed, the tire is painted, and tagged for delivery.

10 TYPES OF RETREADING PRE CURE/COLD CURE : Previously cured tread strip is applied to the buffed tyre casing with cement and the whole assembly is put in autoclave for final curing; most commonly used method but results in a seam where the end of the strip meet.

11 COLD CURE PROCESS

12 TYPES OF RETREADING MOLD CURE/HOT CURE: Raw rubber is applies to the tyre casing and then it is placed in a moldwhere the tread is formed. A dedicated moldis required for each tyre size & design.

13 HOT CURE PROCESS

14 EXPERIMENTAL DATA The tyrewas rotated and wear was measured in mm at different interval. Same procedure was done for new and retreaded tyre. And tread wear was obtained against different speed and different load.

15 ANALYSIS From above graphs it is concluded that for same travelling distance of new and retreaded tyre, tread wear for new tyreis less than the retreaded tyre. Because of hard rubber ply in new tyre, wear resistance is also high. Total travelling distance of retreaded tyreis more than that of new tyre. The 3 rd graph illustrates the financial advantage of retreading. Assuming that a retreaded tyrecosts 25-30% of a new tyreand that both tyreshave almost equal useful lifetimes in terms of kilometres, tyrecosts will be reduced by up to 30 per cent if the tyrecasing is retreaded two times. Retreaded tyrehave 77% life from 28% cost compared to new tyre and 2nd time retreaded tyrehave 40% life from 28% cost.

16 MARKET PLACE

17 GLOBAL TREND Bandagtechnology was introduced in 1957, the company was a pioneer in the commercial retreading process for truck tires. Over the past 60 years, Bandag has reinstated 300 million tires, saving 15 billion liters of oil. It is estimated that there are approx. 5 million EU Commercial Retreads manufactured each year. NEW Vs RETREAD Ratio: 1:1 -UK commercial vehicles are running on Retreaded tyres (Estimated) In Italy the government has specified that at least 20% of state owned vehicles must drive on Retreads. When compared globally, the share accounted for by sales of retreads in Finland is particularly high for heavy vehicles. About 3.3 million passenger car and van tyresare sold each year in Finland. 2-3 per cent of these are retreaded. Almost 300,000 truck, replacement truck tyresare sold annually, of which 70 per cent are retreaded. The environmental saving are staggering Average savings per truck tyre: 44 Kg of rubber ; 68 litres of oil ; 182 Kg CO2.

18 Is it safe? Do they last long? Is it worth buying?

19 CONCLUSION More than 85% commercial fleets retreading their truck tyres multiple times and the cost is approx one third to one half the price of a new tyre. It is obviously fleet s bottomlineinterest to maximize the number of retreads for each and every tyre casing. Today s product embodies the latest in materials science and manufacturing technology to deliver performance equal to the original new tyre. Strict regulation and rigorous quality control ensure that the customer can buy with confidence. There will be a clear demand for retreading in the future as quality, economy and environmental issues become even more important. Attention will be paid not only to the useful lifetime of a tyrein terms of kilometres, but also fuel efficiency, wet grip and external rolling noise.

20 References : VankarBharat A, GosaiDipakC, Shah AmitV, An Experimental Analysis on Life Cycle of TyreRetreading, International Journal of Advance Research In Science And Engineering, 2015, Vol. 4 Truck Tyre Retreading : A guide for fleet owners, managers and specifiers, Prepared by Bandag,incorporated. Retreaded Tyres: Quality, Economy and Eco-efficiency, Ed.-Jouko Lahti, JL Interaction Tmi, Publisher: Tyre Specialists of Finland

21 ACKNOWLEDGEMENT I want to thank the organising committee of ASIA RUBTECH EXPO 2018 for providing me the opportunity to deliver the presentation in this International Conference. I am also thankful to TEQIP phase III for providing me the financial assistance to take part in this conference.

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