How Giant Tyres are Rebuilt
Page 37
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WITH the 'object of overcoming the prejudice against retreaded tyres, the English Tyre and Rubber Co., Ltd., 43, Johnson Street, London, S.W.1, concentrated for six months on the introduction of a new method of re-rubboring giant pneumatic tyres, carrying out extensive road and laboratory tests. At the end of this period the E.T.R. reconstructed giant pneumatic tyre was placed on the market.
New treads are not put on'to-the old tyre wallsand before the casings are re-rubbered they are bared of the original rubber, together with the bead strips. The company stresses the importance of these factors; if the casings be not stripped, it is impossible to determine whether they are entirely free from fatigue; ply separation,dampness in the beads, etc., as well as from cuts. It soon became clear that in order to obtain consistently satisfactory results tyres should be rebuilt in full-circle moulds that cover the beads.
Before accepting a casing, the English Tyre and Rubber Co., Ltd., Makes certain that it is up to standard, and if it be not it is rejected. The method of rebuilding is similar to that employed in the manufacture of new tyres and it includes the fitting of new breakers
and bead strips. Following this the tyres are cured in full-circle beadcovering moulds in an Autoclave press.
When the various processes are completed the rebuilt tyre is difficult to distinguish from a new one, except, of course, for the feet that the word "reconstructed" is engraved on the walls.
A variety of sizes is available, ranging from 30 ins. by 5 ins. to 40 ins. by 8 ins., and the reconstructor claims useful mileages. The trade price of a tyre measuring 30 ins. by 5 ins. is 12 5s., for 38-in. by 7-in, equipment— a size popular with operators of heavy vehicles—it is £4 us., -whilst the largest model of 40 ins. by.8 ins. costs XI 2s. 6d.
The English Tyreand Rubber CO., Ltd., provides a written guarantee of mileage for every tyre that it rebuilds.