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An operator . fits a new tread to a giant t . nre at Dunlop's factory at Speke, Lircrpool. This 11111

30th July 1965, Page 41
30th July 1965
Page 41
Page 42
Page 47
Page 41, 30th July 1965 — An operator . fits a new tread to a giant t . nre at Dunlop's factory at Speke, Lircrpool. This 11111
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Which of the following most accurately describes the problem?

Retreading Business

As the quality of retreading improves, so the sale of reconditioned tyres increases steadily year by year

By E. JAMES MILLEN WHEN vehicle owners are thinking of buying retreads they probably ask themselves VV two questions, First (most often?): are they economic? Second: are they safe? Judging from the increase in the sale of remoulds in the United Kingdom since 1955 the answers to these questions are tending more and more to be in the affirmative, as since then sales of remoulds for cars have increased every year—from 2m. to nearly 5m. in 1964. And though sales of remoulds for commercial vehicles have risen less dramatically, they have steadily grown none the less—from just over 600,000 in 1955 to 710,000 last year.

Actually, the two questions posed are very closely related. For, in fact, if a retread (or a remould) is safe, it is likely to be economic, as its life is usually claimed by the makers to be anything from 80 to, 100 per cent that of a new tyre—and its costs about half the price (see table).

But are reconditioned tyres safe? Naturally the makers say they are. Tyresoles Ltd., the world's largest retreading organization, answer the question as to safety on motorways—a sore point, this with this statement: "Comparing similar types of tyre under similar conditions, retreads are just as safe as any other lyre. provided always that reasonable precautions are taken with regard to selection of make of retread, casing condition, and tyre maintenance. A reputable retreader will always ensure that the condition of the casing will more than outlast a further !read life." And Dunlop Rubber Co.. Ltd, says: " Retreaded tyres will perform well and give long life, provided a litttle attention is paid to them. Like all tyres. they should be kept at recommended pressures and not abused by kerbing, overloading, or misalignment, They are perfectly safe for motorway use, although it should be realized i hat the retreading process cannot add to a standard tyre casing the vital elements for sustained high-speed motoring which were not there in the first place."

Further evidence of safety is supplied by the numbers of reconditioned tyres which arc used in large numbers by prominent companies. Amongst these are included the largest fleet operator in the country—the General Post 011ice—British Road Services, British Railways, and other nationalized undertakings such as London Transport, the National Coal Board and the Gas Board. they are also widely used on buses, taxis and on aircraft of the major airlines.

A strong argument put forward for retreads by ,Tyresoles is that rally drivers bring them casings to have treated by their process. To no mean end either, it would appear. as the Monte Carlo Rally has been won on Tyresoles three limes since 1453!

The development of motorways in this country gave vehicles the chance to travel at speeds to which they were not accustomed (or suited, in many cases) and afforded opportunities for many people to carp at vehicle shortcomings. Tyres came in for a great deal of criticism, in view of the frequency of

well-publicized "blow-outs ". What happened was that the new conditions showed up the bad tyres—those with inherent weaknesses, which, of course, were just as likely to be " new " tyres as retreads.

The Makers

There can be little doubt that reconditioned tyres supplied by reliable companies are likely to prove entirely satisfactory for normal running when treated with care. Reliable companies? Those such as new-tyre manufacturers (members of the Tyre Manufacturers' Conference), and the 39 independent retreaders who are members of the Retread Manufacturers' Association. But these are far from being the only retreaders. There are in existence a number of additional independent concerns who are not members of the RMA —but the total production of these companies is relatively small. Most of these firms can, of course, be relied upon to do a satisfactory job.

One important distinction between the product supplied by the new-tyre makers and the independents is that the former generally supply bead-to-bead remoulds, whereas the independents tend to retread From shoulder to shoulder only, As far as commercial vehicles are concerned there seems little reason for a full remould, as appearance is not of prime

c12 importance. On the contrary, it appears that retreading offers certain advantages. Attention has been drawn to these by the Goodyear Tyre and Rubber Co. (Great Britain) Ltd., who on announcing recently that all of its plants would be producing Goodyear Super Hi-Miler retreads, declared that the advantages of this process over the "old truck tyre bead-to-bead remould " were better consolidation of rubber, less strains on the casing (ensuring less roadside failures), prevention of exc'ess heat build-up and unnatural flexing, and (barring abuse) more retreads from every casing.

Quality Improved

Unquestionably there has been a great deal of development in tyre quality in the past decade—and this has affected the quality of retreads. It is evident that tread patterns have been very much improved. Even so, manufacturers are obliged to build a safety factor into the original casing which is equivalent to much more than the expected life of the tread. This means that, provided the tyre has been used with reasonable care, when the tread has been worn through the casing will be capable of running for at least ,as many miles as it has already travelled. It is not uncommon for giant tyres to be retreaded several times.

It is the tyre casing that is the crux of the remoulding process. Before cases are considered suitable for reconditioning they are examined in extreme detail. Members of the RMA subscribe to a "Code of Minimum Standards".

This code sets out minimum acceptable casing standards, specifies the maximum amount of damage that can be repaired, and lists methods to be used in effecting those repairs. Most of the damage is usually visible, but an air-injection needle is normallt used to check on possible points of separation of the casing plies. Many companies find that they are forced to reject as many as 30 per cent of the casings tested.

On the initial visual inspection common failings are: discoloration of the sidewall interior because of heat build up, usually as a result of under-inflation; injuries through penetrations; and damage to bead because of excess of friction between tyre and wheel often as a result of under inflation or overloading. Obviously overloading and under-inflation will impose severe stress on tyres: other factors contributing to stress are fitting the wrong size tyres and incorrect ply rating of tyres in relation to the load • carried.

When should a tyre be taken off to make it suitable for retreading? Ideally, as soon as the tread pattern is worn through. This is for several reasons: first and foremost, additional wear will very likely lead to tread cuts, likely to make the tyre unsuitable for retreading; secondly, when the tread pattern is worn through tyres will not grip; thirdly, running. on bald tyres is an offence under the Road Traffic Act.

Records Not Kept

One point that surprised me considerably when making inquiries about the use of retreads by hauliers was the number of occasions on which I was told that records of tyre life were not kept. Surprising indeed when one considers the amount of money spent on tyres—reputed to represent from about eight to 18 per cent of total maintenance costs.

The GPO, for instance, informed me that "No strict records of tyre life are kept ". And transport contractors W. W. Drinkwater (Willesden) Ltd., who told me that they use a small proportion of retreads on their 120-vehicle fleet, also said: "We do not have reliable records as to replacements for the reason that much damage is suffered at building sites and shoots, especially house refuse tips where tyres are cut by glass. A tyre is not reserved for any particular vehicle and during its life it may be on a number of vehicles following puncture or other damage."

This subject was also raised when I visited Tyresoles factory at Wembley. An executive of the company stated: "Accurate records of tyre mileage are no longer kept, probably because of staff shortages."

Retreaders are usually supplied with casings from garages and distributors and most companies retread tyres made by other rePutable companies. But it would not do for retreading to become too popular—for in such circumstances where would the casings come from? Some five years ago the ratio of retreads to new types for replacement purposes was of the order of 60 : 40, but this has now been reversed—a situation which is most desirable from the point of view of the retreaders.

Own Casings Returned

In the giant-type range it is not unusual for an operator to insist on having his own reconditioned casing returned to him, and this presents no particular problem. Both tubed and tubeless tyres can be remoulded, the latter normally

being a Tittle more expensive, and so, also,, can both cross-ply and radial-ply tyres. It is interesting to note that Tyresoles have special equipment available_ to treat rigid breaker tyres in the giant range, and by Michelin's. Giant " X" Rebuildex process, tyres made by the company can be completely renewed (both tread and bracing plies are removed and new bracing plies and tread bonded to the easing).

The procedure that 'follows is the one :tdopted by Dunlop at their new Speke plant, and it is typical of any modern retreading process: 1, inspection: 2. drying out; 3,buffing; 4, further. inspection:. 5. adhesive applied. (for retaining applied tread only); 6. new strip of tread rubber applied: 7, futher inspection; 8, vulcanizing; 9, further inspection; and 10, wrapping and dispatch.

A man with much to _say on the retreading of tyres in general and the abuse of tyres in particular is Mr. George Mainland, process controller of the Tyresoles plant at Wembley, Middlesex. He knows his subject, as well he might, since be has been in the business a long time— laid at Wembley for close on 20 years. Things like easing injuries and deflation damage irritate him considerably, and very soon indeed after 1 was introduced to him he was impressing upon me how important it was that correct ply ratings should be used.

7' If transport people would take care of their tyres they would save themselves a lot of money ", he said. " Good maintenance and avoidance of overloading are the prime factors.—tyres don't get the attention they merit. Other maintenance is carried out. It is part of a driver's job to see that his tyres are in good order --he should have a quick look round before every trip, and all the flints stuck

in the tyres should be removed: But what happens? All the tyres get is a quick kick--and off they go!"

A development of considerable interest in the retreading field is the Kentredder system; This, in effect, is a do-it-yourself retread outfit which, I Understand, is a

procedure quite widely used Is America. The Kentreckler system (a full account of which appeared in The Commercial Motor oil January 10, 1964) prOduced what is gencral4 called a re-cap tyre--that is. the new rubber is applied as a parallel strip and does not extend at all down the sidewall. For a fleet operator the equipment required would probably comprise a huller/spreader unit, two control panels, probably three moulds for different Is re sizes, tyre spreaders, pressure hags and so on. It is claimed to be cornparati‘ely simple to operate and to be both ellective and safe. How much does ii cost? The equipment is supplied on a rental basis and would cost about 1650 a year. including an annual service charge. Retreads made using the Kentredder s■stern are now available from coneessionmiires covering two-thirds of the countr:s.

Recut Tyres

And Ak'hat of teems? A great deal has been said and written on this subject in the past 12 months, most of it with some vehemence. And it is likely, 1 -understand, that legislation will be brought in to deal with the matter before long.

'Elle situation is. I think, nicely and concisely explained by Dunlop. They say: "'file description recut ' applies onb to a is re that has reached the stage where the original tread has worn away and attempts are then made to cut the semblance of a pattern into the thin undertread ruhher. There is a very real danger at this stage of cutting deeply into the easing cords and weakening the tyre casing to a dangerous point. 1 his practice is to be deplored and not coumenaneed by any responsible tyre manufacturer or retreader. There is only one exception to this. There is a special grade of commercial vehicle tyre built with a deep undertread especially for regrooving when the first tread is worn away. These tyres are not in use oil cars or light vans and are primarily designed for low-speed public service vehicles where safety stipulations are exceedingly tough." To which, "Amen When I raised this particular subject with Mr. Mainland he looked, 1 thought, slightly shocked. '' Cutting?" he said. " Some scrap tyre dealers do it. Sharks!" He hastened to assure me that Tyresoles do not accept tyres for remoulding if the% have been regrooved. His last words on the subiect: " Recutting on anything except p.s.y.s is out!"

To sum up then, the future of retreads both in this country and abroad— looks distinctly brieht. Sales are now increasing every year. steadily and regularly. The actual figures for remould sales in 1964 were: car sizes, 4,914,736; commercial vehicle sizes, 721,878. And by the end of 1967, Dunlop (who claim the lion's share of the market) reckon that these figures will increase to six million plus and 750.000 respectively. Since !he new-tyre makers tend to be extending their activities in this particular direction and taking a larger share of the market, it seems very likely that these estimates are far from over-optimistic.

FIRMS THAT RETREAD

Members of Tyre Manufacturers' Conference

Avon Rubber Co. Ltd., Melksham, Wilts. Bereougnan Rubber Co. Ltd., 95-100 White Lion Street, London, Ni.

Dunlop Rubber Co., Fort Dunlop, Erdington, Birmingham 24.

Firestone Tyre and Rubber Co. Ltd., Great West Road, Brantford, Middlesex.

Fisk Tyres Ltd., 1 Frederick Street, Riddings, Derbyshire.

Goodyear Tyre arid Rubber Co. (Great Britain) Ltd., Bushbury, Wolverhampton, Staffs.

Henley's Tyre and Rubber Co. Ltd., Hentey's House, Randolph Avenue, Maida Vale, London, W9, India Tyres Ltd., Inchinan, Renfrewshire, John Bull Rubber Co. Ltd., Allington House, 134 Victoria Street, London, SVV1. Kelly-Springfield Tyre Co. Ltd., 1-3 Redhill Street, London, NW1.

Michelin Tyre Co. Ltd., Stoke-upon-Trent.

North British Rubber Co. Ltd., Castle Mills, Edinburgh.

Pirelli Ltd., Derby Road, Burton-upon-Trent.

Members of Retread Manufacturers' Association

Amos Tyre and Rubber Co. Ltd., Maury Grove Road, Cheshunt.

Rarwell Rubber Co. Ltd., Swavesey, Cambs, Bellamy's Tyre Depot Ltd., 25-27 Stafford Road, Croydon.

Blue Peter Retreads Ltd., Basingstoke. Hants. Brimelow, James, 111 Manchester Road, Bolton. Brown's Tyre Service Ltd., 122 Junction Road, London N19, Bussey Bros. Ltd., 39 Palace Street, Norwich. Cedo Tyre Co., 104-106 The Hornet, Chichester, Channel Islands Tyre Co. Ltd., 32 The Parade, St.

Helier, Jersey.

County Tyre and Rubber Co. (Bristol) Ltd., H.I.

Factory, Chittening Estate, Avonmouth, Bristol.' Ferdix Rubber (London) Ltd., Coldharbour .Lane House, Coldharbour Lane, Hayes. Middx, Fit Ltd., Amenbury Lane, Harpenden, Herts. Goodline Ltd., 201-207 Castlereach Road, Belfast, 5 . Hale End Tyre and Rubber Co. Ltd., Hampshire Works, Station Road, London E17.

Hill's Tyre Services Ltd., Tyre House, London Road, Newbury, Berks.

Homerton Rubber Works Ltd., Bravington Road, Kilburn Lane, London W9.

Treforest Trading Estate, Pontypridd, S. Wales. Marshall For Tyres Ltd., Oxford Road, Clactonon-Sea, Essex.

Martin Walter Ltd., 145-147 Sandgate Road, Folkestone, Kent.

North Hants Tyre and Remoulding Co. Ltd., 18 Fleet Road, Fleet, Hants.

Notts Tyre Rebuilding Co. Ltd., 98 Canal Street, Nottingham.

Ondure Ltd., Victoria Park Mills, Hard lags Road, Keighley, Yorks.

Pike Tyre and Rubber Co. Ltd., Pear Tree Hill, Skifords, nr. Redhill, Surrey.

Radnorshire Tyre Services Ltd., Knighton. Radnor. Regent 'Tyre and Rubber Co. Ltd. Newcraft

Works, Commercial Road, Edmonton, Condon N18. Reynolds and Rees Tyre Services, Colchester

Estate, Colchester Avenue, Cardiff.

Seagrave Tyre Co., Seagrove Road, London 5W6. Southern Tyre Co. Ltd., Manor Road, Hurstpierpoint, Sussex.

Super Retreads Ltd., 92-96 Acre Lane, Brixton, London S W2.

Thompson-Reid Ltd., Donegal Square, Belfast. Tyres (Scotland) Production Ltd., Gayfield Works, Prestanpans, East Lothian.

Tyreservices (Plymouth) Ltd., Greenbank. Plymouth, Tyresoles Distributors (Brighton) Ltd., Coalb rook Road, Brighton.

Tyresoles Ltd., Palace of Engineering, Wembley, Middlesex; Buckingham Road, Heaton Moore, Stockport: Victoria Works, Station Road, Old Hill, Staffs; Bradley Lane, Newton Abbot, DeVon.

Vacu-Lug Traction Tyres Ltd., Gonerby Hill foot, Grantham, Lincs.

Victory Tyre Works, PO Box 7, Woodgate, Leicester.

Warco Tyres Ltd., Burton Street. Peterborough. Watts Tyre and Rubber Co. Ltd., Lydney, Glos.. Webster Tyre Co. Ltd., Hyperion House. Hutcheon Street, Aberdeen.

Young (Motors) Ltd., H., PO Box 3, Sturdiluxe Works, Foundry Lane, Chester-Le-Street, Co.

D.

In addition to these companies there are numerous other independent retreaders. Some 25 companies belonging to the UK Kentredder Association process tyres using the Kentredder system. Details of these firms cart be obtained from Retreading Equipment Lcd., Anstey Mill Lane, Alton, Hants.


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