A NEW DUNLOP RESILIENT NON-SKID SOLID.
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Using the same Cubic Contents of Rubber, the New Tyre is Claimed to be more Resilient and to Resist Skidding and Side-slip.
Nv"IIILST in very many cases commercial vehicle manufacturers and users are fitting pneumatic tyres to an ever-increasing extent, there will remain with us, for some years to come, vehicles which will continue to require solid tyres. It is difficult to visualize that any simpler or, within limits, more efficient type of tyre than the present solid tyre is possible where it must be fitted, but as the pneumatic tyre possesses great advantages in comparison with the solid, it might be expected that tyre development would tend gradually to confine itself to the former type. Nevertheless, efforts have been made by tyre manufacturers continuously to provide improvements in detail or construction which might enable the solid tyre to meet the general tendencies of demand consequent upon changing conditions of use in a better manner than hitherto. In practically every country in the world the heavy vehicle on solid tyres is regarded with some suspicion in respect to the' extra damage it is alleged to inflict upon roads, -and, granting that for service conditions nothing better can be found than the solid tyre, -damage to roads can be materially reduced by providing increased cushilming in the tyres. As any increase of cushioning which minimizes road damage also benefits the vehicle and its load, by reducing maintenance costs, both the direct and indirect interests of vehicle owners are served by the encouragement of increased cushioning in tyres. Another important aspect is that anything which damages roads also damages tyres, and, therefore, in the long run, the better the tyre cushioning the cheaper the tyre cost per mile must become.
These matters have been under dose investigation by the Dunlop company for a considerable time, and the fullest use has been made of Its splendidly equipped research department and its comprehensive test organization. In addi
tion, the fact that the
The new Dunlop resilient
company has its own and non-skid solid tyre.
associated factories in
other important countries, especially in America, places it in a unique position to interpret world-wide tendencies and to apply world-wide experience in the elucidation of tyre problems. As a result of this continuous application, the Dunlop company has successfully been able. to overcome certain difficulties and to provide a solid tyre in which both the cushioning and skidding problems are dealt with in the best manner possible. The tyre is offered under the name of the Dunlop " Resilient Non-skid," thus Incorporating a description of the improvements in the name itself.
In examining the tyre, the main difference which will be apparent is the series of specially shaped recesses in the sides, regularly spaced round it. Although these recesses are simple in appearance, it must not be thought that they have been arrived at in any haphazard manner. Quite a large number of different shapes or arrangements could be used, but after trial they have had to be discarded in favour of the one found most effective for all the purposes required.
Emphasis must be laid on the fact that the Dunlop company realizes that merely taking rubber out of the tyre is not the best way to improve its performance, as, no matter how the tyre is arranged, a certain' amount of rubber is necessary to give satisfactory service. Therefore, whatever amount of rubber has been removed from the recesses has 'definitely been added to the tyre elsewhere, and the company states without equivocation that t h e qubic contents or quantity of rubber forming the "Resilient Non-skid" is in no case less than that of the
A close-up oiew of the recesses in the new tyre.
solid tyre hitherto o
corresponding plain offered by the
company. Moreover, in some sections, particularly those used for heavy vehicles of the six-tonner class, the quantity of rubber has actually been substantially increased.
Cushioning in solid tyres is practically determined by the amount of displacement or depression under load and by the readiness with which that displacement can occur. The effect of the recesses is to provide increased space into which the rubber can be displaced without resistance, and the reduction of resistance means that the rubber is displaced both to a greater degree and in an easier manner. It is for this reason that the recesses provide greater shock absorption in the tyre as a whole. The recesses are so arranged that, in addition to cushioning, they provide a non-skid effect by breaking up the tread surface into a series of "serrations." These offer a large number of "biting" edges to the road, which, on the slightest sign of ;lipping, tend to sweep or cut away the top surface of "grease," thus allowing the tyre to make the necessary contact with the hard surface beneath and to get the maximum possible grip. Not only does this grip act in a sideways direction, but it is equally effective in a fore-and-aft direction. This adds to the efficiency of the tractive effort, and also increases the effectiveness of braking— a most important point in assisting the driver to keep control and to avoid a possible "smash." The " biting " edges do not diminish with tyre wear. To sum up, therefore, the Dunlop "Resilient Nonskid " solid tyre represents the most modern advance in design. It unquestionably provides greater cushioning and greater safety than ever before, and does so without reducing the life of the tyre. The advantages are offered free of charge io the user, as the " Resilient Non-skid" tyre costs the purchaser no more than the plain solid tyre hitherto offered.