From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Article from 'The Autocar' detailing the design and performance of the Stelastic Tyre.
| Identifier | ExFiles\Box 1\7\ B001_X15 20 46 50 59-page109 | |
| Date | 5th October 1912 | |
| R.{Sir Henry Royce} R.{Sir Henry Royce} 235A (150 H) (S.A. 301. 19-2-15) G 0950. X20 X1703 624 THE AUTOCAR, October 5th, 1912. The Stelastic Tyre. Small Interlaced Steel Springs incorporated with the Rubber Tread. CONSIDERABLE interest is being centred in the Stelastic tyre, the production of Torkington Tires, Ltd., 76, York Street, Westminster, which is now undergoing a 5,000 miles trial under the auspices of the Royal Automobile Club. In a recent issue we mentioned this fact, and made a short reference to the nature of the tyre. Up to the present no full description nor illustration has been given of this interesting cover. The idea of armouring the tread of a tyre so that it is rendered practically unpuncturable and its life is prolonged by means of wire or other metal device is not a new one, but in the tyre under review we have something on different lines from previous designs. The Stelastic cover possesses an ordinary carcase of the best quality which presents no innovation, but it is in the tread that the whole novelty lies. This consists of numerous interlaced springs of piano wire standing up on end and woven into a fabric, and into which rubber is hydraulically forced at a pressure of 75 lbs. per sq. in. It is then guillotined into strips, which are placed upright side by side and form the tread. The accompanying illustration shows clearly what is meant. The result is a tyre with a tread which is claimed to be practically puncture-proof, very durable, and possessing certain non-skid qualities. The resiliency, it is said, is in no way affected, as when the rubber is compressed by the weight of the car, the springs are compressed in harmony. We were shown the portion of an early pattern tread of a worn out tyre, in which it was seen that the rubber and steel springs (though the latter in this case were not tempered) do not part, while, owing to the piece of fabric and rubber beneath the armoured tread, the springs do not cause punctures by penetrating the main fabric. There are 90,000 springs in an 880 x 120 mm. tyre, so it will be seen that at the point of contact on the road a large number are compressed. It is claimed that the amount of wear experienced during 1,000 miles running is about one-sixteenth of an inch. To revert to the non-puncturable properties of the tyre. The only thing which, it would appear, can penetrate it is a thin nail striking the tyre at just the right angle and entering between the springs. Stelastic tyres which we have seen fitted to a heavy 40 h.p. Daimler limousine show no signs of cuts after long use. In fact cuts of any appreciable size would seem to be almost impossible on the armoured tread. As regards non-skidding qualities, firstly the adhesion on dry roads is excellent, while the tyre is an effective non-skid, we are told, on wood paving, asphalt, and stone setts. On greasy macadam, however, it seems evident that a studded cover would score over this particular pattern, at any rate in its present form. It is stated that the tyre keeps cool, as the steel radiates the heat generated. It is interesting to note that the tyre is British made. Fig. 1.—Part section of the Stelastic tyre, in the tread of which almost innumerable small interlaced springs are amalgamated with the rubber. Fig. 2.—The interlaced springs of the Stelastic tyre. A few of them are shown above before being embedded in rubber and cut off to the correct length, i.e., about six coils. | ||