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).
Letter from D.R. Co., Ltd. concerning issues with tyre security bolts, pressure, and test results.
| Identifier | ExFiles\Box 45\1\ Scan276 | |
| Date | 26th July 1922 | |
| A121 D.R. CO., LTD. CONTINUATION SHEET No. 1. 26th July 1922. Dict. 25th. Messrs. Rolls Royce Ltd. bolt, and the severe local stretching of the tube over the sharp edges does actually in some cases cause a minute abrasion, or puncture, which quite unknown to the user reduces his inflation pressure, and by permitting the bead to move, allows the tube to get under-neath it and force the bead over the rim. In all cases, and we may say they are not peculiar to Rolls Royce Cars, where we have removed these security bolts the trouble has disappeared, but as far as the Rolls Royce vehicles are concerned, we find we are up against a definite recommendation from you that security bolts must be used. We, therefore, thought it necessary to put before you the position, with a view to satisfying you that the circumstances in connection with Cord Tyres having changed, no good purpose is now served by insisting upon the use of security bolts. The official recommendations of the Dunlop Company, for which we are prepared to take the fullest responsibility, are contained on pages 23 & 24 of the enclosed booklet "Dunlop Tyres of 1921-22", and also on page 15 of the booklet "The Care of Tyres" enclosed herewith. In addition we have undertaken a series of tests on the test Rolls Royce Car which we previously owned, and have quite satisfied ourselves that creeping or blowing off does not take place until the tyre pressure has fallen dangerously low, say to the order of 10/20 lbs per square inch. In this case, while we actually failed in test to get the tyres to blow off, we did get them to creep considerably, and the presence of | ||