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).
Examination of a twisted front axle on a 3 1/2 litre Bentley, discussing the cause, potential remedies, and history of similar issues.
| Identifier | ExFiles\Box 84\3\ scan0212 | |
| Date | 9th April 1934 | |
| x201 To Wer. from R/Lid.{A. J. Lidsey} c. Hs.{Lord Ernest Hives - Chair} Hy.{Tom Haldenby - Plant Engineer} Hd.{Mr Hayward/Mr Huddy} The 3½ litre Bentley No.B.75.A.E. Crossman. We have carefully examined the twisted front axle removed from the above car. The twisting is due to a very violent brake application having been made. Actually the n/s pivot had twisted 7° and the o/s pivot 3½°, producing a pivot lean of 2° forward on the n/s and 1° backward on the o/s; the result of this would be to produce an unstable, but not dangerous, steering. Two axles have been twisted in a similar manner, due to very violent brake application and brake juddering in the Experimental Department and as long ago as the 6th September 1933 the axle was stiffened up at the point where the twisting takes place. Unfortunately a considerable number of axles of the weak type had been ordered and were in existence at this time and the defect was not considered to be sufficiently serious to warrant scrapping all these axles. Actually there are 181 cars in existence with the weak axle. At the moment there is no actual proof that the stiffened axle will overcome the trouble; chassis 4-B-1V has completed 20,000 miles in England with the stiffened axle but has not yet been checked for twisting. We have asked the Experimental Department to do this. We expect the modified axle will overcome the trouble because the increase in stiffness occurs exactly where the twisting takes place. Brake juddering at high speeds is believed to be the cause of the twisting; it is very doubtful if ordinary brake application will produce it. It would appear advisable to examine cars known to have suffered from brake judders when they are brought to the service depot's. We do not think it necessary to change all weak type axles indiscriminately unless further cases of failure occur. R/Lid.{A. J. Lidsey} | ||