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).
High-speed steering wobbles caused by unbalanced Dunlop inner tubes.
| Identifier | ExFiles\Box 29\1\ Scan001 | |
| Date | 1st September 1925 | |
| No. 4657 BJ20/DN1.9.25. TO R.{Sir Henry Royce} c. to BY & Hs{Lord Ernest Hives - Chair} FROM BJ. HIGH SPEED STEERING WOBBLES. In R1/M22.8.25, you write as follows :- "Regarding the present chassis I think we are bound to issue these, and it appears that we are forced to use Dunlop tyres, in spite of their practice of constructing the inner tube by a scheme which naturally gives out of balance. At the same time I feel as though we ought to threaten them that we must seek another make of tyre if they insist upon sending out a design which produces an avoidable out of balance." In a memorandum written the same day (BY5/H22.8.25) BY wrote as follows :- "In connection with possible future changes, I attach herewith copy of a letter left with us by the Dunlop Company, from reading which it will be seen that the only change the Dunlop Company consider practicable from the foregoing is that they should balance the inner tube as a tube without the valve, which means that they would put a reinforcement piece opposite the valve of approximately 1 1/4 ounces, but they state definitely that the length of rubber necessary to balance the valve itself as well, that is, a further 3 1/4 ounces, makes it impracticable to try and add a sufficient length of rubber tube opposite the valve to accomplish this end. Mr. Paull definitely stated that no make of tyre was in balance. We have checked this, and find that whilst the Michelin Company do join the tube opposite the valve, and with a lapped joint, the valve and inner tube is still considerably out of balance, there being still approximately three ounces to balance as a part of the weight of the lapped joint on the tube is absorbed in balancing the reinforcement piece added to the tube at the valve seat." Kindly let us know whether you wish us, under the circumstances, to take any further action with The Dunlop Co. in regard to threatening them that we must seek another make of tyre. BJ. | ||