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 to Dunlop Rubber Co. regarding out-of-balance limits for 6' tyres on 20' rims.
| Identifier | ExFiles\Box 45\2\ Scan199 | |
| Date | 20th December 1929 | |
| X4050. Expl. Dept. Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}3/MJ. Dec. 20th. 1929. The Dunlop Rubber Co., Fort Dunlop, Erdington, BIRMINGHAM. Dear Sirs, OUT OF BALANCE OF 6" TYRES FOR 20" RIMS. We have tested the three tyres you have sent us and find that they are outside any limits with which we can deal. We have gone into the question of the manufacturing limit of out of balance with which we can cope, and find that we can increase it from 37 in. ozs., to 67 in. ozs., and with this we have reached the limit for the balance weights which we can fit to the wheel. We therefore agree that we can accept tyres up to 67 oz. ins. out of balance as soon as we have made provision for increasing our balance weights on the wheels. You will appreciate that the difficulty has largely originated because you have increased the section of the tyre and decreased the diameter of the rim by which the balance weight is affected. Yours faithfully, For Rolls-Royce Ltd. For the attention of Mr. Bond. | ||