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).
New balance weights and imbalance limits for 7' tyres on 20' rims for the 40/50 model.
| Identifier | ExFiles\Box 65\2\ scan0321 | |
| Date | 5th June 1930 | |
| [Handwritten top left]: X7820 BY.{R.W. Bailey - Chief Engineer} From Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}4/MJ.5.6.30. [Handwritten top right]: X7820. X4050. X401. 7" TYRES FOR 20" RIMS. 40/50. The new balance weights on the 20" rim give a mass equivalent of 14 1/2 ozs. at the rim radius 8". We therefore consider that we could allow Messrs. Dunlops' a limit of at least 110 lbs.ins. [handwritten correction above: ozs] out of balance, and possibly slightly more, but the Test Dept. are giving us further information on this. We consider that it is worth while fixing a limit and checking covers separately when they come in, which could be done very rapidly and easily and save a lot of time when the tyres are fitted. It will also save covers and tubes having to be paired off to get balanced wheels, a practise which is of course undesirable from every point of view. We are satisfied that Messrs. Dunlops' are at the present moment giving us remarkably consistent tyres from the point of view of out of balance. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||