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).
Wheel revolutions per mile for various tyres on 20 HP and Phantom II models.
| Identifier | ExFiles\Box 50\4\ Scan330 | |
| Date | 2nd November 1929 | |
| X4308. To EFC. from Hs{Lord Ernest Hives - Chair}/AJL. Hs{Lord Ernest Hives - Chair}/AJL1/ADL2.11.29. In reply to EFC4/AD5.11.29. The road wheel revs. per mile using present tyres are as follows :- 20 HP. 660 revs/mile (6.00 - 19" Silent tread Fort Reinforced Dunlop Tyre). This is the only tyre used on the 20 HP. car at present. Phantom II. 608.7 revs/mile (33 x 6.75" Silent Tread Fort Reinforced Dunlop) This is the standard tyre. The following have been fitted at customers request but not on our recommendation, on Phantom II cars. 7 x 21" Goodyear Allweather tread on flat based wheel, revs. per mile = 595. 7 x 21" Fort Reinforced Triple Stud Tread Dunlop revs. per mile = 601. 7 x 21" India Balloon Silent centre tread. revs. per mile = 604. Hs{Lord Ernest Hives - Chair}/AJL. | ||