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).
Adoption of low-pressure tyres and suitable wheel sizes for the 20 HP car model.
| Identifier | ExFiles\Box 53\3\ Scan109 | |
| Date | 2nd July 1928 | |
| BJ. C. SG.{Arthur F. Sidgreaves - MD} from R.{Sir Henry Royce} c. to Hs.{Lord Ernest Hives - Chair} 4565 R3/M1 2.7.28. RE. PRESENT 20 HP. X.4565 AND LOW PRESSURE TYRES. X.527 X.5820 This car must have low pressure tyres (if not already done), or it will not compare with other makes. For years I have tried to get wheels and tyres of suitable size, somewhat smaller than present 21" rims (same as 40/50) and 6" tyres. Then we found Dunlops were departing from 21" as their only standard rim (heaven be praised) and had adopted 19", which is too small for our road clearance until we get India 3., which I have done my best to push forward, by making it a personal matter. Then the 19" rims and 6" tyres will be excellent - i.e. 31" wheels, (back axle gear OK) and low car. In the meantime pray Dunlops, Hs.{Lord Ernest Hives - Chair}, and everybody to agree and adopt the latest 20" X 6" tyres mentioned in BY2/G5.7.28 and DA{Bernard Day - Chassis Design}/EV{Ivan Evernden - coachwork}5/M11.7.28. R.{Sir Henry Royce} | ||