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).
Graph of rolling resistance against speed for various tyre pressures.
| Identifier | ExFiles\Box 161\1\ scan0223 | |
| Date | 3rd October 1938 guessed | |
| ROLLING RESISTANCE LBS/TON SPEED M.P.H. 250 225 200 175 150 125 100 75 50 25 0 20 40 60 80 100 120 140 24 LBS/IN² 26 LBS/IN² 28 LBS/IN² 30 LBS/IN² 32 LBS/IN² 34 LBS/IN² 36 LBS/IN² | ||