Test data table correlating tyre pressure with vehicle speed and handling characteristics.
| Identifier | WestWitteringFiles\N\July1925-September1925\ Scan81 | |
| Date | 18th August 1925 guessed | |
| Tyre press: lbs/sq." | ADVANCE M.P.H. | RETARD. M.P.H. | TOE IN. | WHEEL BALANCE. | PIVOT LEAN. .125"/.150" | REMARKS. 60 | 66 | 66 | 1/2" | 1 lb. out. | * | Not very violent, fairly easily controlled. 55 | 65 to 68 | 68 to 66 / 63 to 60 | * | * | * | Intensity same as previous. 50 | 62 to 63 / 65 to 67 | 67 to 65 / 63 to 60 | * | * | * | Violent - just under control. 45 | 61 to 63/65 | 65 to 61 / 61 to 54 | * | * | * | Shade more violent than previous. 40 | 59 to 61 | 61 to 53 | * | * | * | Dangerous - still more violent than previous. 35 | 57 to 59 | 59 to 48 | * | * | * | Very dangerous. Hs {Lord Ernest Hives - Chair} /Fm. P | ||
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).