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).
Blueprint graph of vehicle speed versus engine speed for various gears and tyre sizes.
| Identifier | ExFiles\Box 90a\3\ Scan073 | |
| Date | 12th June 1935 guessed | |
| E.R. HALLS CHASSIS R.P.M. AT 60 M.P.H. 5.50 x 18 TYRES TOP 2808 3RD 3244 2ND 4146 30 M.P.H. 1ST 2635 5.25 x 18 TYRES TOP 2887 3RD 3320 2ND 4240 30 M.P.H. 1ST 2695 TYRE CIRCUMFERENCE EFFECTIVE AT 35 LBS? 5.50 x 18 = 90.25" TYRE CIRCUMFERENCE EFFECTIVE AT 35 LBS? 5.25 x 18 = 88.25" ROAD WHEEL REVS/MILE 5.50" TYRES = 701.9 ROAD WHEEL REVS/MILE 5.25" TYRES = 717.79 AXLE RATIO 11 x 41 - 3.72:1 5.50" TYRES 5.25" TYRES Graph Labels: M.P.H. R.P.M. TOP 3RD 2ND 1ST F.D. | ||