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).
Calculation sheet for the gear ratios of an 8 Litre Bentley.
| Identifier | ExFiles\Box 124\5\ scan0024 | |
| Date | 4th January 1932 | |
| 4. 1. 32. 8 LITRE BENTLEY. GEAR RATIOS. Effective Tyre circumference at 35 lbs/sq.in. = 105.5" Road wheel revs/mile = (1760 x 36) / 105.5 = 601 Top Gear 4 engine revs = 111.75 Engine revs/mile = (1760 X 36 X 4) / 111.75 = 2270 Top Gear Ratio = 2270 / 601 = 3.775 : 1 3rd. Gear 6 engine revs = 126.125" Engine revs/mile = (1760 X 36 X 6) / 126.125 = 3015 3rd Gear Ratio = 3015 / 601 = 5.01 : 1 2nd Gear 8 engine revs = 126.125" Engine revs/mile = (1760 X 36 X 8) / 126.125 = 4015 2nd. Gear Ratio. = 4015 / 601 = 6.69:1 1st. Gear 10 Engine revs = 87" Engine revs/mile = (1760 X 36 X 10) / 87 = 7275 1st Gear Ratio. = 7275 / 601 = 12.1:1 | ||