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).
Comparison table of rod and lever arm specifications for Oldsmobile and Wraith III models.
| Identifier | ExFiles\Box 9\5\ 05-page152 | |
| Date | 29th December 1937 guessed | |
| Particulars. | Oldsmobile. | Wraith III. Dia. of Rod. | .6875 | .634 Effective Length. | 34.000 | 28.500 Lever arm. | 7.000 | 8.000 Lower triangle fulcrum lever length. | 14.250 | 12.350 Load at end of lever arm. | 1010 lbs. | 1020 lbs. Rate per inch at end of lever arm. | 164 | 193 Rate per inch corrected to Oldsmobile. | 164 | 193 x 12.350 / 14.250 = 167.500 Max. stress ( full bump rebound) | 108,500 | 105,500 Angular movement of roll rod arm. | 52° | 39 6° roll represents (angular movement of roll rod arm.) | 37° | 29° Torque at 6° roll. | 5,000 lb. | 6,075 lb. Stress at 6° roll ( torsional) | 77,300 | 78,500 Load at end of lever arm at 6° roll. | 720 | 760 Combined torsion - Bending stress at 6° roll. | 91,000 | 91,500 Max. bending at 6° roll. | 159,000 | 149,000 | ||