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).
Joggle test results for various Marles steering gear configurations on a 21GIII (25HP) model.
| Identifier | ExFiles\Box 95\1\ scan0261 | |
| Date | 2nd January 1936 guessed | |
| Joggle Tests on RR Marles Steering on 21GIII (25H.P.) Note. No set up load. Table Header: Particulars of Steering Gear. | Turns of Snatchometer. Column Header: | 6 miles of poor road, @ 55 m.p.h. | 2 1/2 miles of rough road @ 45 m.p.h. Row 1: 6° 35' Helix Angle. Adamant parallel roller bearings on Cam and roller. Bedding of rollers on cam corrected. 8.250 pend. lever. | 10.73 | 4.62. Row 2: 6° 35' Helix angle. Timken bearings on Cam and roller. 8.250 pend. lever. | 8.37 | 4.34. Row 3: 5° 48' Helix angle. Timken bearings on Cam and roller. 9.437 pendulum lever. | 4.58 | 3.54. Row 4: 5° 48' Helix angle. Timken bearings on Cam and roller. 8.250 pend. lever. | 4.70 | 2.85. Section Header: Tests on Ph III 30 Ex. Row 5: Original Design of RR. marles gear. 6° 35' helix. Adamant bearings throughout. | 6.57 | 7.19. Row 6: La{L. A. Archer} Salle gear. | 1.94 | 1.70. | ||