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).
Analysis of brake shoe wear, toggle adjustments, and a comparison of brake lining areas between the 20 HP, 40/50 HP, and Phantom models.
| Identifier | WestWitteringFiles\T\2July1929-December1929\ Scan116 | |
| Date | 6th November 1923 | |
| -4- Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}2/AD6.11.23 contd. thrown away on the side by side rear axle is .207. This corresponds roughly with the theoretical 5 notches wear at the shoe centre equalling .095". [Diagram showing measurements .312 and .125] Theoretically the rivet heads should not come in contact with the drums until .175 has been worn from the liners, but we may assume that .150 might actually be used could the toggles be adjusted. We believe that the original reason for preventing toggles being adjusted was to deter chauffeurs from running on the shoes after the old cast iron liners had been worn out. There does not seem any point in preventing depots adjusting the toggles now, provided the adjustment is limited, for by this means 50% more life could be obtained from the brakes before re-lining. Apart from this, however, we are better off for rear foot brake lining on the 20 HP. than the Phantom. 40/50 HP. 20 HP. Foot Rear 53.2 sq.in. 60.3sq.in. Foot Front 50.0 sq.in. 30.0 sq.in. Hand 53.2 sq.in. 38.0 sq.in. RECOMMENDATIONS. Existing Cars. That depots should be allowed to adjust the toggles within limits and that reduced direct braking | ||