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 brake drum types, their maximum attainable temperatures, and their effect on car weight.
| Identifier | ExFiles\Box 85\1\ scan0070 | |
| Date | 16th April 1936 guessed | |
| X206 | Drum | Max. Temp. attainable on 4 1/2 litre Bentley. | Weight Increase of car. | |----------------------------------|-----------------------------------------------|---------------------------------| | Standard 12" Bentley. | 350°C. | 0 | | Aluminium | 200°C. | - 8 lbs. | | 14" Bentley. | 305°C. | + 26 lbs. | | 12" Bentley with helical ribs. | 200°C. | Increase of 2 rear drums + 7 lbs. | | ||