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).
Bentley clutch tests conducted on Porlock Hill, comparing wear between R.R. and Borg & Beck clutch types.
| Identifier | ExFiles\Box 129\2\ scan0124 | |
| Date | 25th November 1935 | |
| To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} X1110 Hs{Lord Ernest Hives - Chair}/FD.{Frank Dodd - Bodies}21/KW.25.11.35. Bentley Clutch Tests on Porlock Hill. We have carried out a series of tests on the above hill to determine the amount of clutch wear on the R.R. and Borg & Beck type clutches. Three cars were used, one fitted with the standard R.R. clutch, and two with Borg & Beck. All three cars were driven alternately by the Testers, so reducing any variation in the individual starts. The following results were obtained :- | Car and type of clutch | Pedal Movement at start from Works | Pedal Movement after 10 ascents, 3 starts per climb | Pedal Movement after 2 ascents, 10 starts per climb | Pedal Movement on return to Works. Distance 450 miles inc. Hill. | Total increase in pedal movement | Amount of wear on Clutch Lining | | :--- | :--- | :--- | :--- | :--- | :--- | :--- | | 1-B-IV. 10" Borg & Beck Clutch | 7.4" | 7.5" | 7.7" | 7.73" | .300" | .009" | | 3-B-IV. 11" Borg & Beck Clutch | 6.2" | 6.1" | 6.250" | 6.300" | .100" | .003" | | 4-B-IV. R.R. Clutch | 6.4" | 6.4" | 6.760" | 6.9" | .500" | .012" | Cars 1-B-IV and 4-B-IV were given a standing start on the 1 in 4 hairpin bend on Lynton Hill. Clutch pedal ratios were taken from Hs{Lord Ernest Hives - Chair}/Smth.9/KW.19.11.35. Hs{Lord Ernest Hives - Chair}/F.Dodd. | ||