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).
Letter concerning the performance and supply of 'soft' and 'hard' brake linings from Johns-Manville.
| Identifier | ExFiles\Box 26\4\ Scan394 | |
| Date | 13th June 1929 | |
| X3960 OY-8 June 13th, 1929. Mr. R.W.H. Bailey, Rolls Royce Ltd., Derby, England. c - Mr. Hives Dear Mr. Bailey: BRAKES Johns-Manville Linings In response to your cable we have instructed Johns-Manville to ship to you direct through Perry Ryer. 30 Front brake linings G-74250 "Hard" 30 Front brake linings G-74250 "Soft" 50 Rear brake linings G-74743 "Hard" 50 Rear brake linings G-74743 "Soft" The last notation refers to the two types of linings which we have been trying out. The "soft" is that originally supplied which seems particularly squeak-proof and appears satisfactory in every way especially in its treatment of the drums which soon come to a high polish. The "hard" lining was supplied by the makers in response to our information as to loading per square inch, which runs higher than most American cars. It is probably not quite as squeak-proof, but appears sufficiently so for practical use. 6000 miles on the soft linings indicates a probable life of 20,000 miles or so per set of linings. The hard linings have so far only run about 3000 miles, so we cannot say much about them. We find however that the linings work best without squeak dampers. We had a "grunt" when coming to rest, with the hard linings, which was immediately cured by removing the squeak dampers. -continued- | ||