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).
Car suspension and ride comfort, discussing tyres, cushions, shock dampers, and road springs.
| Identifier | WestWitteringFiles\O\January1926-March1926\ Scan131 | |
| Date | 13th March 1926 guessed | |
| (2) must supply something different, the better. I am definitely of the opinion that in my experience here the cars are, all things considered, much safer with semi-balloon tyres than with the ordinary high pressure, and that there is no more risk of high speed wobbles with them, and the steering is more pleasant. We almost always test up to over 70 MPH. when the roads are suitable, which is not often, but there is a suitable piece on our way to our market town of Hyeres. CUSHIONS. PN.{Mr Northey} when here spoke of cushions, and there is much to be said for Mr. Spinney's idea in the importance of damping these. I have noticed that the leather covered cushions in my semi-open 7-EX. may be considerably damped compared with textile cushions of porous cloth, the air from which freely escapes. I think our experts should get together over every car that is complained of and find the cause, and whether any other car, or our 20HP., is better under the same circumstances. Also on the same section of road, and speed, (often slow speeds are worse) change (1) tyre pressure, (2) the type of tyres, (3) the shock damper - adjustment and hydraulic types - (4) road spring stiffness. A simple way is to make the most perfect car possible at the Works, of the same weight and after demonstrating this, change the parts one by one to the car complained of until there is nothing left but the coachwork; then report to CJ. and R.{Sir Henry Royce} Until this is done make no changes in the thickness of plates or initial camber, because unless something is wrong I cannot see any benefit can possibly be obtained, but be sure that we are supplying cars to run with the most flexible springs that are practically possible. (1) No make of car that I know of has more favourable road springing than ours. (2) Every car will bump on the buffers if care is not taken to drive suitably to the road conditions, and if the shock dampers are not effective, and it is no use trying to make the springs so stiff that this will not happen, so we must be very careful to have these flexible enough to permit of the shock dampers being tightened so as to effectively check the rebound, or else sea-sickness will follow. The experts should examine the car, perhaps in series of 2 at a time - HS{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer} to see if things are normal, and what they consider is wrong, DA{Bernard Day - Chassis Design}/HDY.{William Hardy} afterwards, and finally EV{Ivan Evernden - coachwork}/SP.{Mr Spinney} to see if it lies in the cushions. Apart from the roads I have always found it lies between hard tyres, too high pressure, and over stiff rear springs. R.{Sir Henry Royce} | ||