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).
Testing of low pressure tyres on Phantom models and their effect on steering performance.
| Identifier | ExFiles\Box 17\3\ Scan107 | |
| Date | 6th October 1926 | |
| To B.J. from Hs.{Lord Ernest Hives - Chair} c. to R.{Sir Henry Royce} c. to Wor.{Arthur Wormald - General Works Manager} c. to BY.{R.W. Bailey - Chief Engineer} c. to PN.{Mr Northey} x7430 Hs{Lord Ernest Hives - Chair}2/LG6.10.26. x4565 x8430 LOW PRESSURE TYRES ON PHANTOMS. Replying to BJ1/E23.9.26. The steering on 8-EX car was identical to that fitted to 12-EX except for one modification and that is, on 12-EX car we had arranged a suitable amount of friction to damp out small oscillations of the wheel. The arrangement we fitted to 12-EX was only a temporary experimental rig-up, but WW. are preparing designs from which we expect to get the same effect by means of a hydraulic damper on the steering. We made a point of testing 8-EX car as it was received from London. The first thing we found on the car was that the tyre pressures varied from 24 to 38 lbs/sq.in. When we come to low pressure tyres it is more essential than ever that tyres should be run at the correct pressure. After we had adjusted the tyre pressures to 35 lbs. all round we tried 8-EX car and compared it with the present standard production. With either low pressure or standard 5" section tyres, 8-EX steering was better than the present average production cars which we are turning out. We carried out special tests in France and we have confirmed the tests in England and we do not agree that low pressure tyres increase the tendency for road shocks felt on the wheel. We do not think we can ever expect to get the same steering on a heavy double-limousine car such as 8-EX, as we can obtain on an open touring car such as 12-EX. As regards preparing 8-EX car for further trial by PN.{Mr Northey} We can either arrange a certain amount of friction in the steering such as we fitted to 12-EX, but as we have previously stated the scheme we have is not considered permanent, or we can fit a temporary hydraulic damper to the steering wheel which we anticipate will give similar results to the one which is being designed at WW. If the standardisation of the low pressure tyres is going to be held up until this test is made, it would appear that the temporary damper might be the best arrangement for PN.{Mr Northey} to try. As regards the mileage of low pressure tyres. We have 6.75" tyres which have run 5000 to 6000 miles on Expl: cars in England. In France it was unfortunate that our running with low pressure tyres was done during the hot dry weather, contd :- | ||