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).
Suspension and tyre modifications for the 25-WJ Paris Trials Car for Continental touring.
| Identifier | ExFiles\Box 18\3\ Scan062 | |
| Date | 17th January 1930 | |
| To Ps. From Hs{Lord Ernest Hives - Chair}/sm. (Paris). x 7960. Hs{Lord Ernest Hives - Chair}/sm.S/WJ.17.1.30. 25-WJ. PARIS TRIALS CAR. With reference to your Psl/RJ.13.1.30. We quite agree that you may find this car insufficiently damp for high speed Continental touring. We are at the present moment with two cars in order to make them suitable for this class of work. This means different springs and friction shock absorbers in addition to the hydraulics. If the cars are successful you will undoubtedly be able to apply the scheme to your Continental Trials cars. For the present, we recommend that you put a 2 B.A. washer above the valve springs of the rear shock absorbers which should put up your poundage about 20 lbs. Our tests in France shewed that this was sufficient for anything except the worst roads at the highest speeds and though it does affect the low speed riding to a certain extent we are sure that you will find it preferable for Continental conditions. With regard to tyres. We have had complaints of the Silent Tread tyre from our London people and have made complaints ourselves. It is now established that the Buttress Striple Stud tread can be used where safety is put before silence. We are considering modifying the Silent Tread pattern slightly We have started the Dunlop Rubber Co., on a series of tests to find out what difference there is between various treads. | ||