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).
Technical report on mitigating vehicle tramping and wet brake issues for existing and future cars.
| Identifier | ExFiles\Box 84\2\ scan0224 | |
| Date | 17th December 1934 | |
| -2- A second palliative is the Wilmot-Breeden stabilising bumper. This definitely reduces the tendency to tramp when used in connection with increased shock absorber loads. Reducing the front braking or the tendency for the front brakes to come on quickly opposes the tendency for tramping to start. Increasing the transverse moment of inertia of the axle or reducing its frequency by fitting larger tyres with lower pressures tends to cause tramping to come on at lower speeds. Future Cars. By moving the axle control out to the extremity of the axle as shown in the attached photograph, we have so far been able to eliminate tramping, even with front shock absorber loads as low as 30 lbs/sq.in. A new design is required for this, also confirmatory results on a number of cars. (2) Jaggers when coming to rest with the linings wet. Existing Cars. Ferodo Bonded Asbestos is slightly better than M.R. for wet jaggers, but is not a cure. Personally we are of the opinion that the improvement is not sufficient to warrant changing over on production. We are verifying this. Future Cars. We find after a number of tests that, contrary to our original results, moving the axle control out to the extremity of the axle as described in (1) is not a cure for this trouble. We have a water excluder which is much more efficient than anything we have previously tried and will keep water off the brakes when the car is washed in the normal way. | ||