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).
High-speed steering wobble, its relation to tyre pressure and the effect of side steering tube springs.
| Identifier | ExFiles\Box 28\4\ Scan265 | |
| Date | 12th June 1925 | |
| R.R. 483A (50 H) (D.D. 31, 12-6-25) J.H.L. EXPERIMENTAL REPORT. -2- Expl. No. REF: Hs{Lord Ernest Hives - Chair}/Rml/LG12. 8.25. As an example, we obtained a wobble at 66 m.p.h. with a tyre pressure of 80 lbs. per sq.in. This wobble did not build up and was not violent. We then reduced the tyre pressure by 5 lbs. per sq.in. until we finally reached 35 lbs. per sq.in. High speed steering wobbles then took place between 59 and 48 m.p.h. The amplitude was very considerable, the car being almost completely out of control. In this latter case the wobble rapidly built up once it had commenced and continued on the overrun. At each reduction in tyre pressure there was a noticeable increase in the violence of the wobble. We have a number of experiments in hand in order to ascertain the fundamental cause of high speed steering wobbles. We find that side steering tube springs of reduced rating have a marked effect on high speed wobbles, preventing the latter building up. They also reduce the effect of the wobbles on the steering wheel so that the driver is much less sensible that these are taking place. We have, of course, previously experienced trouble with weak side steering tube springs which tend to promote low speed wobbles. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||