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).
Investigating the causes of wheel wobble, specifically testing out-of-balance forces and balloon tyre deflection.
| Identifier | WestWitteringFiles\N\July1925-September1925\ Scan243 | |
| Date | 15th September 1925 | |
| R.R. 493A (50 H) (D.D. 31, 12-6-25) J.H.D. EXPERIMENTAL REPORT. -2- Expl. No. REF: Hm{Capt. W. Hallam - Head Repairs}/Rm{William Robotham - Chief Engineer}2/LG15.9.25. INDICATOR. we had anticipated from the movement with the wheels running slowly which appeared to be about .250". We then compared this movement with that occasioned by an out of balance of 1 lb. at the rim running at the wobbling speed. We did this by spinning the wheels up on the drums, and then lifting them clear by means of a tackle attached to the frame to get rid of the movement due to the tyres on the drums. In spite of the fact that the axle had not the weight of the car on it to restrain its maximum movement, the motion due to the 1 lb. out of balance was very little greater than that due to the un-even running of the tyres. We therefore believe at present that the uneven deflection of the carcase of a balloon tyre is sufficient to start off the wobble in step with the wheel revs. though the wheel may be statically and dynamically in balance. (b) We were able to demonstrate conclusively that the force causing the wobble to be maintained is the reaction between the tyre and the road. We did this by rotating the drums until we set up a violent wobble, contd :- | ||