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).
Investigation into steering complaints and high-speed wobbles on the EAC-Vlll model.
| Identifier | WestWitteringFiles\P\2July1926-September1926\ Scan066 | |
| Date | 20th August 1926 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c.c. to BJ. Wor.{Arthur Wormald - General Works Manager} c.c. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c.c. to DA.{Bernard Day - Chassis Design} BY.{R.W. Bailey - Chief Engineer} c.c. to OY. ORIGINAL Hs{Lord Ernest Hives - Chair}/Rml/LG20.8.26. 12-EX - EAC-Vlll. X7430 X7450 STEERING. Our investigations on EAC-Vlll have shewn us that there were two main reasons for the complaints on this steering. (a) A complete set of Dunlop well base 6" tyres, which in their unworn state were bad for wobbles, and in addition wore unevenly, so becoming worse. (b) The exceptional freedom of the new axle. This emphasised road shocks and low speed wobbles and exaggerated the effect of high speed wobbles. (a) These tyres were some of the earliest of the type made by Messrs. Dunlop - we took them out to France some time ago. We tried a new pair with the car in its standard condition i.e. new axle, spring loaded cross steering tube, dampers 35 and 75 lbs. There was a distinct period of vibration on the steering wheel from 65 - 60 m.p.h. which was recognisable as a high speed wobble in embryo. Having the tendency to wobble, naturally these tyres are inclined to wear unevenly in sympathy with their periodic up and down movement. GWH.{George W. Hancock - Head Chateauroux} reports that they have worn 1/4 lb. out of balance in a day. It is obviously not much good re-balancing a wheel like this because the tyre will still be out of truth. We then tried some of the badly worn 6" tyres. With these the oscillation on the steering wheel was very much more pronounced and the period 58 - 65 m.p.h. The lightened front axle has clearly pushed up the period as with these tyres at 35 lbs/sq.in. we contd :- | ||