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 wobbles caused by tyres running out of truth.
| Identifier | WestWitteringFiles\N\July1925-September1925\ Scan249 | |
| Date | 16th September 1925 | |
| R.R. 493A (50 H) (D.D. 31, 12-6-25) J.H.D. EXPERIMENTAL REPORT. Expl. No. REF: Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}/L.G16.9.25. C HIGH SPEED STEERING WOBBLES. +4565 / x457 To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to CJ. BJ. c. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c. to DA.{Bernard Day - Chassis Design} EY. c. to Wor.{Arthur Wormald - General Works Manager} We have confirmed the fact that if the tyre runs out of truth a wobble will be set up although the wheels are statically in balance. We did this by selecting from a number of 6.75" balloon tyres, two tyres, which when run on the axle only caused the spring seat to rise .015". We could not get a wobble out of this pair of tyres. We then repeated the test with two tyres which varied .050" / .060" and we were able to produce wobbles. The measurement of the tyre running out of truth was carried out as indicated in our previous report. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||