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).
Front tyre wear on the 31-EX model and recommendations for the proposed Wraith.
| Identifier | ExFiles\Box 157\1\ scan0272 | |
| Date | 13th January 1936 | |
| X 1332 To H.{Arthur M. Hanbury - Head Complaints} c. to Da.{Bernard Day - Chassis Design} c. to By.{R.W. Bailey - Chief Engineer} c. to Wor.{Arthur Wormald - General Works Manager} Hs{Lord Ernest Hives - Chair}/Les.12/KW.13.1.36. Front Tyre Wear - Ph.III. From the 10,000 miles report of 31-EX in France, we find that the front tyre wear is far greater on the inside edge. The reason for this appears to be the fact that the wheel angle changes from 1° outward at the top in the normal position to 4° inward on full bump. There are methods for obtaining more even tyre wear - (a) to start with, an increased wheel angle, (b) to reduce the change in wheel angle between the normal position and full bump. The former requires a new stub axle and yoke, whereas the latter only requires new top and bottom triangular levers and a new yoke, provided we are ready to accept the inch which has recently been added to the width of the rear wheel track, for the front wheels. We recommend that a scheme should be done for Ph.III to give similar leverage characteristics to that of the proposed Wraith, which would enable information to be gained concerning :- (a) The reduction of front tyre wear on the inside edge. (b) " " " " due to scrubbing. (c) The reduction of steering road shocks. (d) Wraith complete front suspension system. (e) The resulting reduction in height of roll centre. Hs{Lord Ernest Hives - Chair}/Les.{Ivan A. Leslie} | ||