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).
The performance and failure analysis of two Michelin Pilote special silent tyres.
| Identifier | ExFiles\Box 146\5\ scan0134 | |
| Date | 19th April 1939 | |
| W/P - Sr. c. to Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} 1245 + 400b. Rm{William Robotham - Chief Engineer}/IMW.{Ivan M. Waller - Head of Chateauroux}10/JH.19.4.39. We are sending to you at Levallois two Michelin Pilote special silent tyres run on 8.B.V. in France. The damaged one failed at maximum speed on a straight road after 3072 miles on the offside rear. The other ran 4448 miles on the nearside rear. The side of the tread which has worn smooth is the inside i.e. towards the centre of the car. Both tyres were fitted at the same time and were run together. The mileage included 300 miles of high speed running on the Italian Autostrada, the longest stretch without a halt being one hour. About 800 miles were covered between the last Autostrada run and the failure. The tyres were good for non skid cornering and silence. We were able to use Snow chains but they occasionally hit the body brackets and wing edges and the fixing clips were ultimately broken. The layout of the steering does not at present permit us to use these tyres on the front. Rm{William Robotham - Chief Engineer}/IMW.{Ivan M. Waller - Head of Chateauroux} | ||