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).
Comparison of tyre losses for different brands based on maximum speed and dynamometer results.
| Identifier | ExFiles\Box 158\2\ scan0020 | |
| Date | 17th May 1939 | |
| -6- Rm{William Robotham - Chief Engineer}/TAS.{T. Allan Swinden}15/JH.17.5.39. Tyre losses based on max. speed for 1 mile instead of lap speeds. Type of tyre. Max. speed for 1 mile. H.P. reqd. for wind-age. H.P. remain-ing for tyre loss. Tyre loss by dyno results. Michelin. 90.4 80.5 19.5 30. Avon. 89.3 77.5 22.5 33.5 Dunlop Racing. 93 87.5 12.5 14.5 Avon (Initial run) 88.24 75 25 39. It is possible that the maximum speeds in this latter table are more honest than lap speeds, since the members banking at Brooklands gives the effect of quite a considerable hill. If this is so, then in the light of present knowledge the tyre losses on the dyno drums would appear to be approximately 1.5 times those obtained on the road, when the tyres are at the makers specified pressures. Unfortunately this does not quite hold true with the racing tyres, and further work will have to be carried out before a definite pronouncement can be made. Rm{William Robotham - Chief Engineer}/T.A.Swinden. | ||