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).
Performance and noise levels of new Dunlop M.A.1 and M.A.2 tread tyres.
| Identifier | ExFiles\Box 157\1\ scan0029 | |
| Date | 14th April 1932 | |
| W/S. To C. From Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} x4050. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}3/MA.14.4.32. DUNLOP NEW TREAD TYRES. With reference to C.9/C.13.4.32., and C.8/C.12.4.32., all our experience has been on the M.A.1 tyre, a photograph of which we attach. We consider these tyres to be a good compromise, and if you want to change from the silent tread, we suggest that this is the tyre to have. If they are really noisy on your trials cars you will have to turn them down for that reason, but our tests do not seem to agree very well. With regard to the M.A.2., tyre we have never had any of these for tests as they are only made in 21" size. Since the central rib is broken we should expect them to be more noisy than the M.A.1., tyre and we are somewhat mystified at the results obtained on Sg{Arthur F. Sidgreaves - MD}'s car. Perhaps you have the numbers of the treads transposed. The attached photograph gives the treads and what we belive to be their respective numbers. Hs{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer} | ||