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).
Blueprint showing the dimensions and pattern of a 7.00' x 20' Dunlop Silent Tread Tyre.
| Identifier | ExFiles\Box 45\2\ Scan353 | |
| Date | 21th May 1931 guessed | |
| 7.00" x 20" DUNLOP SILENT TREAD TYRE. DEPTH OF TREAD .4375 .625 1.125 2.4375 4.00 4.9375 2.9375 THE DIMENSIONS OF THIS TREAD ARE THE SAME AS ON THE 7.00 x 21" SILENT TREAD TYRE, THE ONLY DIFFERENCE BEING IN THE TRANSVERSE GROOVES, WHICH CUT UP THE THREE CENTRE RINGS. IN THIS CASE THEY APPEAR TO BE CUT BY HAND, & ARE IRREGULAR IN LENGTH & HAVE RADIUSED ENDS. IN THE 7 x 21" TYRE THEY ARE MOULDED IN. | ||