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 specifications for Standard and New Type Dunlop 21' rim wire wheels.
| Identifier | ExFiles\Box 71\2\ scan0211 | |
| Date | 13th April 1928 guessed | |
| y8840 STANDARD DUNLOP WIRE WHEEL 21" RIM. y3725 Weight 34½ lbs. Length of hub shell 8.70" NEW TYPE DUNLOP WIRE WHEEL 21" RIM. Weight 32 lbs. Length of hub shell 7.80" Rm.{William Robotham - Chief Engineer} | ||