Photograph comparing two different tire tread patterns.
| Identifier | ExFiles\Box 157\1\ scan0009 | |
| Date | 1st February 1932 guessed | |
| MP 1 17A2 20 | ||
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).