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 between two different types of tyre treads with technical specifications.
| Identifier | WestWitteringFiles\N\2October1925-December1925\ Scan9 | |
| Date | 20th October 1925 guessed | |
| COMPARISON BETWEEN DIFFERENT TYRE TREADS. (L) 33x5" TYRES 36 LBS / □" GROUND TAPER 2 LBS OUT OF BALANCE PIVOT LEANS 8° BACK .250 TOE IN FRONT 33 x 5" TYRES (K) FRONT 33 x 5" FLAT TOPPED GROUND TYRE 2 lbs OUT OF BALCE OTHERWISE AS L | ||