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).
Listing the weights of various tyres and wheel combinations.
| Identifier | ExFiles\Box 45\2\ Scan037 | |
| Date | 18th August 1927 guessed | |
| X4050 WEIGHT OF TYRES. K3725 / 720 31 X 6.00 tyre fitted on 19" wheel. 57 lbs. 5 1/4" tyre fitted on 21" wheel. 59 lbs. 33 X 6.75" tyre fitted on 21" wheel. 73 lbs. --------- | ||