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 table of rear axle particulars for Bentley, P.3, and Wraith models.
| Identifier | ExFiles\Box 154a\2\ scan0371 | |
| Date | 4th March 1937 guessed | |
| REAR AXLE PARTICULARS || BENTLEY | P. 3 | WRAITH | GEAR RATIO | 10/41 | 8/34 | 9/41 OR 8/37 | WEIGHT OF ASSEMBLY LESS BRAKES | 101 lbs | 196 lbs | | TRACK | 56" | 62" | 59" | TYRES AND WHEELS | 5.50 x 18 ON 3 1/4 RIM | 7 x 18 ON 5" RIM | 6 1/2 x 17 ON 4" RIM | AMOUNT OF HYPOID | 650 | 850 | 850 | 1.625 | CROWN WHEEL DIA. | 8.500 | 10.000 | 9.000 | HALF SHAFT DIA. | 1.000 | 1.250 OR 1.500 | 1.312 | ||