Specification table detailing the particulars of low rating springs for 40/50 and 20 HP models.
| Identifier | ExFiles\Box 17\1\ Scan032 | |
| Date | 13th May 1931 guessed | |
| PARTICULARS OF LOW RATING SPRINGS. Length., Width., Top Leaf Thickness., Initial Deflection., Max. Bump Deflection. 40/50 Front, 45.0", 2.00", .257", 4.5", 6.250" 40/50 Rear, 66", 2.5", .265", 10.25", 14.1" 20 H.P. Front, 38", 1.75", .222, 4.0", 6.5" 20 H.P. Rear, 56.0", 2.25", .264", 6.4", 10.0" Free Camber., Loaded Camber., Buffer Clnce. 40/50 Front, 4.5" Pos., Flat., 1.750" 40/50 Rear, 10.25", Flat., 3.850" 20 H.P. Front, 4.5", .5" Pos., 2.45" 20 H.P. Rear, 5.9", .5" Neg., 3.625" | ||
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).