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).
Specification table for various front and rear suspension springs and damping setups.
| Identifier | ExFiles\Box 16\5\ Scan049 | |
| Date | 22th September 1931 guessed | |
| TYPE. FRONT OR REAR POUNDAGE UP DOWN HOLES NO. VALVES. DIA. EQUIV. AREA SQ. INS. REMARKS. CF-20 Front. 75 95 1 .031. .000755 20/25 HP. Standard Springs. Good all-round suspension with well lubricated springs. CR{Mr Cra???ster / Mr Chichester}-20 Rear. BF-20 Front. 90 115 2 .039 .00239 20/25 HP Low Rating Springs. Max. freedom suitable for town carriage and old ladies, etc. BR-20 Rear. 90 115 1 {.039 .031} .00314 BF-20A Front. 90 115 1 .044 .00152 20/25 HP. Low Rating Springs. Provides additional damping to improve riding at speed. BR-20A Rear. 90 115 2 .039 .00239 AF Front. 120 120 2 .031 .00151 Phantom I. Best combination for use with plated and grooved springs. AR-2 Rear. 80 100 2 .031 .00151 AR-5 Rear. 100 100 - NONE - Ph. II Provides additional damping to reduce bouncing, etc BF-5 Front 110 110 1 .039 .00119 Ph. II Low Rating Springs. Suitable for town carriage, old ladies and cars for U.S.A. BR-5 Rear 90 115 2 .039 .00239 BF-5A Front. 110 110 - NONE - Ph. II Low Rating Springs. Provides maximum damping to improve riding at speed. BR-5A Rear. 110 110 - NONE - Hd{Mr Hayward/Mr Huddy}/33. | ||