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).
Springing chart for all 40/50 HP cars to determine the required spring poundage based on the vehicle's total weight.
| Identifier | ExFiles\Box 72\3\ scan0229 | |
| Date | 9th June 1922 | |
| SPRINGING CHART FOR ALL 40/50 HP. CARS. PRIOR TO F.W.B. INSTRUCTIONS FIRST OBTAIN THE TOTAL WEIGHT OF THE CAR WITH MAXIMUM LOAD AS PER INSTRUCTIONS BELOW. THIS IS TO INCLUDE CHASSIS, BODY, SPARES, & ACCESSORIES & THE MAXIMUM NUMBER OF PASSENGERS FOR WHICH SEATING ACCOMMODATION IS PROVIDED. WHEN GIVEN THE WEIGHT OF THE BODY, ADD TO THIS THE CHASSIS WEIGHT FOUND ON TABLE BELOW & ALLOW 300 LBS FOR SPARES & ACCESSORIES (WHICH COVERS TWO SPARE WHEELS OR RIMS). ALWAYS ALLOW 112 LBS FOR LUGGAGE (WHETHER SPECIFIED OR NOT) UNLESS LUGGAGE IN EXCESS OF THIS IS SPECIFIED. ALLOW 154 LBS FOR EACH PASSENGER. HAVING OBTAINED THE TOTAL MAXIMUM WEIGHT, FIND FROM THE CHART THE POUNDAGE OF THE NEAR SIDE SPRINGS. GENERALLY SPEAKING THE OFF SIDE FRONT SPRING WILL BE 25 TO 50 LBS HEAVIER THAN THE NEAR SIDE SPRING, & THE OFF SIDE REAR SPRING ABOUT 100 LBS HEAVIER THAN THE NEAR. BUT OF COURSE THESE FIGURES MAY BE MODIFIED TO SUIT CONDITIONS OF WEIGHT DISTRIBUTION. BOTH THE CHART & THE ABOVE REMARKS APPLY TO CANTILEVER REAR SPRINGS, BUT WHEN DEALING WITH ELLIPTICAL REAR SPRINGS (CHASSIS PRIOR TO 2100) TAKE HALF THE ABOVE POUNDAGES. THIS CHART IS INTENDED TO FORM A GENERAL GUIDE FOR AVERAGE CASES, BUT CERTAIN CASES SUCH AS VERY LIGHT TWO SEATER BODIES OR CARS HAVING EXCEPTIONAL LOAD DISTRIBUTION, OR CASES WHERE OWNER HAS HIS OWN IDEAS OF COMFORT, WILL ALWAYS REQUIRE SPECIAL CONSIDERATION & JUDGEMENT. CHART AXES & LABELS: X-AXIS: MAXIMUM TOTAL WEIGHT OF CAR COMPLETE WITH PASSENGERS AND LUGGAGE LEFT Y-AXIS: POUNDAGE OF SPRING NEAR REAR RIGHT Y-AXIS: POUNDAGE OF SPRING NEAR FRONT. ADD 50 LBS TO FRONT SPRINGS FOR POST WAR CHART CURVES LABELS: 539 to 1699, 1700 to 2099, 2100 to 2699, A TO H, J ONWARDS (POST WAR) TABLE: APPROX. CHASSIS WEIGHT SERIES | LBS 539 TO 799 | 2730 900 TO 1399 | 2800 1400 TO 1699 | 2870 1700 TO 1899 | 3040 1900 TO 2099 | 3070 2100 TO 2699 | 3110 A TO D | 3200 G TO H | 3270 POST WAR | 3450 TO 3500 STAMP: ROLLS ROYCE LIMITED, PRINT ROOM, 11 SEP 1924, DERBY. | ||