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).
Chart and instructions for determining front spring poundage based on total car weight.
| Identifier | ExFiles\Box 178\1\ img204 | |
| Date | 28th August 1926 guessed | |
| 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 NEARSIDE 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 IDEA OF COMFORT, WILL ALWAYS REQUIRE SPECIAL CONSIDERATION & JUDGEMENT. Chart Axis Labels: Left Axis: POUNDAGE OF SPRING NEAR FRONT = PRE WAR. Right Axis: ADD 50 LBS. TO FRONT SPRINGS FOR POST WAR. Bottom Left (partial): GAGE. 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 2600 | 3110 A TO D | 3200 G TO H | 3270 POST WAR | 3450 TO 3560 | ||