Technical memo detailing the effects and specifications of fitting roll rods to a Bentley III.
| Identifier | ExFiles\Box 100\1\ scan0193 | |
| Date | 19th September 1938 | |
| To Da. {Bernard Day - Chassis Design} from Rm {William Robotham - Chief Engineer} /AFM. {Anthony F. Martindale} c. By. {R.W. Bailey - Chief Engineer} c. Da {Bernard Day - Chassis Design} /JB. c. HPS. {Horace Percy Smith - Experimental Factory Mgr} 446 Rm {William Robotham - Chief Engineer} /AFM. {Anthony F. Martindale} 10/MH. {M. Huckerby} 19.9.38. BENTLEY III ROLL RODS. With the 7" deflection rear springs and 8" deflection front springs it is necessary to have roll rods at each end of this car. A roll rod at the rear only would cause the car to over-steer violently, and a roll rod on the front only, of sufficient size to limit the roll to a reasonable figure, gives too much under-steer. The roll rod on the rear helps to prevent rear wheel hop and single wheel bump buffer impacts over potholes. We have fitted a roll rod to the rear of B.R.V., and the roll rate figures for the car are as follows:- Without roll rods. Front springs 138 lbs/in Rear springs 112 lbs/in With roll rods. Front 315 " Rear 147 " Roll rod stiffeners. Measured. Front (Oldsmobile rod) 177 " Rear 35 " Calculated figures (Da {Bernard Day - Chassis Design} /JB) Oldsmobile front on B.RV. 234 " B,III front 140 " Stiffness, Measured = 75% calculated The above rates are for 2" difference in wheel heights: the load is at the wheels. | ||
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).