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).
From Detroit discussing Chevrolet's suspension systems, associated costs and technical issues.
| Identifier | ExFiles\Box 173\4\ img073 | |
| Date | 18th November 1935 | |
| COPY. (Memo.from Ba.) DETROIT. 18. November, 1935. To E.{Mr Elliott - Chief Engineer} from Ba. We have had a discussion to-day with Olley and Fraser, the latter being the chassis engineer of Chevrolets. Fraser has confirmed what Olley has previously told us about the Dubonnet suspension. They are in serious trouble withit, due to cost, weight and accuracy of car control. They would undoubtedly scrap it now in favour of a wish-bone scheme if they had not spent £3,000,000 on tools and equipment for their present scheme, a fact which weighs with their administration. To make it acceptable they require another £1,300,000 equipment only, while to produce a wish-bone torsion bar scheme such as they are thinking of, requires £880,000 including tools, which the other does not. Cost lies very largely in the very great accuracy of machining they find to be necessary. Car control :- the lateral and torsional flexibility of the system, particularly with reference to the main suspension lever. They say they get a better steering car by shortening the suspension lever to 3 ins., the improved lateral and torsional rigidity of this lever off-setting any disadvantage arising from the short control arms. They did not show us the torsion bar schemes they are thinking of, but I understand it to be a wish-bone scheme with a very short torsion bar on the upper wish-bone. I do not know how they make the short torsion bar work, but hope to see the scheme before we leave. They use needle bearings in the main suspension lever for the steering pivots, and have found it necessary to burnish the races to a mirror-like finish. I believe we do not burnish our races. They make the very heavily loaded bearings on the pivot of the main lever stand up largely by this means. Shuddering of the front end is one of the difficulties they have encountered due to the flexibility of the front suspension, and also oversteering. They have no difficulties with steering joggles, but so far we have not been able to get any information | ||