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).
Tyre testing results, future plans, and related vehicle modifications for the 'Corniche' model.
Identifier | ExFiles\Box 97\3\ scan0191 | |
Date | 28th July 1939 | |
To. Rm.{William Robotham - Chief Engineer} c. Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} c. Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer} 4009 Châteauroux. 3/28.7.39. 14.B.V.- CORNICHE. TYRES. Thank you for your further memos re tyres. You will read in the Daily Report the remarkably good results obtained with the 7.00-16 Dunlop tyres on 5.1/2 rims all round. It has transferred a rather frightening motor car into one which inspires real confidence in driver and passengers. The uncontrolled darting about of the front, accompanied by oversteer through small angles, has to all ordinary standards disappeared. The cornering is superb and the car handles better than anything we have ever known before. The steering would not want to be any heavier nor the reactions on very bad roads any worse, so we do not intend to try the 7.50 tyres on 14.B. but will run them on 30.G. when they arrive. They would foul the front mudguards of the "Corniche" in any case. We intend to try the 5" rims in place of the 5.1/2" with the 7.00 tyres to see how much stability we loose. The former are at present running on Bertha with 7.00-16 Avons. One of these has just had a tread come loose although it was worn nearly smooth. We also intend to try the 6.50-16 Dunlop 4 ply Rayon tyres on 14.B. for stability and tread shedding at normal pressures, also the special 6.50-16 when they arrive. We think that you should hold up on your decision to standardise Avon tyres on the Corniche and also definitely instruct Van Voorens to enlarge the spare wheel compartment to take 7.00-16 Dunlop tyres and modify the rear wheel covers to suit. We are going to get them to modify our wheel covers next week as they require attention in any case, due to damage by treads thrown. They will also be able to touch in the scratches on the roof. The rear propellor shaft of the Corniche appears to be approximately .750" too long, so that the sliding joint is practically choc-a-bloc all the time. | ||