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).
Letter to Michelin Tyre Co Ltd. clarifying recommended tyre pressures for various car weights.
| Identifier | ExFiles\Box 39\2\ Scan102 | |
| Date | 15th October 1921 | |
| [STAMP: RECEIVED OCT 17 F C 21] ap6/DG15.1 sl. 15th October, 1921. Messrs. Michelin Tyre Co Ltd., 81 Fulham Road, Chelsea, S.W.3. Dear Sirs, We understand your mechanics have instructions to pump your Cord Tyres to 85 lbs per square inch when fitted to Rolls-Royce cars. We suggest there is some misunderstanding on this matter as the pressures we consider most satisfactory for Cord Tyres are:- (1). For light open touring car up to 44 cwt. - 45 to 50 lbs (2). For heavy touring car " 50 cwt. - 55 to 60 lbs (3). For Car over 50 cwt................. - 60 to 65 lbs Pressures above these result in a un comfortable riding which we should like the opportunity to demonstrate to you. Will you kindly let us hear from you on this matter. In the meantime our Experimental Dept., at Derby are running a car weighing 48 cwt., fitted with Michelin Cable Tyres pumped to 55 lbs. per square inch. We are, Yours faithfully, For Rolls-Royce Limited | ||