Letter from a tyre manufacturer detailing performance specifications for a silent tyre.
| Identifier | ExFiles\Box 157\6\ scan0185 | |
| Date | 13th December 1937 | |
| 1339 INDIAProduction 20 HP. with 4-speed box and Front Wheel Brakes TYRE & RUBBER COMPANY, LTD. TELEPHONES: PAISLEY 4141/5 INCHINNAN SCOTLAND TELEGRAMS: INDIAProduction 20 HP. with 4-speed box and Front Wheel BrakesTYRE, RENFREW. OUR REF. PW/HDE. YOUR REF. Rm {William Robotham - Chief Engineer} /Gry. {Shadwell Grylls} 2/AP. 13th December, 1937. 7.8 fat S. H. {Arthur M. Hanbury - Head Complaints} Grylls Esq., Rolls-Royce Limited, DERBY. Dear Mr. Grylls, Further to your letter of December 8th, the 6.50/17 silent tyre has an inflation pressure of 28 lbs., load 10 cwt, effective standing radius 14.62", circumference 91.81", effective radius at 90 miles per hour 14.92", circumference at 90 miles per hour 93.697". The increase therefore works out at 2% on the 6.50/17 which is the same as the increase on the 5.50/18. Regarding a new tread design, we are working on several ideas but we are not in a position as yet to submit them to you. Yours faithfully, INDIAProduction 20 HP. with 4-speed box and Front Wheel Brakes TYRE & RUBBER COMPANY LIMITED. Pane horels. Works Manager. 6.50/17 At 60 mph 10/41 2810 rpm 10/43 2950 | ||
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).