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).
Paper discussing the limitations of pneumatic motor tyre design and the subsequent development of a more comfortable, large section tyre.
| Identifier | ExFiles\Box 53\2\ Scan038 | |
| Date | 21th August 1923 guessed | |
| 1. In February 1921 when I had the honour of reading a paper before this Institution on the Design and Manufacture of Pneumatic Motor Tyres, I summarised the limiting features which hampered the tyre designer as follows:- a.{Mr Adams}) Type and size of rims on to which the tyre is to fit. b) Competition to be met. c.) Loads to be carried. d.{John DeLooze - Company Secretary}) Clearance to be maintained. 2. In the discussion of my paper - Mr.O.D.North asked what I would do if unhampered. This set me thinking and as a consequence I began work on a range of tyres which - 1. Need not make use of standard rim diametrs or sections. 2. Must compete with standard tyres as regards cost. 3. Must take normal loads as carried today. 4. Must not materially alter clearances on standard chassis. 3. MAKE TYRES MORE PNEUMATIC. As the Pneumatic Tyre alone makes it possible to travel at high speeds on modern roads I sought for a type of tyre which would be MORE PNEUMATIC - would in effect allow of higher speeds on rough roads than it is comfortable or advisable to drive at with normal tyres. A normal tyre of a given cross section can be distorted in a vertical direction under static loads to about 15% to 20% of its effective depth without undue tendency to disintegration and without undue power losses. Beyond this amount of distortion there is a rapid reduction in durability and an undue loss of power together with an uncomfortable rolling tendency when run at speeds above say 30 miles an hr. Also when the distortion percentage increases the tyre lacks 'LIFE' and does not respond quickly to road irregularities. Therefore it is obvious that the feasible vertical distortion in a tyre varies as the sectional variation. I therefore sought for a large section tyre in order to get the maximum vertical displacement ( in effect "COMFORT") consistent with durability. An improved range of tyres to be successful must be a practical one as regards:- | ||