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 pressure maintenance, user behaviour, and the performance of cord versus fabric tyres.
| Identifier | ExFiles\Box 39\2\ Scan123 | |
| Date | 14th November 1921 guessed | |
| - 3 - Messrs. Rolls-Royce, Ltd. such high pressures as we sometimes do recommend if we had any assurance that users would maintain uniform pressures. As you probably know, however, it is common practice for the average user to have his tyres inflated only periodically. Were he to maintain the pressure he specifies when he has his tyres inflated, he undoubtedly would get wonderful tyre mileage. Unfortunately, however, there is too great a tendency to permit the pressure to gradually get down to an unduly low point before he has the tyres again inflated. Then again, there are certain sections of the country where the road surfaces have become filled with potholes, and so forth. In such cases as these, even adequate inflation -- leaving out of the question undue inflation -- may cause certain cars of other than the best construction to either loosen and creak and rattle unpleasantly, or to ride so solidly as to cause bodily discomfort. In cases such as these, the user is inclined to run his tyres at disastrously low pressures "to save his car". When a tyre bursts, however, he does not remember all this, and immediately jumps to the conclusion that the tyre was an unsatisfactory one. You will agree that under such circumstances this may not necessarily be the case. Cord tyres of a given size, carrying a given load, may be operated with satisfactory results, we believe, at say not to exceed 10% lower pressure than fabric tyres of the same size and type, for the reason that the cord carcass construction (due to the absence of the cross threads of the close woven fabric construction) gives rise to less internal heat-creating | ||