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 pressures, steering stability, and wobbles.
| Identifier | ExFiles\Box 158\1\ scan0012 | |
| Date | 14th January 1927 guessed | |
| contd :- -4- amount of comfort. We find that this practice affects the steering in-so-much as it gives the car a feeling of instability at high speeds commonly called 'wandering'. In consequence we recommend that for cars that indulge in high speed work, the rear pressures should not be allowed to fall below - 33 X 5 high pressure tyres = 40 lbs/sq.in. 33 X 6.75 low " " = 30 " " (e) Balloon tyres and steering stability. Our experience is that balloon tyres on correctly designed axles do not affect the steering stability at speed. In a number of cases they have definitely improved cars having a tendency to wander. They slightly reduce steering shocks but make the steering considerably heavier for shunting and low speed work. (f) Large tyres and pressure increase due to increase in atmospheric and running temperature. It is not generally realised that the inflation pressures of balloon tyres changes very considerably with the temperature of the tyre. The 6.75" tyre at 35 lbs/sq.in. will rise as much as 6 lbs/sq.in. after a high speed run on a hot day. It is therefore recommended that tyre pressures should always be checked in the garage after the car has been standing some little time. (g) Low speed wobbles. Low speed wobbles depend for their generating power upon the reaction between the tyre and the road. For this reason, as with high speed wobbles, the tyre with the best non-skid tread is the worst for wobbles. contd :- | ||