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).
Comparison of driving performance before and after changing to lower-pressure Michelin 'Pilot' tyres, detailing significant improvements in handling and safety.
| Identifier | ExFiles\Box 146\1\ scan0074 | |
| Date | 25th October 1937 guessed | |
| - 6 - I will tell you. Let us suppose, then, that I am given a car with which I am unfamiliar, to try out, and it is equipped with a set of new tyres of the type fitted as standard and blown up to a pressure of 26 lbs. per square inch. I am to take it over a course that includes cambered roads with rough edges. On a bad road, the car is more or less impossible to hold: there is neither accuracy nor sense of safety. I must slow down when I pass a car, and I waste time when overtaking. The least surface irregularity throws the car about, with attendant discomfort for the passengers in the back. A sudden application of the brake makes the rear swing across the road... After the trial, the wheels are changed for the new Michelin wheels with "Pilot" tyres blown up to 20 lbs. per square inch. We start off again, and I have already realised the improvement by the time we have covered a bare dozen yards. It is a different car. If I had not actually seen the wheels changed, I should have thought that the shock absorbers had been readjusted - but no; as a matter of fact, no shock-absorber adjustment could possibly make all that difference. Now we are going all out at some 80 m.p.h., where before we were barely doing 45. I no longer have to hang on to the steering wheel like grim death, with eyes glued to the road. Driving and braking now feel perfectly safe, and I can pass and overtake without having to slow down. What before was a dangerous car now holds the road as well as the best designed racing car. Never, let me say, never should I have guessed that just changing the wheels could alter a car to this extent, and the | ||