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).
Recommended tyre pressures and longevity for 20 HP chassis.
| Identifier | ExFiles\Box 39\1\ Scan106 | |
| Date | 28th May 1924 | |
| Y/1238 To EY. from Hs.{Lord Ernest Hives - Chair} Hs{Lord Ernest Hives - Chair}3/LG28.5.24. X3602 X3538 X1238 20 HP. CHASSIS TYRES. Referring to your BY28/H27.5.24. All our experimental covered cars are run with 45 lbs. in the front tyres and 50 lbs. pressure in the rear. All open cars are run with 40 lbs. in the front, and 45 lbs. in the rear. We have had no trouble at all with the tyres running with these pressures. We do not agree with 60 lbs. pressure at the rear of a 20 HP. car. When taking this matter up with Messrs. Dunlop you might point out to them that we have been running Rapson tyres on the 20 HP. car with 35 lbs. pressure at the front, and 45 lbs. pressure at the rear. These tyres have completed 14,000 miles on the front without any trouble or even a puncture. The rear tyres ran for 10,000 miles - they have since been re-treaded by the makers and have completed another 4,000 miles. We have not had any trouble with these tyres or even a puncture. The point we wish to impress upon Messrs. Dunlop is that we do not think it is necessary for tyres to be run at high pressures. Hs.{Lord Ernest Hives - Chair} | ||