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 test report for 7 x 20 tyres fitted to a Phantom Chassis.
| Identifier | ExFiles\Box 65\2\ scan0298 | |
| Date | 17th June 1929 | |
| X7820 Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer} from Mx.{John H Maddocks - Chief Proving Officer} Mx{John H Maddocks - Chief Proving Officer}4/T17.6.29 WHEELS WITH 7 x 20 TYRES. We have made a comparison test of a pair of wheels fitted with above tyres which you have supplied us for Phantom Chassis. The only thing we are able to notice on the road is, that the riding of the front of the car is better with these tyres, we have not noticed any adverse effect. There is not sufficient clearance for the cross steering tube leathers. Mx{John H Maddocks - Chief Proving Officer} | ||