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).
Wheel arch clearance tests and solutions for brake and tyre fouling issues.
| Identifier | ExFiles\Box 14\8\ Scan170 | |
| Date | 1st October 1929 guessed | |
| -3- is obtained by cutting away the rear cushion ends locally. The car was then taken out on to a very rough field and driven over bumps and indentations up to 18" deep i.e. conditions which very few customers would tackle. Bad brake drum fouling occurred on the unaltered (n/s) wheel arch, whilst on the off side arch (modified) slight fouling occurred between the tyre and the wheel arch, (none on the brake drum), also the brake shoe fulcrum pin nut fouled the arch due to the arch being built out at this point about 1/4" over the edge of the subframe. Tests were carried out with no load, and with a full complement of passengers (6 up). We do not think it necessary to increase the clearance further to obviate the tyre from fouling, the foul is so slight that it is not heard, and the conditions necessary to produce it are very extreme, the brake drum is clear and further alteration means reducing seating accommodation. The fouling of the brake shoe fulcrum pin nuts can be overcome by stipulating that the wheel arch must not, at any point, overlap the edge of the subframe and by reducing the pins and using a thin nut and lock plate in place of the present castellated nut. As the rolling test is decided to be inadequate it would appear that the coachbuilders should have a template to work to indicating the clearance required at the centre line of the axle with a "car unloaded" buffer clearance (say 5.4") the template to be used, of course, with the wheel and tyre in position. | ||