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).
Clearance issues with new 6.50 x 17 wheels and tyres on a Bentley chassis.
| Identifier | ExFiles\Box 158\1\ scan0141 | |
| Date | 28th October 1937 | |
| To EH. from (M/PD). 28.10.37. BENTLEY CHASSIS 6.50 x 17. The following points should be noted which require attention when we go into production with the new 6.50 x 17 wheels and tyres. We have had a pair of H.R. special snow chains made to suit these tyres and we give below a list of the places where fouling occurs and where we shall require increased clearance. (1) Snow chains fouls the side steering tube on O.S. of chassis. Chains also foul the shock damper arm on the near side. See memo from Rm.{William Robotham - Chief Engineer} (2) Front mudguard A minimum of 1.500" between the tyre and wing tip is required. The clearance between the tyre and wing on the front shaped portion of the mudguard should also be checked, and a minimum of 1.000" shown on the drawing. Increased clearance will also be required where the wings foul the tyres due to roll on corners. (3) Rear Mudguards. Difficulty is experienced in fitting and removing the wheel as the chains foul the edge of the wing valance, at the running board end, in some cases at the rear of the wing.(see attached photograph.- Hm.{Capt. W. Hallam - Head Repairs} and Hn.{F. C. Honeyman - Retail orders}'s copy. Once the wheel is in position, wing to mudguard clearance is O.K., but the wing width may have to be increased slightly to allow for the wider tyre. Other points for Hm.{Capt. W. Hallam - Head Repairs} and coachbuilders to note. (a) Spare wheel covers new size required. (b) Spare wheel hub requires packing to stand tyre off the body further. (c) Discs - new size required. The present jack as supplied will be suitable for jacking up with a fully deflated tyre, but is not small enough when the rim only is used. Jacking was done using the standard jacking pad position on the rear spring. | ||