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).
The performance of chassis 86-EE, discussing axle gearing, tyre pressures, wheel fittings, and standardisation of parts.
| Identifier | ExFiles\Box 47\1\ Scan114 | |
| Date | 9th March 1925 | |
| To N. from Hm.{Capt. W. Hallam - Head Repairs} C. to CJ. C. to BJ. C. to E.{Mr Elliott - Chief Engineer} C. to DA.{Bernard Day - Chassis Design} C. to BY.{R.W. Bailey - Chief Engineer} C. to BP. C. to Hs.{Lord Ernest Hives - Chair} C. to N. X4417 Hm{Capt. W. Hallam - Head Repairs}13/W9.3.25. 40/50 R-R.{Sir Henry Royce} Ch. No. 86-EE - Minchin. R12/M3.3.25. This car is a late 1920 model. It is fitted with a 16 tooth Axle. The difference in acceleration between a 16 and a 14 or 15 tooth Axle is very marked, and always gives us the impression that the higher geared Axle is less powerful. There is an enormous difference in the hill climbing performance between 14 and 16 tooth gears. Tyre Pressures. We find the difference between 70lbs. and 45lbs. pressure is enough to spoil the riding of a car, especially with Cord Tyres. We have included in our Instruction Book since 1922 the necessity for lower pressure. Cricklewood inform us that the Wheels for this car were despatched to the Dunlop Company who fitted new tyres and put in the pressure, and they were not interfered with by N. They did not test the car on it's own wheels and new tyres, the testing being done on loaned wheels and tyres. The car was taken away after it's own wheels and new tyres were fitted without further testing. We are asking N. to take up the matter with the Dunlop Company. Side Filler and Telegauge. We have a standard price for fitting these parts on all post-war cars which did not have them when new, and at customer's request we have fitted a large number on cars which have been brought in for repairs. Will Hs.{Lord Ernest Hives - Chair} please advise us regarding the standardisation of 7" semi-balloon tyres, and what changes are necessary to the wheels, wing clearance etc., to enable us to recommend them if possible to customers? Hm.{Capt. W. Hallam - Head Repairs} | ||