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).
Difficulties and cost of fitting interchangeable balloon tyres on 20 HP and 40/50 HP chassis.
| Identifier | ExFiles\Box 53\3\ Scan046 | |
| Date | 1st April 1927 | |
| W/S. (struck through) c. to Hs.{Lord Ernest Hives - Chair} c. to E.P. (struck through) X4565 BY/29/G.1.4.27. RE FITTING 20 HP. and 40/50 HP. CHASSIS. INTERCHANGEABLE BALLOON TYRES ON EXISTING STRAIGHT SIDED WHEELS. Further to our memos BY1/G.25.3.27. and BY6/G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 25.3.27. in which we outlined the various difficulties which would be encountered in fitting the above tyres, the whole question has again received consideration, and in our opinion the cost of modifying the coachwork and the mudwings to give the necessary clearances would be considerably more than the cost of fitting wellbase wheels and tyres. This is the main objection to interchangeable tyres in the case of 40/50 HP. chassis, but on 20 HP. there are greater difficulties as pointed out in our BY6/G.25.3.27. Although we have increased the coachwork clear-ances specified on our chassis print which we are now issuing for new cars when fitted with wellbase rims and low pressure tyres, this alteration is not considered necessary in the case of existing cars. Hs.{Lord Ernest Hives - Chair} is in agreement with us that it would be cheaper and less complicated to recommend wellbase wheels rather than allow customers to fit interchangeable balloon tyres. BY.{R.W. Bailey - Chief Engineer} | ||