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 and safety of straight-sided Dunlop cord tyres and rims compared to other types.
| Identifier | ExFiles\Box 45\1\ Scan262 | |
| Date | 28th April 1922 | |
| BJ, from Hs.{Lord Ernest Hives - Chair} c. to H.{Arthur M. Hanbury - Head Complaints} c. to BY.{R.W. Bailey - Chief Engineer} c. to EP.{G. Eric Platford - Chief Quality Engineer} X4050 Hsl/LG28.4.22. STRAIGHT-SIDED DUNLOP CORD TYRES AND RIMS. X4050 X3602 We attach extract from our original report ref. Hsl/LG19.5.20 regarding the Goodyear demountable rim which is the type of rim used by Dunlops. It will be seen from this report that we made tests running with the deflated tyre up to 60 M.P.H. and although the detachable rim opened out at high speeds, we had not a case of it leaving the wheel. S-Goshawk-11 which has just completed over 10,000 miles running in France, was fitted with this type of rim and straight-sided tyres. On that car there was a very large number of punctures; as many as five, due to nails, was experienced in one days' run. Altogether, there must have been 40 or 50 punctures. In no case was any difficulty experienced. It is very difficult,on the Goshawk car, to tell when a tyre is flat. The only way one could tell was by the flapping of the demountable ring on the wheels. Everyone who has had experience with the running of the Goshawk in France, is absolutely enthusiastic as regards the advantages of the straight-sided rim and tyre over the Clincher pattern, both as regards - means of demounting the tyre and also as regards safety. At Le CanadelHenry Royce's French residence, a 40/50 chassis fitted with Dunlop clincher pattern wheels and Michelin tyres, blew the tyre off the wheel about 20 yds. from R's garage. The greater percentage of racing cars today are fitted with straight-sided tyres. On the racing cars they adopt extra precautions for preventing the detachable band leaving the wheel, but these extra safety devices add to the difficulty of demounting the tyre and experience has shown that for ordinary conditions they are not necessary. Hs.{Lord Ernest Hives - Chair} | ||