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).
Tests to ascertain if standard balloon tyres leave the well base rim when deflated.
| Identifier | ExFiles\Box 42\1\ Scan091 | |
| Date | 29th October 1927 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to BY.{R.W. Bailey - Chief Engineer} EP.{G. Eric Platford - Chief Quality Engineer} c. to MX.{John H Maddocks - Chief Proving Officer} Hm.{Capt. W. Hallam - Head Repairs} c. to OY. X3809 Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}/LG29.10.27. WELL BASED TYRES LEAVING THE RIM. X4565 We have been making some tests to ascertain whether our present standard 6.75" balloon tyre will leave the well base rim when deflated. We first of all carried out tests on 12-EX which consisted of skidding the rear of the car through between 90º and 180º with a rear tyre in various stages of deflation between 10 lbs/sq.in. and 0 lbs/sq.in. The road speed of the car was about 30 m.p.h. In no case did the tyre leave the rim until it was torn to shreds. Dunlops further, at our request, carried out a series of tests, a copy of which we attach. We paid a visit to their Works and they repeated test (1) for us. At the end of a 3 miles run with a flat tyre the cover had not left the rim although an inspection of it gave the impression that it might do so at any time, as a portion of the wired wedge was over-lapping the rim. However, judging by results, it does seem very difficult actually to make the cover leave the rim when driving forwards. We found that if we pulled the loose portion of the cover over the rim slightly after stopping in test (1), and then reversed the car slowly, the tyre would leave the rim, naturally after 3 miles flat the cover was somewhat dilapidated. Messrs. Dunlop agreed that this is one way in which they can make the tyre come off. contd :- | ||