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).
Dunlop memo detailing the results of deflation tests on large tyres.
| Identifier | ExFiles\Box 53\3\ Scan074 | |
| Date | 17th October 1927 | |
| X4565 DUNLOP MEMO. FROM Test House, Fort Dunlop. TO Technical Director, Fort Dunlop. DEPOT. DEPOT. A 34 Ref:- SUBJECT. 17th October .1927. Yours..................... DEFLATION TESTS ON LARGE TYRES. Ours HL/HH. Rolls Royce (1). A 33 x 6.75 balloon tyre was fitted to a 5 x 21 W.B. rim on an E 2 Wire wheel using standard rim tape, and inflated to 40 lbs per sq. inch. The wheel was then fitted to the O.B. hub of Sunbeam "B". A deflator cap was fitted and the car attained a speed of 50 m.p.h. when the tyre became flat. As the tyre became quite deflated, the speed dropped to 40 m.p.h. At this speed a 3 mile give and take course was followed. After 3 miles, the tyre was in ribbons, the tube was bunched up inside the cover but this was still on its rim. The car was stopped and restarted twice without the cover leaving the rim. (2). The test was repeated using a 6" for 21" medium pressure tyre, with similar results. (3). The test was repeated with a 6" for 21" medium pressure tyre but this time the rim nut on the valve was screwed up tight to prevent the valve from being drawn inside the rim. After a run of 3 miles with the tyre flat and including one bad left hand bend taken at speed, the tyre was still on the rim and was less damaged than the previous tyres which had been run without this nut being in position. During the last test the rim tape was broken and came away from the wall and got caught on the brake drum, but was soon torn away again. H W Lowley Copy to - Mr.Hyde. | ||