Punctures affect the running stability of motorcycles. In general, motorcycles cannot be ridden when a tire is punctured because no spare tire is available. Therefore, motorcycle users desire to prevent punctures. To meet this demand, Honda since the end of 1996 has been adopting a dual-structure-tube for small motorcycles, which has a puncture prevention function. This tube has been highly welcome to a lot of users: as is shown by the number of 1,000,000 or more such tubes already sold. The tube is composed of a chamber with puncture prevention liquid and a chamber of air. The puncture prevention liquid closes a hole even if a metal piece like a nail sticks into the liquid chamber located on the tire crown side, so the air leakage can be prevented. In a monitor test carried out in the Japanese market, it was confirmed that the tube has been decreasing punctures by about 90%. Now, a new type of tube with a puncture prevention function has been developed for large motorcycles. Its features consist of: (1) ability to adjust the tire balance; (2) ability to run even with a hole in the tube; and (3) ability to help prevent a shock puncture. In order to use a puncture prevention liquid also for large size tubes, the composition of the liquid material and the included fiber were reviewed. In this paper, the tube structure as well as the new puncture prevention liquid and its durability are described.
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