| 摘要 |
A sprocket assembly is provided for a bicycle having a large sprocket and a small sprocket. The large sprocket includes one or more chain support projections formed on the side surface opposed to the small sprocket. Each projection includes a contact portion defming a contact surface for contacting, without meshing, a lower end of a chain shifted from the small sprocket to the large sprocket. The projections are arranged on the large sprocket with a size and shape that allows the projections to pass between outer links prior to the gear-changing operation. The chain support projections are arranged for causing the contact surface to contact the chain engaging the small sprocket and pick up the chain radially outwardly of the large sprocket during a chain shift from the small sprocket to the large sprocket.
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