Founded in 1991, Ningbo Sunrun Bicycle Co., ltd & Its branch company Ningbo Tongkin Technology Co., Ltd. are the professional manufacturer engaged in producing bicycle transmission system & brake system parts. The key products range include derailleur sets,freewheels, cassette sprocket, cassette hub, disc brake & V brake sets, Chainwheel & Crank set,Torque Sensor B.B sets, total 7 series and about 300 models.Keeping ahead of the industry, every member of Sunrun has reagarded the perfect quality as the life. By adopting advanced technique such as high precision cold-forging figuration. numerial-control processing and heat treatment, Sunrun creates the complete bicycle transmission system parts with Sunrun own characteristic. "Tongkin Technology, Intelligent Manufacture. Running bicycle world, Quality first! "