Spur Gears yog tus nqi siv hom iav .Lawv yog charcterze los ntawm cov hniav uas yog perpendicular o lub ntsej muag ntawm lub iav .Spur iav yog nyob deb ntawm cov feem ntau muaj, thiab feem ntau yog kim tshaj plaws .Qhov yooj yim piav qhia geomety rau ib tug spur iav yog qhia hauv daim duab hauv qab no.