Iíve been using Gibbs off and on for about ten years and I have a question. A friend of a friend wants be to make a rear sprocket for motorcycles. Does anyone know if there is a rule of thumb when making sprockets? The size is 9.43 dia with 46 teeth. I played with the GEAR generator but would like to know if there is a set formula or a rule of thumb that I should be using. The chain is a DID 520 , thanks for any help.