I Have a set of XTR FC-M950 cranks from my old bike. I recently got a new bike with not so great cranks on it. I want to put my XTR cranks on it but they are 8 speed. What do I have to do to make them compatable with 9 speed. I read the 9 speed chain gets caught between the chainrings on the fc-m950 8 speed chainrings.Any comments would be appreciated