When switching inner chainrings on your FC-M970 XTR chainset, use FC-M970 inner chainring fixing bolt – M8 x 10.1 mm (set 4) to do the job properly. New FC-M970 inner chainring fixing bolt – M8 x 10.1 mm (set 4) will mean a better fit for your new chainring and no chance of having to try to remove partially rounded or corroded bolts the next time you switch rings. Genuine Shimano replacement part