FSA chainrings-9 vs. 10 sp.
I have a 9 speed triple crank on our tandem mated to 10 sp Campy in the rear. It works fine but I want to change gearing with some smaller chainrings. Will 10 sp rings mount onto the crank the same?
You are leaving out a lot of info but I will guess..
If it is FSA crank it should have 130 mm bolt circle for the large and middle ring and 74 mm bolt circle for the granny ring. Should be the same as Shimano. Campy rings are 135 mm bolt circle for the large and middle and also 74 mm for the granny. You could use 10 speed Shimano rings or some other 9/10 aftermarket rings I am sure.
Here is a pile of FSA chain rings - lots 9/10 compatible.