Actually, I tried my CRC Gen X retainer (on manual, it is called Slotted capture insert)...and that fits perfectly with the SP1 steering hub....in fact, I think it has a tighter fit then the original one which I really like.
I am not sure we are both talking about the same parts....but I know my retainer on my old GEN X fits perfectly with a flat head screw driver to drive it in....I am not sure CRC made the aluminum version of that.
And I believed the latest model XTi used the same slotted capture insert...it looks the same from outside but I do not have one and I cannot say that for 100%....see below pic from CRC site.
