To make certain the riser will work. Send them a email and request measurements of the 2 holes of each set of riser bolt holes. The riser caps (as I call them) are the caps on top of the risers. The only way they would not work would be if the holes on the risers do not have the same distance for the speed o. The only other problem would be if they are for a HD that has a 1/2 inch bolt that goes through the triple tree that connects the riser to the triple tree.