I don't have any problems with piercings and riding. Of course all of mine are "north of the border", so... (9/16" lobes & 10g Conches)
I do know that my lobes get cold quicker than normal lobes. So take that into consideration, especially if they're stretched, and even more so if you're wearing eyelets/tunnels. (more surface area = colder faster)
+1 on all of the "below the belt" piercings