Thought it must be right with smooth side up only reason I was asking is because the rubbers between the plastic feet and the metal rail doesn’t sit perfectly (see image below) this cast a doubt into my mind.Hi, I’m no expert but previously I’ve owned Bragans ones and now have VW ones. On both the instructions said to place the spacer plate smooth side up & in fact certainly in my experience if I didn’t then the roof bar feet wouldn’t have had much of a stable surface to rest on. As the underside is mainly hollowed out. If that makes sense. ? I’m yet to refit my VW ones but now have the parts / bolts and nuts as set out in this thread.