I recently changed the front discs and pads (@33k miles) on my W204 C350 CDi, with genuine parts bought from my local dealer. It all was going fine, and with driver's side (R) done I started on the passenger side (L) when I noticed that the inner pad seems to be handed, as this photo shows: Realising my mistake I compared the original pad with the new pad and the only part that looked asymmetric is the backing material and the fact that it has an "L" on the back. So I carried on, and figured if they squeal I'd swap them over, but they are silent. Today, about 300 miles later, the car is in for a service at MB and they pick up that the pads are in the wrong way round. Again, it's no drama for me to change them but I've never had handed brake pads before. The wear sensor fits fine with the pad on the "wrong" side so it's not that. So what is the reason for them to be like that? Anybody know?