The rear brakes on my '15 SR are terribly noisy. I'm fairly certain it is the material of the pads that's the culprit. Looking at the EBC catalogue, it seems the rear pads for '15 SR are FA213 (organic), FA213V (semi sintered), and FA213HH (sintered):
http://ebcbrakes.com/Assets/ecatalogues/2016_USA_Motorcycle_Catalogue/USA_Motorcycle_Catalogue_2016.html#p=30I decided to give the organic FA213 pads a try, because organic pads are supposed to be the quietest and most gentle on the rotors (don't last as long and don't "bite" as strong as sintered, but have better "feel" supposedly):
http://smile.amazon.com/EBC-Brakes-FA213-Disc-Brake/dp/B006BVHD4I/ref=sr_1_2?ie=UTF8&qid=1463278781&sr=8-2&keywords=ebc+brake+pads+fa213Amazon says they do not fit the Zero, but I trust the EBC catalogue to be correct. Hope they fit and work better than stock. Will let you know how they turn out once I get them in a week or two and install them. For under $25 delivered, I think they are worth a try.
Feel free to reply with similar information, including parts numbers and sourcing, if you have other alternatives.
EDIT: photo attached of the retail package with the EBC FA213 pads that I received. I still have not installed them, so I can't confirm fit and performance yet. You can't tell from the attached photo, but they seem to have some copper-looking bits in them (that look silver-ish on the photo). No metal shims are included with these pads (and there are none on the bike either in the rear, only in the front).