I have two complete sets of Elixer's and one pair came with bronze backing and the second pair with grey - hence my original query. Both sets are the same age/type.
I didn't specify pads - one set I purchased for a bike upgrade the others came as standard on my Boardman. I suspect the grey pads on the Boardman are organic as they have worn whereas the others haven't.
Posts
Parktools :?:SheldonBrown
Snot green Canyon Nerve AM 8.0x