Bicycle Tutor

Why?
I've seen this on replacement v-brake pads (i.e. just the pads that slide in). Then further on the packaging it states: "Warning! - use with ceramic rims only". Is it possibly something to do with wet weather riding..?

I think that "ceramic" rims have an extra hard coating on the braking surface. I assume you can then use a more abrasive brake pad for better stopping power. But if you use those pads on a normal alloy rim, it will wear away the metal of the rim much more rapidly than a normal pad.