Semi Metal Resin Disc Brake Pads
Resin pads are made up of fibers and organic material that are bonded together with resin.
-Shorter break-in period
-More initial bite
-Prevent heat buildup
-Pushes heat back into the rotor
-Not as good in wet/muddy conditions
These pads are for lighter weight riders, and riding where lots of brakes are not required, like cross country, and riding in flatter areas. One thing I really love about the organic pads, is that they have a large amount of initial grab, this is a personal preference and you may not like this. When running these pads with smaller rotors, they will "manage" the heat better, meaning your oil is less likely to boil, which would cause a loss of power. Another great thing about resin pads is that they are much quieter, I know I hate brake squeal, and I'm sure you do too. One big disadvantage of these pads is that they wear out quicker, which means more replacing, and potentially more brake bleeds.
Sintered Disc Brake Pads
Sintered pads are made up of hardened metallic ingredients, which are bound together with pressure and temperature.
-fade at a higher temperature than resin pads
-better performance in wet conditions
-longer break-in time
-not as much initial bite
-heat is conducted through the caliper, not the rotor
These pads will be better if you are a heavier rider. These pads are recommended for riding in wet, muddy, or dusty conditions. They are also a lot better if you are running small rotors, or are on a long descend. Although they are more noisy, and do not have as much of an initial bite as organic pads, you will definitely notice the increased performance at the end of your run. This happens because the heat is put back through your caliper, rather than your disc where you would get brake fade. Since these pads are made of a harder compound they will last longer than resin pads, but do not buy these pads just because they last longer. Always buy the pad that will enhance your performance the best, they are cheap you can always buy more if they wear out.