Metal or resin comes down to how you ride and what conditions you ride in. The Shimano J04C uses a sintered metal compound that outlasts resin pads by a significant margin and maintains consistent stopping power when water, mud, and grit contaminate the braking surface. If you're burning through resin pads every few months or noticing your brakes fade on long descents, metal pads address both issues at once.

The sintered compound is made from metallic particles fused together under heat and pressure, which creates a harder friction material than the organic fibers used in resin pads. That hardness translates to longer wear life and better resistance to glazing when the pad surface gets hot. The trade-off is that metal pads can be noisier than resin, particularly in dry conditions when the rotor is clean. Most riders consider this an acceptable compromise given the durability gains, but if you're sensitive to brake noise, you may want to stick with resin for dry-weather riding.

Shimano added radiator fins to the J04C backing plate that work with Ice-Tech rotors to pull heat away from the braking surface. The fins extend above the caliper body and radiate heat into the surrounding air as you descend. This cooling effect reduces brake fade on sustained downhill runs and extends the temperature window where the pads perform consistently. The backing plate itself uses a composite construction with an alloy fin section bonded to a stainless steel pad carrier, which balances heat dissipation with the structural integrity needed to handle high braking forces.... Read More