The Industry Nine Triad AL wheel runs an extruded 6069 aluminum rim with Hollow Bead construction, built to take the repeated hard hits enduro terrain throws at a wheel run after run. The extrusion process packs the alloy denser through the bead wall than a standard rim, so square-edge impacts and rock strikes don't leave a lasting dent. What Our Gearhead(R) Experts Are Saying:"I've cased a landing hard enough to hear the rim clip a rock underneath, and felt nothing but a solid thud instead of the ping of a dented wall. That's the extruded bead doing its job exactly when it matters."