An aggressive yet well rounded downhill and gravity tire with well spaced, partially hollow and siped tall knobs for extreme grip An aggressive yet well rounded downhill and gravity tire with well spaced, partially hollow and siped tall knobs for extreme grip RSR - Building on the impressive original, the new RSR compound is a dual layer tread rubber, with the soft RSR compound on top and the stiff SRC on bottom AEC - Using the same 3-piece Aramid inserts as the AGC casing, AEC omits the apex at the bead: for the same high level of puncture and cut resistance but without the added weight