Spank Spike Race Vibrocore Bars 800mm Wide 50mm Rise 31.8mm Clamp BlackSpank Spike Race Vibrocore Bars 800mm Wide 50mm Rise 31. 8mm Clamp Black. Spike Race Vibrocore HandlebarVibrocore is a low density low weight core that reduces frequency amplitude and duration of chatter from the trail 7 Series alloy with micro grain refinement during the drawing and extrusion process for a strong and light weight bar Dual Extreme Gradual taper technology (XGT) spreads the load out over a greater area of the bar to minimize breaks and