ASP (Axle Stabilization Platform) is a custom chain tensioning system which stops axle slippage, what some riders complain about regarding their horizontal dropout frame. Most other "chain tensioners" only prevent the forward push on the axle with reference to the frame. This only fixes half the problem as it still leaves room for the backwards pulling movement of the axle. Just a slight slip in the axle equals an exponential change in regards to the rim and tire. This causes wheel misalignment, and in the end, can cause the tire to rub on the frame. The ASP tensioner prevents this as it fixes the tensioner to the frame eliminating both the pushing AND pulling forces on the axle. All 4 of FireEye's horizontal dropout frames, Spitfire XVI, Bloodshot, Shortfuse 360, and Shortfuse 380 use the ASP tensioning system.