JT Sprockets - Rear AlloyMade from the highest grade aluminium available: 7075 T6. Sourced from Austria, the 7075 T6 alloy comes off the same production line as the aluminium used in the Airbus planes. The heart of JT Sprockets and their durability, is the material used and the accuracy of the machining process. Every JT sprocket is made the right way, by hobbing, machining and drilling. This is the only way to achieve the closest tolerances and the best tooth profiles. And