Open Core Technology sounds like something you would find on a spaceship, well SRAM are not far off producing something just as state of the art with their SRAM Rival Crankset (inc GXP cups) 50/34. A crankset that balances weight with stiffness. The Open Core Technology (OCT), compared to conventional solid-core aluminium cranksets, is both lighter and stronger. The compact chainring setup features a 50 outside ring and pairs it with a 34 inner offering better easier performance on hills and climbs. The addition of GPX cups saves weight and makes for a smoother spinning system.