Stan's Flow MK4 27.5" Disc Rim. Features: Built on its storied history, the Flow MK4 continues the progression to make every ride better 30mm wide asymmetric rim designed to build an even stronger overall wheel (BST-Asymmetric) Bead Socket Technology Asymmetric features a wider inside rim cavity with shorter sidewalls, equalizing resistance to dents and tire bead retention on both sides of the rim in the worse rock gardens and hardest cornering WideRight: Provides the optimal volume without distorting the tread pattern or the side knobs so that they are in the correct position for cornering. Proper tire profiles not only allow for optimal tire performance but also allows the tire to do its secondary job of protecting the rim as well as the tire's sidewall Durable 6069 aluminum with a welded joint and reinforced spoke bed For use with standard tires or fully tubeless compatible with Stan's yellow tape and valve stems sold separately, use SX-806* and SX-812* Optimal WideRight tire sizing 2.3"-2.6" Specs: Size:27.5" Internal External:30/33.6mm Holes:28h ERD:561mm (3mm offset) Color:black/gray Weight:487g