To ride a SHAN or OKA with 26 wheels. With this hanger kit, the chain-stay becomes 7mm shorter and the bottom bracket 12mm higher. Absolutely necessary to keep a frame fun to ride with 26″ wheels without having your pedal hitting the ground due to a too low bottom bracket. Adaptor IS/PM for 180mm rotor included. For 12x142mm rear hub, comes with corresponding set of bolts.