Diamondback Bicycles Overdrive ST Hardtail Mountain Bike, Green High quality aluminum hardtail frame is classic in mountain biking Shimano 3x8 shifters give you 24 speeds to choose from Suntour XCT fork delivers 100mm of suspension travel to get you through the bumps 27.5" wheels roll well over obstacles and offer quick handling Tektro Aires mechanical disc brakes help you stop in all conditions