Brand New Mountain Bike 26" Model #148 D Mountain bike or mountain bicycle is a bicycle designed for off-road cycling. Mountain bikes share similarities with other bicycles, but incorporate features designed to enhance durability and performance in rough terrain. These typically include a enhanced front fork or full suspension, large knobby tires, more durable wheels, more powerful brakes, straight handlebars, and lower gear-ratios for climbing steep grades.  NOTE: This is no speed adjustment