Looking for your first Mountain bike and are ready to go on to the bike trails. Our Decathlon Rockrider ST100 Mountain Bike, 27.5", 21 Speed, Black, Small is a great entry bike that is comfortable, durable and safe. Our Mountain Bike is designed for your first bike ride in dry weather for up to 1hr:30 min. Our ST100 Mountain Bike has a total speeds of 21! With this bike's lightweight aluminum frame and 27.5'' tires on double-walled rims, you can easily get through any obstacle. Considering that you may need to transport or store your bike in a limited space (car trunk, porch, etc.), we have equipped it with a front-wheel quick release. The rear wheel of the bike has a fixing nut that reduces the risk of being stolen. To remove the rear wheel, you will need a wrench. To make sure that you are always comfortable, the frame with a raised position for a straight back, the 80 mm suspension, the exclusive ergonomic saddle in the shape of a hammock. Soft touch grips and a height adjustable stem Enjoy the comfort and durability of the ST 100 Mountain Bike. Lifetime warranty on the frame!