Glerc 20" Mountain Bike For Beginner - MarsSTURDY FRAMEThis all terrain mountain bike uses carbon steel frame and internal buried brake cables, which can greatly improve ride safety. Great Braking SystemDisc brakes allow for more precise and controlled, are more effective than rim brakes, help to keep safer when riding at high speeds, down slopes and in wet conditions. Wider Tires 20 x 2. 8 inch knobby mountain fat tires provide excellent stopping power and tons of traction in sand and snow.