Finally, a road bike for smaller riders! The GMC Denali 24" Wheel 21-Speed Road Bike is built around a lightweight aluminum road bike frame. The Denali Road Bike is equipped with alloy calipers and brake levers. The high-profile alloy Vitesse racing rims look as good as they perform. Shimano Revo shifters allow you to shift without taking your hands off the handle bars providing safety and confidence. A Shimano derailleur completes the drive train for quick and smooth gear changes. 14.75" Frame Size (measured center to center), 18.75" Effective Top Tube, 26.75" Stand Over Clearance at the center of the top tube, Alloy Rims, Steel Fork, Steel Crank, Alloy Caliper Brakes, Aluminum 6061 Frame, Alloy Water bottle Cage, Shimano Rear Deraileur, 24" x 1-3/8" Steel Bead Road Tires.