A lightweight 6061 heat treated aluminum frame provides an excellent foundation. Shimano RS25 Shifters and TZ31 Derailleurs ensure a precise and crisp drivetrain. Lightweight alloy 29-Inch rims provide lower rotational weight compared to steel rims making the bike feel agile and easier to handle. 29 x 2.1 inch all terrain knobby tires provide great grip on any surface. The 170mm crank set with 28, 38, 48 tooth rings is made from steel for durability and strength. A quick release alloy seat post clamp provides tool-free seat height adjustment. Bike arrives 85 percent assembled. You will need to install the pedals, front wheel, handlebar and air up the tires. We recommend that you have your bike inspected for safety after assembling.