The Robits Mecanum Chassis is a fast and simple method to get a mecanum drive robot moving. This chassis allows for omnidirectional movement to help drivers quickly and efficiently maneuver any obstacles in their way. The chassis has a large opening which is perfect for mounting mechanisms and other components that might need to pass through your robot. There are few configurations available but if you are not sure what to get, we recommend am-5635_3B14. This version features our newest BB mecanum wheels which take up less space and provide a comfortable driving speed level. Wheels 3 or 4 in. BB Mecanum Wheels These wheels are our thinnest mecanum wheels The ball bearings inside of the rollers make for a smoother ride Motors NeveRest Hex 13.7:1 For a faster drive train, the 14:1 output of these motors is preferred We recommend this option when paired with a 3 inch wheel NeveRest Hex 19.2:1 These motors can handle moving around more weight at a more consistent speed We recommend this option when paired with a 4 inch wheel