Skatecycle , Rock Skate board,Skate cycle , New skate board 1)Aluminum body ... exert to gain and maintain momentum on flat ground. Skatecycle , Rock Skate board,Skate cycle , New skate board,two wheel cycle ... different size crossbars?Currently there is only one size. Skatecycle , Rock Skate board,Skate cycle , New skate board,two wheel cycle