Thanks~After done my previous crawlers (Red and Black), I started to figure that if I could design a better one with more power. The key point is to make the front and rear suspensions rotate in a wider angle. From studying the solution of RC trucks, I found out that better design of links could make this happens, but where is the best position, you need to test many times until you find it. In my video, you could find out the Crawler in yellow has good performance in different terrains.