I was curious why a lot of teams I have seen have two sets of rollers on each side of the robot. They have their main rollers, and then a small single sprocket roller on the bottom. Why are teams doing this.
The way I see it (and this could be totally wrong) is the first set of rollers are simply to pull the cube into the robot and align it while the second set do all the pulling power.
Read this post and thread here: