Garage door is closing roughly

During travel my door is not moving evenly first one side then the other will get caught up almost like the door is walking along the track. It is worse when the door is closing. It looks like if I were to put spacers on the top rollers to keep the door from.sliding back and forth it should help. However I can't find any kind of spacer or anything along those lines. This leads me to believe that this isn't the solution I need. I realize I could use washers if this was the case but I want to make sure that I fix the issue not just hide it.