I think I am gonna build a chain bar for our mentorbot. can’t let the kids have all the fun.
From a statics point of view the axles on your motor should be long enough. However, I would sugest making them longer anyways.
Also, I noticed that you had to hold down the back of your robot in the video. How far forward is your center of gravity when you are lifting the sacks?
You will probably need to be especially careful when you are lifting and driving forward at the same time.
-Fido488
Yes I did have to 
We will be adding more weight in the back later on.
What’s driver practice for 