Only 3! The rolls drop even when not colliding! ;)
Really cool storm effect in some tries!
Viewing post in Hoarder's Nightmare jam comments
But the collision shape on the cart are very primitive, so there is a very less possibility of rolls falling off the cart because of collision error.
Actually cart is physics simulated and with increase in no of rolls i.e. increase in weight, its handling becomes more difficult. So if you have carried like 40/50 rolls and move fast and collide it will drop. If you are playing on PC, there is a slo-mo mode (toggle Z) that will help you avoid narrow obstacles. Change your max speed with scroll. And if your cart is full, avoid shooting, as it can shake your cart and make rolls fall.