You could contact anderson directly and ask them, but common sense is telling me that if I use the anderson on one side (roll tire onto it) and then put the lower piece under the main piece to keep the tire elevated and level I must chock the wheel on the other side (in front and back) of tire so it wont roll anywhere when I take the camper off the TW. I use a similar leveler to the anderson but it doesnt have the two piece set up. However once I roll tire onto it and make the TT level, I have to lock my position per se by chocking tire on other side real tight or it would roll back off of leveler.