Where to place jack to change tire on Toy Haulers?

Frame.

With a triple axle, I only let Discount do 1 side at a time.
When you jack up both sides on a triple axle, the middle axle does weird stuff and flips the shackles around.
Most 16 year old kids at tire shops don't know how to handle that, so I tell them to only do 1 side at a time.
Dual axle, lift the whole trailer at once, no problem there.