Propstands help maintain the integrity of the trailer chassis by supporting it during loading and unloading and they should be used even if the trailer is still coupled to a vehicle. Payloads are not evenly distributed when loading occurs. When complete, loads should always be evenly distributed around the trailer to avoid snaking and pitching during transportation. Swivel-prop stands have the advantage over fixed-foot by finding a level on uneven ground.
Side winding jacks are specially designed so that they can lift a trailer safely, perhaps leveling it so that equipment on board can be run. They have large load-spreading feet, a powerful winding ratio and will resist horizontal loadings so that the trailer remains stable even with the wheels off the ground.