6000 lbs each, when rested on level concrete and the weight of the vehicle is straight down with no sideways vector.
Strong enough for an odd angle of deployment and movement of the vehicle whose other two wheels are still resting on springs?
Perhaps, perhaps not.
I have some treated 2x12's I snagged from a dumpster, one of them stacked 3 high with 45 degree cuts for easy rolling, but they are a pain to carry around and like to harbor insects.
Rear airbags allow me some ability to level side to side and front to back by changing PSI
