I'll generalize and go over the key[pun] points as I haven't got under a 1500 lately.
The torsion bar gives you travel by twisting and returning to static shape. The static shape[preloaded] gives the bar it's carrying capacity. When you load them up more by turning[adding more preload] you increase this capacity[like swapping a diesel spring in a 4.7 truck]. Yes it will sit higher but it will fight flex more as it has a greater ability to support weight[harsher stiff ride]. The torsion bar is hexed[sometimes threaded] at each end. The more you rotate one side, the more it tries to rotate the other. This rotation pushes the a-arms downward[the lift].
The key gets away with rotating one end and not as much on the other by changing the hex orientation[where the hex sits in correlation to the foot]. By doing so the preload is allowed to stay closer to normal setting and yet rotate enough at the other end to get the lift.
So in the simplist of terms, it's cranking without having to crank and suffer a stiffer ride.
Hope that helped [I think I left something out, working on no sleep for 2 days]
The torsion bar gives you travel by twisting and returning to static shape. The static shape[preloaded] gives the bar it's carrying capacity. When you load them up more by turning[adding more preload] you increase this capacity[like swapping a diesel spring in a 4.7 truck]. Yes it will sit higher but it will fight flex more as it has a greater ability to support weight[harsher stiff ride]. The torsion bar is hexed[sometimes threaded] at each end. The more you rotate one side, the more it tries to rotate the other. This rotation pushes the a-arms downward[the lift].
The key gets away with rotating one end and not as much on the other by changing the hex orientation[where the hex sits in correlation to the foot]. By doing so the preload is allowed to stay closer to normal setting and yet rotate enough at the other end to get the lift.
So in the simplist of terms, it's cranking without having to crank and suffer a stiffer ride.
Hope that helped [I think I left something out, working on no sleep for 2 days]