A Hi-Lift jack is the WRONG tool to use to change a tire and I would NOT recommend using one...Even with a leaf sprung rig, you still have to lift it dangerously high in order to get the tire off the ground to change it...
The need to completely unload the axles before actual effectiveness takes place, is a challenge. Can be overcome...though the solution can have its own drawbacks.
Last year we were wheeling in western Kentucky's hill country. One chap had tried to straddle a fallen tree and got stuck. Picture a JK, pointed downhill, about 20 deg decline, straddling a telephone pole diagonally. Wet and slimy, he couldn't get his left-front tire over the pole.
By the time my brother and I walked up, the guides had been working with a hi-lift making repeated attempts to lift the jeep high enough to get some rocks under the wheel. Couldn't, because the the suspension kept unloading, leaving the tire on the ground. It really concerned me how they were lifting this thing to the jack's limit, with the jack reaching ~15 deg relative to ground, using a rounded rock to keep it sinking into the muck. I was just waiting for it to spit out the bottom with a fair amount of force.
Karl and I sort of eased in and got things moving. A lot of wheeling is application of common sense and leveraging what you have available. I asked if anyone had a ratcheting tie-down. Hooking to the upper spring perch, under the axle, and back up, was able to finally lift the jeep--and axle--to get some rocks under it. Otherwise, I think we'd still be there jacking the guys jeep up and down. pun intended.
Its the one thing that convinced me, if I get a hi-lift jack, always have a tie-down or two with me. As a motorcyclist, i've got a few anyway<g>.
