[JRTJH]

I have a 4 ton bottle jack that I use with a block of wood. I position the jack under the spring U-bolts and lift from there. While I have no issues with the recommendation to jack on the trailer frame, I find that with the frame 24" in the air, that to obtain enough lift to clear the tire at pavement level, the distance from the base of the jack to the frame is approaching 30-31". That height, in my opinion, is too much to remain stable. So, I prefer to life at the axle and keep it at 4-6".

As chuckster said, using the truck scissors jack will also work. The only reason I haven't used my truck jack is because it's behind the seat, in the OEM plastic bag and I've never needed it while on the road. At home, I find a 3 ton floor jack on the axle U-bolts works much faster than the small bottle jack, but it weighs a bit over 100 pounds, so I don't want to pack it in the cargo hold of the trailer. That's the reason for the small bottle jack.... Weight....