At 5000 pounds each, the corner jacks have plenty of capacity. I have changed a tire using the corner jacks alone, but I'm not real comfortable doing it. They can seem a little wobbly as big semis blow by the trailer, and they can be extra-hard to crank up if they are gritty after their emergency trip to the edge of the roadway. My procedure (below) is simpler to do than to read about.
First, I carry a short 2-ton bottle jack, about $15 at Amazon and others. It needs to be short because after a blowout, the frame of the TM will be close to the ground. My bottle jack has a 7" collapsed height and a 6" lift range. It also has a 6" screw extension in the center.
I also carry several (at least 6) short pieces of 2x6 board, plus a hunk of 4x4 - each 12-18 inches long. These pieces are used primarily for leveling in the campground, so carrying takes no extra space, but be sure they are accessible when you are pulled over beside the road.
Don't forget that somewhere in this process, you will need to get the spare tire off its storage rack, and flopped on the ground next to the camper. I do this about midway through the jacking.
When it is time to remove the bad tire, put a piece of 2x6 on the ground under the frame ahead of the tire. Screw the bottle jack core down, and set it on the board under the frame (NEVER the axle!). If the TM is too close to the ground for the bottle jack to fit, use the stabilizer jacks to raise the TM a bit, until the jack can be placed. On the other hand, if the jack fits with space to spare, raise the screw core until it contacts the frame.
Pump up the bottle jack to its maximum height. With a 2-ton rating, pumping it is really easy - much easier than cranking the corner jacks under load. Most likely it will not be up far enough, so lower the stabilizers all the way to the ground, letting them support the weight of the trailer again. Lower and remove the bottle jack, screw the core down all the way, add 2 or 3 boards to the pile, re-insert the bottle jack, and pump it up all the way up again. Lower the stabilizers further, until they again support the weight of the trailer. If the trailer still isn't high enough, remove the bottle jack, screw down the core, put more boards in the pile, jack it again, and lower the stabilizers again. Don't use boards narrower than 6 inches, as the pile tends to get wobbly as it get higher on soft or uneven ground.
When you finally get almost to the height needed to remove the bad tire, use your lug wrench to loosen the lug nuts a turn or so. Then continue jacking, adding boards as needed to get high enough to pop on the fully-inflated spare tire.
Reverse the process on the way down - it is quick and easy because you now have an inflated tire on the TM.
I can change a tire in less than 10 minutes, from getting out the tools to driving away, using this sequence. The bottle jack makes it easy, and safe.
Bill
