myredracer wrote:
We have a Torin double ram bottle jack that extends from 5 1/4" to 14" and fits under an axle even with a flat. It's compact and stored away under the bed.

Umm.. no. Not in my case.
Wished it wasn't so cold and snowy or I would take a photo.
Mine has drop axles, the axle tubes are much lower than the hubs putting the outside of the rim about 2" lower than the axle tubes when the tire is flat.
Even with the tires fully inflated, that jack would be a bit too high and I have to put it offset under the spring towards the spring mounts.
So, not everyone can get away with even a shorty bottle jack.
Which is why I mentioned low profile trolley jacks or even scissor jacks.
At home, I use a big floor jack under the trailer frame because of the drop axles, just makes the job easier.
Personally, you simply need to practice jacking to figure out what works and what doesn't. What works for one person may not work for another.
Sometimes like in my case, TWO jacks comes in handy, one taller bottle jack for jacking under the frame and a shorter bottle jack or even a scissor jack for under low clearance items like in my case..
My plan is to use the tall bottle jack under the frame to lift the axle high enough to get the short bottle jack under the axle.
Fortunately, I have not needed to try my plan.
Also, must be aware of how your trailer is setting, if you pull off on the berm, one side of the trailer will be heavily leaning.. This can create a dangerous position and trailers are darn heavy.. Jacking the high side with a heavy lean to the low side can be dangerous..
Same goes for having to jack the low side, extra weight will be shifted via COG (Center of Gravity) which can overload your jack..