I have a alum I-beam Myco trailer with the torsional axles. Basically, I have to completely unload the suspension to get the tire off the ground. Don't think a bottle jack would have enough range to do the job unless I can get under the spindle like you were saying, and it would be VERY close to the tire.

Anyone ever use airbags to lift their trailer? Where are they be purchased?

Thing about torsion axles is they tend to hold the flat tire up, unlike spring axles. So, you can easily build a series of wooded blocks/ramps to pull your trailer up on, and move them around as needed to NOT support the flat tire. Then you can change that tire without using a jack.

Don't have any experience with air bags, but they would require compressed air to work. If you want to do the jacks, a couple of heavy jacks on one side of the trailer, pumped at the same time, would work. but not as safely as the wooden block approach.

Double ram bottle jack has almost 12" of lift. http://www.northerntool.com/shop/too...3v_xoCMGzw_wcB

The wood blocks would work under the right circumstances. If the surface was slick or had loose pebbles, it might be a pain. I have a couple of 2X12's nailed together with an offset so the tire only climbs one 2x12 at a time. Used them to raise the front wheels high enough so I could get my vette up on car ramps. Basically, they are car ramps to get on my car ramps. When I tried to use them on a concrete driveway, they just skidded. Wound up having to
place them against the small step-up where the driveway enters the garage.

I store and work on the boat in my shop that has a slick epoxy coated floor. I KNOW boards would slid around in there.

Found some air bags online. They have a 2500 lb capacity and only need 7 psi and raise from ~3 inches up to 22 inches.. One on each axle would do the trick for my rig..If connected together, they would raise at the same rate. I would probably need a 2x12 or something spanning across the axles so the bags would have a large/flat/smooth surface to press against. A big plus would be they work on just abt any surface; mud, soft soil, uneven surfaces, whatever. Another plus is I could use them in the shop where I have an air compressor.
A portable air tank (like an old bar-b-que propane tank or similar) pressurized to 120 psi would probably hold enough air to raise the trailer a couple of times. Humm, I think I just talked myself into trying them.

http://www.savatech.com/Towing/VLB.htm

BTW, I have no affiliation with any air bag manufacture.

Please report back after testing them. It's interesting.

I am in the same situation. What kind of jack to buy to change a flat on the side of the road? My boat on the trailer is 14000 lbs. I have a triple leaf spring Eagle trailer. The distance under the axle is 8" and under the frame is 20". I'm looking for something that I could possible keep in a storage box on the trailer, like a bottle jack. A floor jack is not out of the question, but a 3 ton steel floor jack is 70 lbs for $130 from Harbor Freight and their 3 ton aluminum floor jack is 51 lbs for $200. Any suggestions?

Wood platform works wonders. Loosen lug nuts before driving up platform though. Welcome mat to sit on while changing. Changed the flat (had two, same day) in 15 minutes. ( Carry two spares) I also have a bottle jack to put on the wood platform if necessary. Tried a floor jack once that I have for the truck, just no room to move handle up and down under the trailer.

I have 1 spare. Would like to get another cheap steel wheel or cheap aluminum wheel. The wheels I have now are 16.5" rims.

I have lifted the trailer from the frame, by building the wooden platform to set the bottle jack on, with a 6 ton bottle jack.

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