UniStrut clamped to I beam for under chassis storage

I like the Unistrut mount better than the beam clamp. If you decide to use the Unistrut, please use nylock nuts so the vibration doesn't cause it to come loose. That is why I would never use a beam clamp on a mobile application.


Fuel tank and water tanks under my trailer, which is supported by Unistrut. I welded the brackets onto the cross members when I was building the trailer, but I used nylock nuts on the bolts so that they don't come loose.

I have been studying on similar approaches, and have just about decided to simply drill and bolt through the bottom flange of the Ibeam with grade 8 hardware.

My concern with the methods above is that they are likely designed for static applications. Going down the road with load on them is a whole 'nother ball game.

Search for sewer hose storage and there are a few threads to look at with some ideas

Anyone do anything with this? I like the idea of putting my spare tire and some other storage under there. My trailer has tons of ground clearance.

Looks like a great idea. My 5er has lots of space underneath and I've eyed the Lippert system but not for $700. Hoping to see a DIY soon ;)

I'd be careful about welding on the newer tempered steel frames,they are not the same animal as a truck frame.

Properly installed they won't come off even if the clamp bolt falls out.
Used on opposite sides off the beam and they act as toe clamps.
Jamb nuts will make them bullet proof .
Good Luck, Mike

I used unistrut under my frame for water tanks, and gasoline tank. They work great, but I welded 2"x3/8" straps with 3/8" holes in them to mount to. By the way, make sure you use Nylock nuts so you don't have to worry about them coming loose.

I would stay away from Beam Clamps. They probably won't work well with vibration.

This is what I use to attach to my IBeam frame without drilling.
They come in different sizes with an assortment of threaded holes to bolt uni-strut.

I've seen an expensive Lippert under chassis storage system ($700+) where the entire rig is held to the frame via 2 small diameter bolts drilled through the I beam flange on each side.

But if you drilled the frame the same way, they would void the warranty.

I like your idea.