I've been fighting this for a while:

My Magnum trailer has 5.5" I-beams. All of the trailer jacks I have found only fit up to 5" beams. The mounting hardware that comes with these obviously won't work, but the real problem is that the jack has holes at 5" which directly line up with the top and bottom of the I-beam.

Short of welding a plate to the side of the trailer (definitely an option), has anybody else encountered this issue and what did you do to remedy it?

Thanks OB!

Easy answer would be to call Magnum and get a replacement. Hopefully someone will be along shortly with a better answer.

Further clarification: Magnum rigs out their trailers with this plate. It is for Fulton jacks. This one is pretty rusty and I'm done with Fultons. Cannot cut the Fulton mount off the plate because that plate is not wide enough to bolt a new jack to.

Can you maybe go inside to outside or inside to inside to get 5"?

BCStalk said:

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Can you maybe go inside to outside or inside to inside to get 5"?

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I could, but then I'm drilling holes in the I-beam. Not ideal.

We use to sell some of our bay boats with this exact trailer and jack. Had the same issue.
Our fix was a flat piece of plate and welded two flat bars at the same dimensions as where the "C" is on that mount. The plate was large enough to mount the new jack swivel mount to it and we just drilled new holes in the flat bars to match those existing mounting holes.
Made it out of hot roll and spray cold galv on it.
Did I make sense? Pretty easy really Used 3/16 plate and flat bar. Bead weld the flat bar to the plate on the outside Only so no welds to mess up fit to your I beam in the inside.

Would add that we would grind the corners round on the plate to make it look nice.

Gunny- Thanks, but I can't visualize exactly what you've described. I'm taking the trailer to a welder next week to get something like that done. I'll post a pic of the final product.

Gonna have to weld it. Having my own welders and fab gear makes this a non issue for me, but it is a real headache if you can't do the cutting and welding. The zinc spray will work for several years with several good coats.

I used to have a little Lincoln cracker box, but now I have to pay someone else. He does better work than me anyway.

Sorry man. The plate is about 6" square. The plate would be vertical reaching from the top to the bottom of the I beam but will be a little larger than your 5.5". The two flat bars will be welded horizontally on the back side of the plate so they will fit over the top and bottom of your I beam. Drill holes in both flat bars to match the holes from your existing mounting holes on the I beam.
You are basically making a modified C channel that will be slightly larger than your jack mount that will fit over the I beam similar to what you have now.
Make any better sense? Hope so.

Got it!

I'm leaving it up to the welder. We'll see what he comes up with.