We are about to embark on another custom project, one of many we dream up because we have nothing better to do. We installed a Merrell hitch last fall and bought a storage platform from Harbor Freight to haul firewood and other dirty, bulky stuff. We are now fabricating a different receiver insert that will hold the platform but will also have a vertical bar welded to the insert so it extends upward just behind the spare tire that will then have another receiver at the top that will hold a bike rack. The plan is to use the platform and have a bike rack above it for 4 bikes or more. We would appreciate input as to the thickness of the steel tubing we plan to or should use.

The Harbor Freight platform insert is steel between 1/8 and 3/16 thick (seems to be just shy of 3/16). It's rated to hold 500 lbs. and many of you have previously stated you loaded it to just about that weight. We have purchase raw Curt receivers that we will use in the fabrication - they have 1/4 inch walls. We'd like to make the top receiver assembly height adjustable - it will slide down onto the vertical 2 inch tubing just behind the spare tire. Initial measurements call for the vertical piece to extend up to 18 inches or so above the bottom insert.

We have purchased a number of lengths of 2 inch tubing from a scrap yard, some is 1/4 thick, some 3/16. Is the 3/16 strong enough to use as the bottom insert that will hold the platform, vertical tubing, top receiver and bike rack or should we go with the 1/4 inch tubing for all of that? My son says go with the 1/4 inch as the weight difference isn't that much but I'm always concerned about a few pounds here and a few there, they add up. I also like the 3/16 inch tubing more as the corners are not as rounded as the 1/4 inch tubing.

Total weight of everything we might carry will vary but may be as much as 600 to 700 lbs. Is the Merrell hitch, coach (77 Kingsley), and this set up capable of carrying such a load?

One other question is the depth the bottom insert should or can go into the Merrell hitch receiver. The Merrell hitch receiver has quite a depth to it which most inserts don't penetrate fully. Would it be wise to untilize that entire depth/length with the bottom insert - is there a strength advantage by making the insert as long as possible?

I guess I might as well comment on the sway issue this contraption may incur. We're planning to use or make some type of tightening hitch locks to eliminate or minimize sway.

Thank you all for your input. If there's something else we're not contemplating please let us know that too.

Use the 2"x 2"x 1/4" wall tube for the width of the carrier and stab it in 12", that will do for the weight you mention.
Add a bracket that rests on top of the bumper, on the right and left front corner of the carrier
to minimize carrier twist.
When loading, load the heavy items in front and center of the carrier.
And a reminder that rear weight removes front weight, 700# on the rear removes about 500# from the front axle.

That should be more then adequate.