Rear hitch installation. Unusual frame

[jkwilson]

I’d like to add a rear hitch to my Grand Design Reflection 303RLS to mount a bike rack.

I dropped the coroplast this weekend to measure things and plan for the job. I had hoped to use the Curt 13703 mounted to the I-beam frame.

I learned that this trailer has a bit of an unusual configuration. The bumper is welded to two short box beams that are welded to the bottom of the I-beams. This results in the bumper sitting completely below the frame. Of more concern to me is the fact that the Curt hitch would end up with the receiver at the same level as the bumper.

So I maybe have about three options:

I could have a custom hitch fabricated that would drop the receiver below the bumper. I’m a little concerned it would end up too low since the bumper already extends 4” below the frame.

I could remove the bumper. This would require some cutting to finish the rear of the trailer and then the fabrication of a new hose store tube up front.

Finally I could install the Curt hitch far enough forward that I could attach a custom drawbar that would clear the bumper or weld a second receiver under the one on the hitch so a standard drawbar will work.

Thoughts, suggestions or criticisms?

[BarneyS]

nayther wrote:
Snip...
I'd post a photo but this site is a PITA to put photos up. PM me and I'll send you a photo.

Not really a PITA at all!
It is very easy to post pictures on our forums. One of our moderators, 1492, developed this photo posting app to post your pictures. It works for other internet sites also. There is no need to have a separate hosting site for your pictures in order to use it. It is also much easier to use than Photobucket used to be.

It is very simple to use.
1. Upload your picture from your computer to the app.
2. Copy the resulting URL.
3. Paste that URL into your post without ANY changes. No additions or deletions.

Your picture will then appear in your post and be properly sized for use on our forums.:) See this thread which is stuck at the top of this forum for more information. So simple even a caveman could do it! :B
Barney

[nayther]

i had a custom hitch made for mine, receiver is on top of the bumper, similar situation on how the bumper and frame are modified by the factory, plus I have the fold down rack, which I kept.

I'd post a photo but this site is a PITA to put photos up. PM me and I'll send you a photo.

[Itinerant1]

This is what I did for my Cameo to give you an idea. It's now 30k+ miles now with no issues. I used a 2" receiver.

[jkwilson]

goducks10 wrote:
Just a thought.

Why not install a fence post under the 5er? Or set one on top of the bumper. I have one on my 5er for my sewer hose and it's in my top 5 mods. Mines been under the 5er for 6 camping seasons and under a previous TT for 2 seasons.


If you do go the 2" receiver route you only have 3/4 left top and bottom on a 4" bumper. Thats why I was thinking about the 1-/14" receiver to give more material to work with. I would suggest at least an 1/8" thick plate. The bikes and rack aren't heavy but the up and down motion will put the most stress on the bumper.

Either way it sounds like a fun project.

I plan on the fence post upgrade along with this.

A concern I have is that the receiver might move differently from the bumper, and anchoring them together might cause some damage.

Because of the construction of the rear of the trailer, I'm thinking the drawbar may need a bit of length so I'd be more comfortable with a 2" bar.

I'm considering adding a couple of 1-1/4" receivers out to the sides to stabilize anything I might mount. I'm more concerned withe reducing twisting and bouncing than weight capacity.

Thanks again for your input. I'll get after it with a tape measure tonight and maybe I'll have a better picture.

[hornet28]

Rather than a 2 1/2" round hole make it a 2" square hole and use a hitch cover.

[goducks10]

Just a thought.

Why not install a fence post under the 5er? Or set one on top of the bumper. I have one on my 5er for my sewer hose and it's in my top 5 mods. Mines been under the 5er for 6 camping seasons and under a previous TT for 2 seasons.


If you do go the 2" receiver route you only have 3/4 left top and bottom on a 4" bumper. Thats why I was thinking about the 1-/14" receiver to give more material to work with. I would suggest at least an 1/8" thick plate. The bikes and rack aren't heavy but the up and down motion will put the most stress on the bumper.

Either way it sounds like a fun project.

[jkwilson]

goducks10 wrote:
With your bumper setup I would cut a square hole for a 1.25" receiver to fit in. Fab a 4"x6" plate with the same size hole for the rear of the bumper. Fab another 4"x12" plate for the front of the bumper with the same size hole.
Weld a 2"x2"x1.25 tube between the frame to accept the end of the 1.25" receiver. Insert the receiver thru the bumper, weld the plates to the bumper and the receiver. Weld the end of the receiver to the 2x2 tubing.
Most bike racks can use a 1-1/4" receiver.

So my current tentative plan takes this idea and builds on it a little.

If the bumper won't be usable as a hose carrier anyway, removing it or disabling it are the same thing from that perspective.

Since the "natural" (easiest installation) position of the hitch would place the opening of the receiver right at the back center of the bumper, I'm thinking of using your "hole in the bumper" idea with a little variation. I'd rather have the 2" drawbar, so I'll cut a 2-1/2" round hole through the center of the bumper. This way I can insert a 2" drawbar through the bumper into the receiver for my rack, and I can pull the drawbar out and just pop in a 2-1/2" plug to get my hose storage back with no appearance issues or loss of ground clearance.

Stupid, crazy, genius?:h

[goducks10]

With your bumper setup I would cut a square hole for a 1.25" receiver to fit in. Fab a 4"x6" plate with the same size hole for the rear of the bumper. Fab another 4"x12" plate for the front of the bumper with the same size hole.
Weld a 2"x2"x1.25 tube between the frame to accept the end of the 1.25" receiver. Insert the receiver thru the bumper, weld the plates to the bumper and the receiver. Weld the end of the receiver to the 2x2 tubing.
Most bike racks can use a 1-1/4" receiver.

[jkwilson]

Okay, after some measuring, note taking, head scratching and maybe a little nap under the back of the rig, I had a workable plan:

I’d grind the welds where the short sections of box beam attach to the frame. Get pieces that are 4” longer, rotate the bumper forward a quarter turn and weld it on top of the box beam. Measurements checked out and the Curt hitch would mount.

I slid out from under the rig and it all came to a halt. The power cord plug is just above the bumper!

Alternate plan Y: Take the bumper off and mount a sewer hose holder under the belly. Use the Curt hitch as envisioned. Only negative is that the tail light wiring passes through the frame in that area so I’ll have to reroute that.

Oh well!

[jkwilson]

I need to go measure some more to know what I've dealing with. I'm inclined to think I can install the Curt hitch and raise the bumper enough to clear it. Alternatively I can install a belly mounted hose holder and leave the bumper off. A couple of questions if anybody knows:

If I raise the bumper, it will require offset brackets to bring it back up to frame height. Is there a standard/usual/common bumper height? Looks to me from my Google adventure that most bumpers are mounted in line with the rear of the frame rails.

And speaking of the frame rails, is there any kind of bracing done on the end of them for units (this is a 5th wheel, BTW) that have hitches on them. I'm wondering if the rails need to be stabilized from twisting under loads on the hitch.

Thanks for the input so far.

[BB_TX]

I would be concerned about going below the bumper level due to possible tail drag over drive dips and uneven entry ways.

[hornet28]

Cut the bumper off and use custom made brackets made to set the bumper higher if possible. Integrity of the hitch is more important than the hose holder plus you won't lose ground clearance

[Bionic_Man]

Custom hitch. That is what I had done and it wasn't that expensive.

[CaLBaR]

My Reflection 297RSTS TT came with the hitch from the factory and no bumper. Not sure if that helps you at all but seems to me when they come from the factory with a hitch there is no bumper.

Rob