ADDING LUND TRUCK CHEST & SEWER HOSE STORAGE TO 14DB BUMPER

[GrampaKilt]

Above the 14DB bumper, the 39" space between the licence plate and fridge access grill fits a LUND aluminum truck chest (36"x20"x20") I purchased at Canadian Tire. I also wanted to include a common bumper mod–a 5"x5" vinyl fence post for sewer hose storage. The pictures show the design I came up with. Below are some specifics in case some are interested in trying this. For purchasing common related items, it seems 1-stop shopping is a foreign concept in Canada, so I'll include some component sourcing. PM me for further information about this project.

* to prevent overhang torque and provide a wider surface for the vinyl post, I glued (PL Premium) and lagged a pressure-treated 2x4 to the rear of the back bumper (ideally, one would weld on 2"x4" aluminum stock)
* ½" PT plywood was glued to underside of LUND chest to stiffen the sheet aluminum bottom
* for the frame, 1" square aluminum tube with 1/8" wall; the 8" brackets are SS (Cascade Manufacturing in Bellingham WA); 1/4" diameter SS bolts with locking nuts used throughout
* ½" space between trailer and chest; ¼"x¾" rubber bumper strip attached to top edge of chest just in case of contact
* square black plastic tube caps on order (good price from Home Hardware)
* vinyl fence post (Rona), cap (Home Depot), U-shaped vinyl gutter (Home Hardware); Home Depot USA stocks all three plus the LUND chest!
* LED strip (Amazon 'Partsam') at bottom edge of LUND chest is wired to the brake light (black, white is ground)
* see pic for the aluminum strap(s) that connect the rear bottom corners of the LUND chest to the trailer frame (note elongated carriage bolt hole for assembly adjustment)
* see pic for makeshift tool to insert and hold bolts/nuts anywhere inside the vinyl fence post
* see pic for yet another way to secure the vinyl post end cap (galvanized tent stake); the annoying trial and error task of inserting the stake in the second (bottom) hole solved by drilling out a funnel shaped guide in some solid nylon

[Steve Sanders]

Very nice!

I put a similar box on the back of our 6.0, but it has the rear deck extension. I had decided that I couldn't put one on our 8.1 because it doesn't have the deck extension. Perhaps I can make it work!

Did you consider attaching to the back wall for additional support?

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[GrampaKilt]

Steve, as you suspected, attachment to the trailer main frame is necessary in the absence of a bumper extension and particularly in this mod wherein the box doesn't rest directly on top of the bumper. Since the vinyl post elevates the box 5" off the bumper itself, I couldn't anchor directly to trailer floor cross member. I suppose I could have found wall studs for anchoring but just didn't want to screw into that perfect aluminum skin. What I did do is attach the strap shown in the picture to the rear bottom corner(s) and bolt it to the cross member so that the rear of the box can't lift up from overhang torque. 

[Capt J-rod]

I'm sure you know this and I don't want you to take it wrong, but be very careful putting weight behind the axle. I love the idea and have threatened to redo the bumper on my 21rbs for bikes or a generator. Very nice craftsmanship by the way.

[Steve Sanders]

I'm sure you know this and I don't want you to take it wrong, but be very careful putting weight behind the axle.

You are absolutely correct. That is a significant concern about this idea.

What I'm thinking is just enough room to store set up stuff that I'll need access to before I open up the camper and want to stow after closing it up.

The last time I had a trailer balance problem, I was pulling a Roll-a-Home camper behind my BMW K1100LT motorcycle. Tail-wag on that rig was an experience that I'll never forget and don't want to repeat... EVER!    BTW, I was able to control it and safely stop to rearrange the load.

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[GrampaKilt]

I hear you about tail wag, been there as well. Surprisingly. there's not a whole lot of space left over after placing a Honda 2000 generator (only fits lengthwise) and a 10L gas can in the chest. If these items are placed to the back, the weight is directly centered over the bumper which will go a long way to reducing potential wagging. I really don't need a box 20" deep, 16-12" would have been ideal if available and it would look better as well. Hmm, I could cut the chest down and reattach the front with some aluminum corner, rivets and caulking! (So many mods to do, so little time!) I'll be sure to update my towing experience to this site during our travels.

[Merlin]

Interesting solution to storage! There's always a need when camping to have a convenient place to toss the detritus of camp life.  However, as soon as you wrote "generator", I thought about weight. I'm not an engineer, so I can't comment about adding weight to a bumper originally designed to carry 0 lbs. However, I do have experience with weight distribution/balance in towing and if my math and guesses are correct, you're adding over 115 lbs to the rear with the genny and all the construction materials, sewer parts, and gas. Since you've commented already about it in response to others, I'm sure you've thought about how that will affect weight distribution/balance. You may need to increase the tongue weight to control sway. I added my Lund box to the tongue, just behind the propane tanks. I think the 16TBS needed some weight up front to prevent sway. I know others have added weight (sometimes a lot) to a rear bumper, but just be careful until you know the effects on the 14DB and your tow rig.

[GrampaKilt]

Thankyou for the replies and particularly for the respectful tone of them. Some have commented that 'I probably have thought about...'. Indeed, I have! For what its worth, read on or disregard...

Bumper storage is a relatively common mod on travel trailers. The strange thing in reading about a dozen+ installs is that not one mentioned any unease with towing stability. The reason, I suspect, is an idea I'll explain below. On the other hand, the main problem addressed was that attaching storage someplace along the bumper may cause its frame connection welds to fail due to constant torsion. Apparently this can happen even with 4" square steel bumpers (you can also blame rust) leading to at least one commercially available weld stabilizer https://www.youtube.com/watch?v=W7Ys33KTxHg . Obviously, the bumper needs to be reinforced especially one made out of aluminum tube. Some attach an extra cross member (I did). Others go crazy with more welding or bolt on plates at the frame connection. Directly attaching the storage solution to the back of the TT reduces torsion to nearly zero (me again). Or, span the bumper with a full width-of-the-trailer storage box and bolt it to the frame rails.

I should 'fess up. Like the other bumper storage mods I researched, I really have no concerns about towing stability either. The reason is found in playground physics. Basically, a trailer is a towable teeter-totter (aka seesaw, aka a simple lever) with the fulcrum located to the rear of the center of gravity so that 10% of the total weight bears down on the coupler. As a child, who doesn't remember balancing off the weight of a parent by having him/her move closer to the fulcrum?

These same lever dynamics apply to a trailer. If I wanted (theoretically speaking) to offset the addition of only a battery and 2 full tanks of propane to restore the original 10% tongue weight (TW), I'd need to load 184 lbs on the bumper (reinforced, of course) since it's closer to the trailer 'fulcrum'. That said, I find a higher TW tows better, although a properly tuned WDH and anti-sway bar makes the most difference. As for this mod, 110 lbs on the bumper is far under the maximum and even more so as TWs increase. For a more technical explanation, refer to IMG 1.

WARNING! WARNING! DO NOT LOOK AT THIS IMAGE IF—
* you found math and science stupid and boring in school
* you never went out to the playground because you were always helping in the library
* you are attracted to a certain common pet
* you lost your reading glasses