How much weight can my bumper support?
I am looking into mounting a toolbox to put batteries in on by back bumper. The bumper itself looks to be pretty solid and the weight will be distributed over 4' of the bumper. Anyone have anything he...
Forum Discussion
tkoden wrote:I have done what you are proposing. I had 1160# TW, and the TT hitch socket was rated for a max of 1200#. Too close for my comfort zone.
The whole goal of the project is to remove tongue weight. Right now my 7k trailer has about 1100 lbs of tongue weight. If I can remove 300 lbs of weight and get closer to 12% tongue weight I would be much happier and so would my TV. My calculations are this:
Currently on Tongue
2 GC2 Batteries - 130lbs (62 each)
1 Group 24 Deep Cycle - 50 lbs
Total Weight - 180 Lbs
Planned on Bumper
4 GC2 Batteries - 250 Lbs
Battery Box (with cables, disconnect, etc) - 40 lbs
Total weight: 290 lbs
It is roughly 2.5 times as far from the hitch to the tires as it is from the bumper to the tires so if you cut that number in half you get about 115 lbs of tongue weight removed plus the 180 lbs of batteries you get 300 lbs off the tongue.
So I cut off my rear bumper and welded 1' frame extensions on, then rewelded the bumper to them.
I used some angle iron and expanded metal to make mounts for my two 6 volt batteries, and a large basket (for outside storage items like carpet, leveling blocks etc.) between the new extended frame rails. I had a 8" tall I beam frame, and got exact matching pieces at a metal supply yard for the extensions.
There are some considerations for this project.
First I wouldn't be too concerned about a high TW in itself. Only if it can become a problem. Such as being too high for any of the rated components.
TV, receiver hitch, or TT hitch socket.
Next, just how stout is the TT frame? There are some pretty lightweight ones out there, and I would make sure that it is strong enough for this modification.
Keep in mind that the loaded TW is not a static number. It will change in the course of a trip. As items are consumed/used and redistributed in different locations in the TT. Freshwater gets used and ends up in the black and grey tanks. Food/beverage from the fridge and cabinents gets consumed and ends up in the black tank(s), propane gets consumed and it's weight removed from the TT, and some other items may get used and then loaded in different locations for the trip home.
This can have the effect of increasing OR decreasing the TW. There are a LOT of variables in this calculation. Everyones TT is laid out differently, and everyones usage is different as well.
So after considering all of this, and you still want to do it.. Don't use the bumper to support any weight. It is made of really thin metal and will fatigue easily and tear like tissue paper.
About the only safe thing to store in it is a sewer hose. Other than that, it is for decoration only.
