Rear Bumper Fabrication Question (1 Viewer)

[ScratchedFJ]

Hi All,

I've been trying to decide between building my own bumper, buying a kit, or buying a pre-made bumper. Last night I was poking around and realized that the factory rear bumper is the end of the chassis rail. Are there any downsides to welding/building a bumper that is directly welded to the frame? The two I can think of are 1) this would not be reversible and 2) if I smack my welded structure I'm smacking the frame so I would have a higher chance of frame damage. Whereas if I buy/make a bumper that bolts on and sits off of the frame these two risk are decreased. Did I miss any risks to fabricating and welding a bumper straight to the frame?


For reference, my rig is a beat up salvage title rig that I've been fixing up since Sept'20. I'm ok with this not being reversible (or reversible with a lot of effort).

 

[lumbee1]

If you are on a strict budget, a log bumper (2x4 heavy wall steel) will work. However, the 4x4 Labs kit is quite good and very popular. I have the 4x4 Labs kit with dual swingouts and love it.

 

[Broski]

Welded or bolted, if you hit the bumper hard enough it well bend the frame. I say welder up.

 

[Heckraiser]

You pretty much hit the nail on the head in terms of pros/cons. Just a personal choice at this point.

 

[Wermz]

I built my own bumpers. Just start cutting and dont look back.

 

[ScratchedFJ]

If you are on a strict budget, a log bumper (2x4 heavy wall steel) will work. However, the 4x4 Labs kit is quite good and very popular. I have the 4x4 Labs kit with dual swingouts and love it.

Not on a "strict" budget but definitely aiming for <$1500 with a stretch goal of <$750. <$750 definitely involve me welding. 4x4 Labs or Proline are my competing "purchase" choices.

Welded or bolted, if you hit the bumper hard enough it well bend the frame. I say welder up.

Fair enough

 

[ScratchedFJ]

I built my own bumpers. Just start cutting and dont look back.

Thanks for the encouragement! After I read your comment I went and looked at your build thread. It looks like you put a tow hitch receiver where the 4x threaded holes are/were in the factor bumper. Is that correct? If so what sort of bracing or support did you add to the receiver?

I really don't like how low the factory receiver sits (I removed mine) but would like to have one permanently affixed into my bumper build.

 

[Broski]

I made this one for under $100.00 , bolts to the frame. It's has taken a lot of hard hits with out bending the bumper or frame.

 

[Wermz]

I have about $300 in my rear bumper, that was for the latch, hinge, hitch receiver, bed liner coating, and the steel. I have even less in my front bumper, about $150.. make everything out of poster board first, it saves a lot of steel.

 

[categorytheory]

Haven't built a bumper yet for my 80 series, but from what it sounds like I did a similar build for my 4runner. The cross member is right behind the rear factory bumper so I stripped it down and then began building up from the rear cross member. If you are decent ENOUGH with a mig welder its a pretty easy task, minus all the fitting and refitting etc. I built the design however first in a CAD program to test the design but that was way over kill for how simple it ended up being. Below are a few pics of the process. Also I should mention this is MORE of a tire carrier than a formal "bumper". even though it HAS been hit by another car and they didn't fair too well

PM if you have any other questions too!

 

[ScratchedFJ]

Haven't built a bumper yet for my 80 series, but from what it sounds like I did a similar build for my 4runner. The cross member is right behind the rear factory bumper so I stripped it down and then began building up from the rear cross member. If you are decent ENOUGH with a mig welder its a pretty easy task, minus all the fitting and refitting etc. I built the design however first in a CAD program to test the design but that was way over kill for how simple it ended up being. Below are a few pics of the process. Also I should mention this is MORE of a tire carrier than a formal "bumper". even though it HAS been hit by another car and they didn't fair too well

PM if you have any other questions too!View attachment 2513498View attachment 2513504View attachment 2513507View attachment 2513508View attachment 2513498View attachment 2513504View attachment 2513507View attachment 2513508

That's basically exactly what I was imagining but with some plate metal sides and gussets for the rear quarter panels. I'm a mechanical engineer and live in CAD everyday so for me that isn't overkill.

 

[categorytheory]

That's basically exactly what I was imagining but with some plate metal sides and gussets for the rear quarter panels. I'm a mechanical engineer and live in CAD everyday so for me that isn't overkill.

Then you will be more than good! I actually put the design into a physics sim and tested the design under stress and vibration . I got waaaay nerdy about it. But yeah gusset it up, add in some extra cladding and it should be pretty straight forward and cheap. I don’t remember the final cost but it was pretty low. The swivel and end assembly I got from 4x4 labs I think and Ruff N Stuff or something like that A bit of trial and error though with fitting and tacking and removing etc though. That was the lion share of the time. Good luck and if you want I can send more pics to a PM.

 

[Delta VS]

Hi All,

I've been trying to decide between building my own bumper, buying a kit, or buying a pre-made bumper. Last night I was poking around and realized that the factory rear bumper is the end of the chassis rail. Are there any downsides to welding/building a bumper that is directly welded to the frame? The two I can think of are 1) this would not be reversible and 2) if I smack my welded structure I'm smacking the frame so I would have a higher chance of frame damage. Whereas if I buy/make a bumper that bolts on and sits off of the frame these two risk are decreased. Did I miss any risks to fabricating and welding a bumper straight to the frame?


For reference, my rig is a beat up salvage title rig that I've been fixing up since Sept'20. I'm ok with this not being reversible (or reversible with a lot of effort).

Remember seeing a few threads of folks who welded "side skirts" for lack of a better name to the frame for side protection. Pretty low profile look.

 

[LC4LIFE]

Your personal time/value equation will determine how much you will "save" going DIY. I did my own rear bumper and I can tell you it was very inexpensive in supplies, but extremely expensive in time. Not sure which is a better deal, built or bought.

 

[ScratchedFJ]

Remember seeing a few threads of folks who welded "side skirts" for lack of a better name to the frame for side protection. Pretty low profile look.

Yeah, I like the look of having it wrap around the sides and having some protection to the rear quarters. Also, since I'm planning on have a dual swing setup, I'll need supports at the corners anyways so wrapping the around from the corners makes sense.

Your personal time/value equation will determine how much you will "save" going DIY. I did my own rear bumper and I can tell you it was very inexpensive in supplies, but extremely expensive in time. Not sure which is a better deal, built or bought.

View attachment 2513564

View attachment 2513565

Your bumper is beautiful! I really enjoy the profile of it. I'm probably going to take some design ideas from you (hopefully you are cool with that). As for the time argument, that is a good point but to me this vehicle is my "fun" vehicle. I enjoy modifying it for the sake of working on it. It's one of my creative outlets effectively. Yes, I could be driving it instead of fabricating but honestly I enjoy both activities.

 

[JeepinPete]

I built mine this fall. I really didn't have the option to buy since I run a body lift. Drew it up in solidworks, printed out patterns, cut out the pieces using a metal cutting circular saw and a jig saw. I'd say I'm into it $250 in materials, but I do have a 5' x 5' piece of 3/16" steel left over.

 

[Dork]

I built my own. This was about $1000 by the end. I mocked it with cardboard and then drew those pieces up in 2d cad so I could get them laser cut. Most expensive parts were the spindles, I would likely use a big ass bolt and brass bushings if i did it again.

 

[Pascoscout]

Keep in mind that if you plan to just use the rear cross member and add to it that the frame material is pretty thin. This biggest thing I get on my bumper is hitting and dragging. If you caught an edge of the cross member on a rock I could see it bending that lower lip pretty easy unless you reinforce it.

Also if you add recovery points make sure you design them to attach to the side of the frame and don't just weld to the face of the cross member.

Here's mine. Designed and built my own but it's all bolted on. It takes a heck of a lot of abuse and never needs more than some new paint. I did weld in a tow hitch and supports to the rear cross member. The hitch isn't super stout but the tow capacity on these rigs is fairly low so I've never had an issue. With all the lights, latch, swing out etc I am probably into it $500.

 

[Broski]

Your personal time/value equation will determine how much you will "save" going DIY. I did my own rear bumper and I can tell you it was very inexpensive in supplies, but extremely expensive in time. Not sure which is a better deal, built or bought.

View attachment 2513564

View attachment 2513565

Your bumper has a clean simple look. Time wise DIY project can be expensive but there nothing like the gratification knowing you built it yourself.

 

[ScratchedFJ]

All,

Your inputs have been super helpful! I truly appreciate it. Last night I installed a new tie rod/tie rod ends and then began taking apart the OEM rear bumper. I took a bumper of measurements and began some CAD work. I'll post a screenshot of the bumper design tonight with the spindles and arm but I'm going to design and weld my own bumper and have it bolt to the factor 3x tow hitch mount points per side and the 2x threaded bungs on the vertical face of each side of the bumper. This will give a total of 10x bolted mounts and will have 6x bolts in tension and 4x in shear. Attached is my first pass of the bumper design.

My plan is to design the plates and send them out via one of the online services to get laser cut out of 1/4" steel plate. I will be using a 2" x 5" main tube. This sacrifices some aesthetics for simplicity and strength. Additionally, I plan on using the 4x thread holes in the center of the rear bumper as holes to begin my cuts to create a cutout for a tow hitch receiver. The tow hitch receiver will be welded in a double shear configuration through the main bar of the bumper. My only concern right now is in the horizontal plates that attach to where the factory tow hitch mount plates attach to the frame will be strong enough to support the bending moment of the weight of the rear bumper, spare tire (33" Yokohama Geolandar M/T w/ factory wheel), 2x jerry cans, and a hi-lift. I may go up to 1/2" plate for those two plates. I'm not sure if I want to run two recovery points or just use the tow hitch receiver for recover efforts (some input there would be great).