Suburban Rectangle Tube Bumper Thickness

[nutt7]

I am planning a rear bumper out of 6x2 tube with a swing down spare tire holder (35" tire). The bumper will support 100% of the swing down portion. I keep bouncing back and forth between 1/4" and 3/16" wall thickness. I want it stout, but not unnecessarily thick and heavy. I can save about 25-30 pounds with 3/16 (and maybe $30), but I worry about the spare tire part. I'd like the bumper to be able to be used to as a lift point too. Also, I plan on having a 2" receiver in the middle for very light duty stuff. I'd be too worried to tow anything heavy with a diy hitch. I haven't worked too much with metal fab, so any advice would be great. Thanks!

 

[Truckman4life]

My rear bumper is made of 6" 12lb I-beam steel and I cut and angled the ends and then cut 4" speed holes in it for weight savings. I also added a cut up factory hitch welded into it for lighter duty towing. It is about 1/4" thick and my mounting brackets are also 1/4" thick. The whole things weighs just about 100 lbs. I would say you should be fine at 3/16" and do your mounting brackets out of 1/4" and if there is a high stress area like where your tire carrier will mount then you can always add a fish plate in that spot to spread the load out so it doesn't tear but I think it will be just fine. https://ck5.com/forums/threads/the-spud-wagon-fixed-the-brakes.324516/page-7 and also the top of the next page.

 

[nutt7]

Thanks man! I'm kinda leaning to the 3/16. The mounting brackets will be 1x3 bar passing through the tube and used as recovery points. I also plan for the swing down mounts (1/4") to pass through the face of the tube so they get welded on both sides. Any other opinions?

 

[cyclic]

Here's a pic of my burb rear bumper and the basic sketch pic of the design.

It's a 2x6 tubing notched for the recovery points to pass through. Then angled and beveled to make it pretty. It's 0.120 tubing and I have a factory hitch just under it. The bumper plates I got from TNA. They are for a K5 and I had the "tab" extended 2 inches to pass through the tubing, You can see where I had to drill the burb frame to match the K5 bumper pattern, but it came out really nice. And with the extended front two extra bolts it's extreemly strong. Tying into the frame much further forward of the factory bolts. You can also just make out the heat line on the bottom of the bracket where I clearanced it for the hitch. I sent the hitch mod info to TNA, so he can probably include it already for mounting them on a burb. He might even have the hole locations so you might not have to drill those either.

 

[nutt7]

Here's a pic of my burb rear bumper and the basic sketch pic of the design.

It's a 2x6 tubing notched for the recovery points to pass through. Then angled and beveled to make it pretty. It's 0.120 tubing and I have a factory hitch just under it. The bumper plates I got from TNA. They are for a K5 and I had the "tab" extended 2 inches to pass through the tubing, You can see where I had to drill the burb frame to match the K5 bumper pattern, but it came out really nice. And with the extended front two extra bolts it's extreemly strong. Tying into the frame much further forward of the factory bolts. You can also just make out the heat line on the bottom of the bracket where I clearanced it for the hitch. I sent the hitch mod info to TNA, so he can probably include it already for mounting them on a burb. He might even have the hole locations so you might not have to drill those either.

I'll have to look into those plates for sure. Thanks, they look great, as does the bumper

 

[JoshHefnerX]

I'm working 4x8 sq tube 3/16 thick. It's a heavy chunk.

 

[nutt7]

I'm working 4x8 sq tube 3/16 thick. It's a heavy chunk.

I bet!

 

[LeoneSM]

I used to build bumpers for Jeeps sold in Quadratec and 4WD Hardware. I had step bumpers with spares and hi lift mounts. 3/16” is plenty. The weak point won't be the steel itself but the pivot point for the bearing on your spare mount. Beef up your mounting points and any recovery points. Any clevis mounts should go through the bumper and be welded on both sides. You can make something incredibly strong without being heavy.

 

[nutt7]

I bought the metal already, they didn't have 3/16 in stock so I went with 1/4. @LeoneSM I did plan to do my clevis mounts like you said. I am not going with a swing out, but a swing down. I'll be using bushed doms for support.

The nice part is, the guy gave me the 3/16 price...