Need some advice/suggestions on new bumper

[wytaco26]

I want to try my hand at doing a 13" bob. I've seen a few bumpers here that it'll probably be styled after, but few if any pictures of what's behind them. My issue is that I realized with a 13" bob, I'd be cutting the frame down at or just passed the shackle mounts. This leaves very little room to work with in between the end of the frame and the preexisting crossmember.

I'd like to make this strong enough to where I'd feel comfortable enough to tow a light trailer or pop-up camper if I wanted to.

After talking with the guys over on TW, this is what I have so far.



Made out of this stuff-
http://www.speedymetals.com/ps-4772-...el-tubing.aspx

Any suggestions on the design? I plan on relocating the shocks not too long from now so would it be best if I removed the preexisting crossmember and fab up a new one for the shocks to be mounted to? I figured I could then move it farther forward, box the frame back from there and then have enough room for the bumper/recovery point/hitch receiver setup.

[Stoffregen Motorsports]

If you plan on doing some light towing, the bumper has to be strong in two planes. Vertical and Fore-Aft.

You should look at the bumper in two parts:
1st - tow point
2nd - bumper

If you look at how a receiver hitch is made, that should give you an idea of what areas are important to focus on. The crossmember has to be strong, I usually use 2" x .250 or bigger for this. You also need triangulation. The drawing you show has good triangulation in the fore-aft department, but what about vertical. I would put another crossmember at the end of the receiver hitch inside the frame rails.

I copied your drawing and added the crossmember in red.

[wytaco26]

Thanks, that's a big help!

What about relocating the preexisting crossmember? Okay to just plate the frame and make a new one farther forward?

[cape taco12]

Originally Posted by wytaco26

Thanks, that's a big help!

What about relocating the preexisting crossmember? Okay to just plate the frame and make a new one farther forward?

Boxing the frame while your at it might not be a bad idea. Although things can add up. Slap some through bumper clevis mounts as close to the frame rails as you can.

Edit: dont forget to let the wings stick out enough to add some tube on later. You know you will want to lol.

[WallyP226]

Fish plating the frame is an excellent idea. I was moving some rocks, put a couple dozen rocks on the tailgate. I started to notice bed-cab seperation. So I took the rocks off, started stacking Olympic weights on the tailgate till I could recreate the bed-cab seperation. It occurred on my 04 D-Cab at about 325-350lbs on the tailgate. I fish plated the frame all the to the rear cab mount.

FWIW, The class IV Toyota hitches were .250 square wall, with .250 frame brackets. Essentially tied the end of the frame togather. For a frame of reference, I have seen domestic 1/2 ton pick-ups with .188 wall hitches that are class IV rated.

Wally

[Stoffregen Motorsports]

Originally Posted by WallyP226

FWIW, The class IV Toyota hitches were .250 square wall, with .250 frame brackets. Essentially tied the end of the frame togather. For a frame of reference, I have seen domestic 1/2 ton pick-ups with .188 wall hitches that are class IV rated.

Wally

But what dimension tubing? When you go up in diameter, you can go down on wall thickness.

[NCFJ]

I agree with the addition of the cross member. I generally use 1.5" X 2.5" .188 wall for this. Tie the receiver tube directly to it and brace from there. It is also a good idea to extend the frame mounts through the bumper with holes drilled for shackles. I build them up to 3/4" and add a sleeve as well. Very strong, ties direct back to the frame.

[wytaco26]

Should I weld the bumper directly to the plated frame or should I make it removable?

[vegaskurt]

Originally Posted by wytaco26

Should I weld the bumper directly to the plated frame or should I make it removable?

Make it removable. Although welding it to the frame would be super strong and save you some fab time, there will come a day when you want to remove it. Or if your like me, build another bumper every 3 years.

[Stoffregen Motorsports]

Originally Posted by vegaskurt

Make it removable. Although welding it to the frame would be super strong and save you some fab time, there will come a day when you want to remove it. Or if your like me, build another bumper every 3 years.

I agree 100%. I try to make all of my bumpers and sliders removable, but sometimes the customer doesn't want to pay for it. The cost of sliders or a rear bumper can double if you want them removable.

[wytaco26]

Thanks for the help, I'll make it removable. Should be easier than I was initially expecting.

Got the bed pretty much done. I've been thinking about raising the gas tank while I'm boxing the frame. If I can relocate the charcoal canister (even just a little and build a bracket?) I could probably lift the tank about 2". Has anyone done this? There's no body lift.

[WallyP226]

Toyota factory receiver hitch was pretty large. IIRC 3"X.250 square wall, sticker on the side said it was rated for 5000K or 500lb tongue weight.

2011 Ford F-150 has a 2.25X.188 square wall, no sticker on the hitch, however Ford rates their factory tow package at 11,200 for a 5.4L with 3.73 gears.

Wally

Originally Posted by Stoffregen Motorsports

But what dimension tubing? When you go up in diameter, you can go down on wall thickness.