Bumper strength

[8177]

Is the stock CJ7 rear bumper strong enough to hold one of the aftermarket spare tire rack/combo equipment carrier. Or does it need to be replaced. I have seen a couple of racks that look like either there is a piece of the rack that mounts over the bumper or replaces the bumper. I want to try to fabricate something and I wanted to attach it to the bumper. Or what ever the piece the bumperetes attach to.
Jim

 

[69jeepcj]

Yes, that should be fine. That is actually the rear cross member and a bumper can attach to it, but most people don't bother. I think the jeep I have now is one of very few I have had that actually has a real bumper on it. Just let the weight of the tire be on the bumper, and not the side corners of the jeep. You can latch the carrier shut at the corners but I wouldn't have them support weight. good luck

 

[AZJEEP]

Yes, that should be fine. That is actually the rear cross member and a bumper can attach to it, but most people don't bother. I think the jeep I have now is one of very few I have had that actually has a real bumper on it. Just let the weight of the tire be on the bumper, and not the side corners of the jeep. You can latch the carrier shut at the corners but I wouldn't have them support weight. good luck

Fabricate two rectangular plates ( washers ) at a1/4 inch thick. Make them to fit inside of the rear crossmember c-channel. Drill them in a two bolt pattern to match the rear bumper. Make them 3inches long by whatever dimension will let the plates install flat against the inside of the rear crossmember c-channel. Install the bolts through the bumper, then crossmember, then new plates. This will make the connection solid enough for rough trail use by stopping the flex in the crossmember.

 

[8177]

Thanks for the tip. I know the tank will have to be dropped to get access to the back of it, unless i develop some super strong skinny fingers, can the cross member be removed. I have dropped the tank twice already when i installed a new sending unit and when i installed the fuel injection kit. I looked at the crossmember to see what i needed to install a rack on it but didn't notice if it was welded or bolted on. I know i can just look at it but I'm not at home.
Jim

 

[J Smith]

Just some thoughts about your project if I may.

When mounting a swing-out tire carrier to any Jeep, you want to have an exceptionally stout bearing and bearing mounting surface. The weight of your tire and wheel alone dictate this, but add the bouncing and gyrating that will occur to that and any feeble attempt to hold all that weight for any amount of time will expose any weaknesses. One of your first considerations should be to use only Grade 8 hardware... (nuts and bolts) to mount any of your attachments. Anything less may not stand the load. You don't want the entire bumper pealing off when the bolts come loose and then break or just break because the strain was too great.
Second, the bearing should be welded both bottom and about 3 to 4" above the bottom to give it enough bearing surface to stand the strains. Above the second weld is where the actual swing arm should extend from. If you look at any quality rear bumper with a swing-away carrier, it will be similar to what I am trying to explain. Learn from those who have learned the hard way in many instances. The "gate hinge" must be over built to stand-up.
Good luck on your project.

 

[8177]

Thanks. I've been going over the overall design and bumper attachment. I have not thought much about the bearing yet. Have not gotten That far into it really but I don't think I would have thought much about it. I was thinking the bearing would just have to be strong when swinging it out and the bumper would take all the abuse. On to plan 2. LOL thanks for the input. And by all means let me have any more thoughts.

Well I guess I should be saying I've been mulling over strengthening the cross member or rebuilding it. Not much further than that Right now. I think about things long before I commit anything to paper. But Good warning.

 

[8177]

I really don't want to go through the trouble to remove the rear cross member. Seems like is not a simple operation. If I take some 3/16 or 1/4 ( probably 1/4) u channel and install it over the Cross member do you think this would beef the area up enough to hold a swing out tire carrier. I would use the existing frame brackets, located on the inside of the frame, and add a bracket to the outside of the frame and duplicate what the inside brackets look like. Use some of the existing holes in the cross member to bolt up in the center of the channel. Bolt up the ends in an existing hole by the body mounts. I personally think this would work. I would use this as the base of the carrier. Any input?

 

[69jeepcj]

Just my 2 cents. I think the x-member will be fine. AMC mounted the carrier on the corners of the body and it lasted for years before giving up. I think a frame x-member is MUCH stronger than the body panels. Others may have actual experience in this area though, and if that's the case I would take their advise. You could make L brackets and bolt them to the side of the outside of the frame then to a actual bumper with a swing out carrier for added strength.

 

[8177]

Your 2 cents buys a lot on my posts. I think this is how I'll go. fab a bumper of some sort and mount it as I described. weld some brackets inside the bumper structure to mate up with existing hard points and bolt holes on the cross member.

 

[AZJEEP]

Your 2 cents buys a lot on my posts. I think this is how I'll go. fab a bumper of some sort and mount it as I described. weld some brackets inside the bumper structure to mate up with existing hard points and bolt holes on the cross member.

THIS is the tire cage I fabbed for my yj. I attached to my old smittybuilt tube bumper. no connections to the body at all. there was flex in the c-member till I put in the backing plate washers. she's golden now!

 

[AZJEEP]

ok, finally got the pics sized. i still have other things like a mt.bike rack, and roto-pax brackets i want to fab on it. i don't know yet if i want the hi-lift jack to go back there, or up on the front bumper somewhere?

 

[69jeepcj]

The more I thought about it yesterday, I thought "why did you write that", must have been too early. I have heard of people breaking their cross member off trying to pull someone out that was stuck. I looked at how mine was attached, and it isn't attached to the cross member at all. It has two plates on the back of it that the frame rails fit right in between and the plates are bolted through the frame rails and not the cross member at all. Sounds kinda like you are doing yours but through the frame instead of the x- member.

 

[8177]

I was going through to the frame rail brackets, add two more brackets on the inside where there are none. It wont really be attached to the frame rail now.
AZJEEP I can not see your pics

 

[AZJEEP]

I was going through to the frame rail brackets, add two more brackets on the inside where there are none. It wont really be attached to the frame rail now.
AZJEEP I can not see your pics

My pics are UP NOW!

 

[SteelHeadz]

Very nice!! Great job!!