Jamboree Rack Design

[SR1355]

After seeing Cris B. inspirational rack design I decided to get off the couch and get to work.

Over the weekend I designed and built a full size mock up for a Jamboree Rack. Rack will be 18X48X4.75 mounted off spare tire mount. Spare tire mount will be relocated outward 1 1/2" and rack was designed to allow 35" tire on spare carrier.

Does anyone know a safe load limit for spare tire carrier. I use it as a step to roof rack right now and it seems pretty stout. My 200# seems to not bother it, I know that with the rack and tire, leverage is going to come into play but still think is should be able to carry a fair amount of weight. I hope to carry two 5 gallon J-Cans and a 58 QT cooler.

I've attached some images from modelling software as well as photochop of rack installed on H3. Plans and cut list are at fabricators for estimate right now.

Any input would be appreciated, I took tailgate apart and looks like connection of spare tire carrier is reinforced.
37244

37245

37246

[evldave]

A few things to think about, I posted some stuff like this on Chris's thread too. I've had my bike mounted to the rear tire mount for more than a year now, so have some experience with this. With 2 bikes and the 33" spare the rear gate will flex slightly at the mounting points even though they are re-inforced. A 58 qt cooler (75 cans) and 2 5 gal jerry cans is about 140# of static weight resting on the mounts. If you do nothing but drive on flat ground I have no doubt this won't be an issue, but I do believe that it will be an issue when off road, hitting bumps, etc.

I'm not trying to rain on anyone's parade here, but I actually took off the bike rack mount because of my concern over the flexing of the rear door. Your design looks real solid, and if I can see in the pics, you might even have two side braces that press up against the door? that would help take some of the load off the mounting bolts, but I still think a rear rack w/spare tire will cause problems when going off road.

If you can make the rear rack, why not make up a roof rack and put the spare up there? I did that, and it eliminates a ton of extra weight on the rear door and I'm sure you could load up that rack with all kinds of cool stuff and still have piece of mind!

my 2 cents...:D

[SR1355]

appreciate your insight and comments. quick question about your bike rack, did it mount after the spare, resulting in a lever action due to the bike being so far out from the gate. Thanks for the quick math on the weight of the cooler and cans, the rack material weights 56.32# give or take a # or two.

[bjc]

So that last pic is a Photoshop? Damn. Nice work.

[SR1355]

So that last pic is a Photoshop? Damn. Nice work.

Yeah, I modelled the rack, set-up camara in software close to actual phote angle then finished it in PS.

Couldn't figure out how to add dirt to the chopped rack.... now that would look good... maybe add the J-Cans and cooler for some fun later... :excited:

[evldave]

appreciate your insight and comments. quick question about your bike rack, did it mount after the spare, resulting in a lever action due to the bike being so far out from the gate. Thanks for the quick math on the weight of the cooler and cans, the rack material weights 56.32# give or take a # or two.

Yes, it mounted to the bolts holding the spare (there's pics somewhere on elcova w/the mount), and it did have lever action on the rear gate. After I moved the spare to the roof and just had the bikes on it, it still flexed but obviously not as much. I'd love to have someone stand on the rear bumper w/the bikes on (2 of them) and see how much the rear gate flexes when going over bumps.

As a note, I have beat up my hummer, and gone over good bumps w/the tire and 1 bike back there and there's no noticeable permanent deflection. When you do get this all done, and put in a cooler and jerry cans, see if you can measure a before/after deflection while fully loaded. I'm extra conservative, but if you prove the rear gate can handle the weight, super!

[SR1355]

60 plus views.... no additional comments....

:popcorn:

[Demo]

Well, I wrote a long comment but then decided not to post it. Didn't want to burst your bubble. :)

So here it is, I think that putting anymore weight on the already overwieght rear door is a bad idea. Unless you don't plan on keeping your H3 long, I predict that your rear door will begin sagging and will require readjustments becoming more and more frequent. I would put my time and effort somewhere else. Additionaly I think it will make access to your roof rack much more difficult. Not to mention the concern you have of pushing the tire out over and inch. Save your money and get a good adventure trailer. My two cents, hope it helps.:)

[Demo]

Oh yeah, your design looks great, I just don't think the vehicle is made to handle it.

[evldave]

I noticed in your pic you already have a roof rack. Why not just put the spare up there and mount the rack to where the spare mount goes? You could load it up real good and not risk hurting the rear door. Get rid of the whole cone-shaped thing and clean up the back and it would look real nice!

[SR1355]

While I agree it may be too much... I would think that the engineers at GM would know that a company coming up with something like this is going to happen and they would provide extra capacity in the design... maybe not. I guess the only way to find out is to do it and see what happens... could be an expensive experiment.

The saga begins... :shhh: :shhh: :shhh:

[HummBebe]

I think its going to look great!!!

I wouldn't over load it though. A couple of Jerry-Cans would look slick on it. But I've always been cautious about adding weight to any door.

I am impressed with the design.:)

[Demo]

I think evldave has a good idea. You could make a two tier rack for the back door and put the spare on the roof. The Iceland conversions I have seen remove the spare (hard to carry a 38+ spare) and make a cargo box for the back door. Either way you clearly have skills, and I can't wait to see what you come up, when I see it at Moab! :beerchug:

[SR1355]

I think its going to look great!!!

I wouldn't over load it though. A couple of Jerry-Cans would look slick on it. But I've always been cautious about adding weight to any door.

I am impressed with the design.:)

Thanks, hoping to have it or some other design complete for the Moab trip.

[SR1355]

I think evldave has a good idea. You could make a two tier rack for the back door and put the spare on the roof. The Iceland conversions I have seen remove the spare (hard to carry a 38+ spare) and make a cargo box for the back door. Either way you clearly have skills, and I can't wait to see what you come up, when I see it at Moab! :beerchug:

Maybe 4 J-cans below and trail rack above, it would be an easy mod to the rack currently designed.

[Hunner]

While I agree it may be too much... I would think that the engineers at GM would know that a company coming up with something like this is going to happen and they would provide extra capacity in the design... maybe not. I guess the only way to find out is to do it and see what happens... could be an expensive experiment.

The saga begins... :shhh: :shhh: :shhh:

Interesting observation since the design on Cris's thread starts with a rack pictured and offered by Amstar which is AM General which is how all this Hummer stuff got started. I wonder if they considered that it would really work or not?

[Demo]

prolly thought about it just as much as they thought about putting an I-5 with malfunctioning heads in the H3 .:giggling:

Or better yet, selling products through the stealerships only.

[Hunner]

Or the skid plates that are not wide enough to cover the shock mount hanging out there in space.
There site is now underconstruction.
The new owners of the local dealership actually showed me a book today from them but all I saw was high dollar H2 stuff. All the mods for H3's that were on the site are not in their book. They have been advertising for over a year and have not made most of that available in my area.

[excel25]

Why not use the same top and attach it in your trailer hitch receiver and let it rest on your spare tire, That would take stress of door and still be out of the way.

[garnerbiker]

We need to rip off the factory rear bumper and put an XJ style durango bumper. Then, you can have the everything you want atached to the rear bumper and still up high for wheeling. But NO, no one has made something like that yet unless it's all fabed up. It would be great to have the 2 cans, high lift, and spare on there off center and up a bit higher. Also, you can yank on that bumper as hard as you want.

http://www.durango4x4.com/rearbumpers.html

http://www.durango4x4.com/images/gallery/Elliot02.jpg

We need to make something similar to what they have and keep it low profile and close to the truck and not weigh 500#'s

[stagger_lee]

We need to rip off the factory rear bumper and put an XJ style durango bumper. Then, you can have the everything you want atached to the rear bumper and still up high for wheeling. But NO, no one has made something like that yet unless it's all fabed up. It would be great to have the 2 cans, high lift, and spare on there off center and up a bit higher. Also, you can yank on that bumper as hard as you want.

http://www.durango4x4.com/rearbumpers.html

http://www.durango4x4.com/images/gallery/Elliot02.jpg

We need to make something similar to what they have and keep it low profile and close to the truck and not weigh 500#'s

x2 :clapping: I agree. and swing out spare is kind of nice too. :beerchug:

[evldave]

I never did like swing out spares. Especially w/the swing gate of the H3, you gotta upen two things to get to the back - i'm always in the back of my truck and it's a pain opening both.

I think putting the spare up top and having a rack attached to the spare mounting bolts would be the trick. If you flipped this design upside down and had the rack line up w/the bottom of the rear door and attach to the spare bolts, that would be less stress on the door and it would look pretty cool too.

[CrisB]

Damn Paul, nice modeling software! You thought it out well. I loaded mine with a 40 Qt cooler packed to the rim with ice & sody pops, saw no difference on the rear door. Mine sits sturdy with that 3rd rear leg, it really doesn't do any levering on the framework, I'm good with it...but I wouldn't make it too big. Mine's 14x25x4".

Remember all, this isn't loaded up every day, just an added space to put some stuff. My trip to Moab ( and skiing in Breckenridge), will require a fully loaded roof rack, cargo bag, rear tire rack & interior....unless I want to pull a trailer over the Rockies. That rear rack will allow me to store like 8 extra square feet of stuff for the road, and will make my kids much happier.

[Jeff G]

Why not use the same top and attach it in your trailer hitch receiver and let it rest on your spare tire, That would take stress of door and still be out of the way.

I was kind of thinking the same thing. It would definately take the stress off of the rear door.:beerchug:

[SR1355]

Stopped by fab shop today for test fit, everything tack weld and had to do some minor mods. They should have fully welded up today, looks like I won't get it powder coated before the MOAB trip but at least I'll have it to do a shake down run with for any final design changes.

[evldave]

Stopped by fab shop today for test fit, everything tack weld and had to do some minor mods. They should have fully welded up today, looks like I won't get it powder coated before the MOAB trip but at least I'll have it to do a shake down run with for any final design changes.

Pics?? I took off the rear spare carrier yesterday, but didn't have time to weigh it. Gonna weigh it and the spare today to get an idea on how much the rear door was originally test with. Then, if you remove the spare and carrier, it will tell you (roughly) what you can carry without too much worry. I tell ya, though, that carrier is a lot heavier than I thought!

pics pics pics pics pics!!!!:jump:

[wpage]

Good Design!:grouphug:

[SR1355]

Picked up rack from fab shop, here's basket....

[SR1355]

Here's mount....

[SR1355]

Here's basket and rack....

[SR1355]

Here's before shot of back of H3...

[SR1355]

Rack mounted....

[SR1355]

basket mounted...

[SR1355]

clearance on wiper...

[SR1355]

spare carrier re-installed....

[SR1355]

spare re-installed...

[SR1355]

completed...

[SR1355]

completed 2...

[SR1355]

completed 3...

[fourfourto]

SR looks great.:beerchug:
You just clear it on your wiper,not that is does much good.


A question: Hows the aftermarket hitch working out,do you get hung up offroading?
I dont know if I should get that type or get a custom one put in my bumper.Thanks

[SR1355]

I spent about an hour at fab shop this morning tweakin' the design of the mounting tabs. I wanted them as flat as possible against the body for the most surface area to distribute the load. Tabs are 1 1/2"x2" and are flat on body so the load is over a large area.

Still need to get powder coated but out of time for MOAB trip. I can still access roof rack from rear bumper. I installed rack, spare, and stood on rack... minor bounce with my 200# moving up there... I plan on replacing stock carrier stubs with bolts, not comfortable with amount of thread contact on studs. It's over built, I'm sure I could trim quite a few pounds from rack with a redesign.

Fingers crossed that is stays put... time for a beer... :beerchug:

[SR1355]

SR looks great.:beerchug:
You just clear it on your wiper,not that is does much good.


A question: Hows the aftermarket hitch working out,do you get hung up offroading?
I dont know if I should get that type or get a custom one put in my bumper.Thanks

Thanks, I think I would prefer the factory hitch to this one I have, I plan on removing it for MOAB. It looks like a point of contact.

[SR1355]

One last thing, I have a cable lock that will keep thing where they are supposed to be...:D :D :D :D :D

[evldave]

Fingers crossed that is stays put... time for a beer... :beerchug:

LOOKS GREAT! NICE JOB!!!

[ictH3]

GREAT Job! That looks really good! :beerchug:

[SR1355]

Anyone know how you get those goofy studs out, I tried six point sockets but it's in between metric sizes...

Replacements at 10mm 1.5 pitch 30mm long grade 8 bolts.

[evldave]

Anyone know how you get those goofy studs out, I tried six point sockets but it's in between metric sizes...

Replacements at 10mm 1.5 pitch 40mm long grade 8 bolts.

1/4" wrench worked for me. They were a PIA to get out, but came out eventually.

[SR1355]

Thanks Dave, I'd feel much better if bolts and full thread contact...

[SR1355]

Rack survived cross country to MOAB :clapping: ....

Full color and two jerry cans half full... being alittle conservative at first. I full them up all the way for trip back. Tomorrow I strap full cooler on and hit trail.

See thread in Photos...

[SR1355]

Rack is now trail tested on Hell's and Seven Mile. Absolutely no flex in door sheet metal. Ran both trails with cooler full of ice, beer (not for trail), and food. I saw no need to take j-cans on trail, but if I was on longer trail (i.e. it would also be easier) I'd not hestiate to load her up.

[fourfourto]

SR how did you aftermarket trailer hitch hold up on the trails,Is being located under the bumper cause problems with it hanging up ?

I was thinking of having one custom installed in the bumper,It is much cheaper get a bolt on.I dont wheel as hard as you guys so I might get by with a aftermarket but I was worryed about getting hung up.

I noticed your rear plate got customized:giggling: :beerchug:

[SR1355]

SR how did you aftermarket trailer hitch hold up on the trails,Is being located under the bumper cause problems with it hanging up ?

I was thinking of having one custom installed in the bumper,It is much cheaper get a bolt on.I dont wheel as hard as you guys so I might get by with a aftermarket but I was worryed about getting hung up.

I noticed your rear plate got customized:giggling: :beerchug:

I dragged the receiver on a few obstacles but it took the punishment. I also was thinking of one custom built into bumper. I'm going to take a close look when I get home. Looking to get adventure trailer and I want receiver as high as possible.

[fourfourto]

Some local place is giving me a price,He wanted to look at a factory hitch first he's near the dealer.I got to call them back.
It looks like our bumpers would be cuts like the factory hitched bumpers..Behind bumper are square holes on the mounting brackets that are used for the factory hitch.


If he can do it cheap Ill go with the custom hitch,If he comes in high I will get aftermarket type.

[www.miami3drenders.com]

Great Job!
My observations, as architect:
1. your are creating in some way a path to direct all the weight going down (as static structures should be) but remember, all the weight is "failing" on the four bolts, and there is a lot of different forces compression, extension and torque, every time that you brake, press gas, gravity, overweight, different distribution of weight, etc. my humble opinion is that for your door life, you should put over the less weight as possible in this ingenious rack, and use rather of that the roof rack for heavy weights. Orr builds inside the door a multi-forces-receiver stainless steel bar mesh.
2. At the end is not bad at all over calculate the structure in this case because who cares about 3 pounds more in a hummer, but I?m really sure that right now you can stand up three 200 pounds guys on that rack (if you are using stainless steel as I can see, maybe is aluminum and I?m wrong.
So, now you know, in the next engineering project: less metal and better forces study
Anyway looks practical and ingenious.
Keep inventing solutions, not everybody put dreams in real life, you need ba.. to do it. I love to see guys like you bringing solutions to real life

[SR1355]

Thanks for the comments, I had a chance to use the rack at full load over the weekend with two jerry cans and full cooler. Wheeled on Drummond Island ORV trails and I can tell you that if it was goin' to fail it would of then. I have a little experience in load calculation, rotational forces, modulus, static load, etc. This proto type is over designed and I have revised plans that shave about 10# off the rack itself. I'm pleased with everything so far, we will have to see what time brings.

[SR1355]

Well after almost a year rack and rear gate are both doing fine. I certainly used the rack as expected this past year with close to 6 weeks on the road/trail. I've had several inquires about having some made for other members, not gonna happen but I will send link to plans and instruction for a nominal donation to cover R&D. These are high quality plans and instruction that any competent fab shop would be able to build from.

If you interested just send me a PM....

[TripWire]

After getting these plans, all I can say is WOW! Very detailed, very professional! Great work!! :beerchug:
Can't wait to get this put together and on my rig! Thanks Paul!