Defender Rack

[TruLiberty]

I'd love to pick one up but anyone who has, can u enlighten me to what the diff between a welded one and a screw together one is/ benefits of each?

I would assume the welded one is stronger but do both weigh/perform the same?

Where did you get yours from/what size?

Thanks for the info guys! I'll be putting Hella500's on this bad boy. :-D

 

[Ry' N Jen]

Well I checked out their products... I'm sure they are just as good as any other roof top luggage/ equipment basket on the the market!
Then I looked at the "Jeep" section...
"Excutive Access"
Riiight!
Only one Jeep vehicle shown!
Come on, really?

If that is your taste and it fits the personal requirements of what a roof top gear basket is supposed to provide you, then go for it!
Then there are those "Defender Light Cage" systems they sell...
"Off Road Poser" Equipment as far as I am concerned!
Looks good from a far... But far from good!

 

[tjkj2002]

I had the welded 4'x4'x4" Defender rack on my KJ for about 2 years,attaches directly to the rails via four u-clamps.I liked it but opted later for a much stronger setup that ended up only costing about $200 more then the Defender rack and came with all metal side rails.

Defender rack mounted on my KJ............

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The better Rock Lizard Basket Rack..............

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[Ry' N Jen]

I had the welded 4'x4'x4" Defender rack on my KJ for about 2 years,attaches directly to the rails via four u-clamps.I liked it but opted later for a much stronger setup that ended up only costing about $200 more then the Defender rack and came with all metal side rails.

Defender rack mounted on my KJ............

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The better Rock Lizard Basket Rack..............

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Exactly!

Why buy SH T when you can buy quality the first time!

 

[TruLiberty]

well the rock lizard doesn't have the high front and rear rails that i could attach thule accessories to and is crazy expensive lol. Defender looks easier to mount HLJ and shovel to as well.

check out this shoddy rack, but props to 4wheelaholic on making it. http://www.lostkjs.com/forum/phpBB2/viewtopic.php?t=44209

lol Durangotangs roof rack is Awful looking lol!

 

[TruLiberty]

oh and i want tjkj's rig but with silver on the top...ur rig is my build guide man just letting you know

 

[offrovering]

im a fan of the "integrated" look myself, when a rack looks like it belongs, if you know what I mean. TJKJ is more in line with that, this isnt... in my opinion.

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[Boiler]

I'm making aluminum racks that bolt to the roof and have options for crossbars, removable/adjustable or welded. You can check them out at the link below. I haven't posted in this website about them yet because I was waiting until my website was done. We are in full production now and have a couple base racks built and waiting for a home.

http://www.lostkjs.com/forum/phpBB2/viewtopic.php?t=40168&start=160

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[kj924]

I'm making aluminum racks that bolt to the roof and have options for crossbars, removable/adjustable or welded. You can check them out at the link below. I haven't posted in this website about them yet because I was waiting until my website was done. We are in full production now and have a couple base racks built and waiting for a home.

http://www.lostkjs.com/forum/phpBB2/viewtopic.php?t=40168&start=160

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That's a sweet looking rack Boiler...keep us posted on the web site as I will be looking at pricing one of these from you.

 

[Boiler]

We're in production now. We're on our fifth rack now. I'm just letting the website come after I've got more than just one item for sale. I'm putting together some designs for rock rails and a gas tank skid at the moment, and once we've got those designs down I'm going to make the website.

We'll have a couple in stock after this week, will just need to add options. The link in my sig should lead to a thread that shows all my pricing and pictures. Page 9 is accurate. It is kind of a messy way to promote your work, but I'll get there.

 

[kb0nly]

Not to further hijack the thread... But i got to ask Boiler on that custom rack, this just bolts on in place of the factory roof rails? The mounting holes for the lights are drilled through that front bar or are they on mounting tabs? Hard to tell in the picture.

EDIT: I followed some of your links and saw the pictures of the rack. Answered my own question on the mounting and light tabs..

Now i have another question looking at your pics on the other forum. You ran the light wiring down through the tube to the roof and you mention drilling a hole in the roof under the foot of the roof rack, how do you seal that up then??

 

[Boiler]

basically the wire's run through the tube, out a hole in the foot. I drilled a hole in line with that which was just larger than the heat shrinked bundle of tubes. With the rack propped up about 1" from its final position, I used RTV sealant and generously sealed the bundle to the roof. Once dry, we crammed that extra inch of wire up into the rack tube and bolted it down.

There is also a 1/16" thick rubber insulator under the foot, which would act somewhat light a gasket, but the RTV handles the bulk of the sealing. No leakage yet after a couple good downpours.

I'm not the first to do this either. It doesn't have to be done this way either, its just so clean.

 

[kb0nly]

Ahh ok, thanks for that info!!

I'm at a crossroads, i'm either going to save up for a roof basket or just put a crossbar and some lights on it now and maybe upgrade later. I was just looking at how to run the wiring and then i saw your pictures and thought that might be a good way to do it even with the stock roof rack bars, it's hidden and not inside the door weatherstripping or anything like that. I like clean wiring and not afraid of drilling holes, i was just curious if you were using some grommet or such but now i know!

Good old RTV and a drill will be in my future.

 

[Boiler]

Yeah the guy working on it with me was all for a grommet, but my wire bundle was almost 5/8". It fit tight in the hole and the RTV was my grommet. He wanted me to silicone the grommet and I just looked at it as two places to seal instead of one. Grommet to wires, and roof to grommet.

 

[TruLiberty]

Hey Boiler, can ur rack be customized a bit? get the cross bars closer to the roof and the placement of the welded cross pieces @ max distance instead? ill photoshop an image in a minute to show what i mean.

 

[TruLiberty]

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should be able to tell what im talkin about here.

 

[Boiler]

Yeah I see where you're going. It is not ideal though. Basically the entire bottom of the rack is in a flat plane who's closest point to the roof is at the center (lengthwise and side to side). The roof is basically shaped like a beach ball. Currently you could only get a skinny finger between the roof and the rack at that point. That is why the front and rear appear to be sitting high. If you lowered them, the middle would touch.

As far as the welded crossbars are concerned, I originally had them even with the siderails, but that meant that had to be located behind the bends, in the straight section of the side tubes. By welding them mid bend, they got lowered 1/2", but gained 3" each on usable space. I could move them out more, but as you get into the steeper part of the bend it begins to move down faster than it moves out. You end up with crossbars that only create like a 1.5" lip to gain another 1.5" usable space. Currently the top of the crossbars sit 2-1/2" above the surface of the bottom of the rack. You could make the siderails taller and have the front bend be 90 degrees, but much taller and you're talking about a really weird looking rack.

The removable crossbars end up even with the siderails height wise, and they sit a little farther out as well.

 

[TruLiberty]

another question boiler, how strong is the rack? for instance would it support a person standing on it? im not sure how strong aluminum rails are.

 

[Boiler]

Short answer: If you can get yourself up there, the rack will support you just fine.

Long answer: Aluminum 6061-T6 has a similar yeild strength to the steel used in most tubing. This means that it will take a permanent set at roughly the same load. It will however deflect (and spring back to original shape) more than steel will under a given load. I ran FEA (Finite Element Analysis) on my model when sizing my tubing. FEA is a tool used by engineers to calculate deflections & stresses in a target part or assembly. You create a mesh of lines and nodes, apply loads and supports, and the program calculates your deflections and stresses at each node. I used the ANSYS 10.0 FEA program and Autodesk Inventor solid modeler to do my analysis. Yeah, it may be a little overkill, but you can expect anything I build to have this level of attention put into it's design.

Basically I set it up so that a 300# load on any one point of the rack bottom would not 1) breach a safety factor of 3 for strength, or 2) deflect more than 1/4" (half the gap between the rack and the roof). I put the load on the center of one of the center tubes, and it easily passed both of those tests. Imagine a 300 lb. guy standing on one foot at the weakest position, and having no issues.

Next for a dynamic test I considered a 600# load spread over the center two tubes and recalculated deflection and stress with the same requirements. I thought this 600# test would reflect 200 pounds strapped in probably the worst case for the rack, and being put through 3G accellerations on the road (ie: rough bumps). It passed as well, as the images below show.

WARNING: The rack can handle a lot of weight, especially when standing still (loading, unloading). However, I'd recommend 150 lbs or less offroad, considering the owners manual rating for the Jeep Liberty roof. Also, driving with a lot of weight on the roof would require serious strapping and could hasten rollovers, handling oddities, and would catch more wind. I will not be held responsible for damage caused to your jeep or people due to overloading the roof.

FEA Mesh

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FEA Forces and Supports

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Deflection under 600# destributed over 2 center bars

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Von Mises stress under 600# destributed over 2 center bars. Von Mises stress is a method of calculating stress when concerned about yield strength.

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[Boiler]

If you weigh more than 300 lbs, you're still ok. In fact a 450 pound man would still have a safety factor of three and not deflect to the point where it touched the roof.

....if you're over 450 lb., use very subtle movements when walking on my rack...