KK DIY Crossbars

Wearyman · **Joined:** Mon Aug 22, 2011 2:01 pm **Posts:** 161

Taking a few cues from the Fabrication section I'm currently working on fabbing-up some crossbars for my '08 KK. Now, since the KK has trapezoidal cross-section rails rather than simple tubes like the KJ, I didn't want to go the route of just using galvanized electrical conduit like so many of the other guys have done. Having round tubes laying on top of flat-top rails is a recipe for crimp and crush failures.

However, I am not a fabrication master. I haven't welded since high school metal shop and have no welding tools to speak of, so custom-building a clamp system is a non-starter for me. Thus I was forced to go with the more traditional U-bolts, at least for now. I may be looking into other clamping methods before I'm done.

So far, here is my current parts list:

2x 72"x1" steel square tubing

4x 1" U-bolts

1x black rubber 3" flexible plumbing joint

2x Rustoleum flat black "textured" paint

In case you are wondering, the plumbing joint is a short section of black rubber pipe. I will be cutting this up into small strips to use on the bottom of the U-bolts to help prevent them from crimping the rails.

So, I have a good selection of parts. Still looking for some square endcaps for the bars, but I'm sure I'll find some soon.

I am going to have to cut the bars down a bit. They are 72" right now, and that's WAY too big. I just don't know what the recommended size for them is. Any suggestions?

I'm also open to suggestions on clamping alternatives to the U-bolts. Putting a round bolt on a square tube just bothers me, but I don't know what else to do for this one.

This will be my first modification of any kind to my bone-stock '08 KK. I've been waiting for 3 years to do something with it (started as a lease, then bought it out) and I've been wanting crossbars for that rack for as long as I've had it, so they are my first mod. Wish me luck!

At The Helm · **Posted:** Sat Aug 27, 2011 6:24 pm

I used square u bolts and they fit perfectly. I also used some 1" flat steel to reinforce the factory bars. I have hauled lots of stuff using the 1 1/4" conduit and no problems.

At The Helm · **Posted:** Sat Aug 27, 2011 7:26 pm

Be sure to wipe down your metal with mineral spirits and prime before you paint. I would even sand them too.

Wearyman · **Joined:** Mon Aug 22, 2011 2:01 pm **Posts:** 161

Atthehelm wrote:

I used square u bolts and they fit perfectly. I also used some 1" flat steel to reinforce the factory bars. I have hauled lots of stuff using the 1 1/4" conduit and no problems.

Where did you get the square U-bolts? I've only been able to find the round ones.

At The Helm · **Posted:** Sun Aug 28, 2011 7:03 pm

My local hardware store. First place i looked, i guess i got lucky.

Wearyman · **Joined:** Mon Aug 22, 2011 2:01 pm **Posts:** 161

What size are they? 1 inch, 1.5, 2? Also, what size did you cut your crossbars to? I have 72 inches of metal and that's just too big. i need to cut them down but I'm not sure how much overlap I want.

At The Helm · **Posted:** Tue Aug 30, 2011 9:19 am

They are 2" wide, 3" tall. Front bar is about 53", i think about 52 for the rear. I wish i made them about 1.5" longer though to better secure full sheets of plywood.
Couple of ideas for you:
1.Have some 1x1" square plates welded on as end caps and ground smooth.
2. If you cant find the proper u bolts, make your own. You could use threaded rod bent into your custom bolts, then grind off the unused thread. Better yet, plain steel rod and use a pipe threader to make your own threads if you have the means to do so.
3. Drill the top holes in your bars just big enough to fit a socket in and tighten nylock nuts and washers to the bottom inside of the bars. This way you can't see the nuts and it will look more professional.

Wearyman · **Joined:** Mon Aug 22, 2011 2:01 pm **Posts:** 161

Atthehelm wrote:

They are 2" wide, 3" tall. Front bar is about 53", i think about 52 for the rear. I wish i made them about 1.5" longer though to better secure full sheets of plywood.
Couple of ideas for you:
1.Have some 1x1" square plates welded on as end caps and ground smooth.
2. If you cant find the proper u bolts, make your own. You could use threaded rod bent into your custom bolts, then grind off the unused thread. Better yet, plain steel rod and use a pipe threader to make your own threads if you have the means to do so.
3. Drill the top holes in your bars just big enough to fit a socket in and tighten nylock nuts and washers to the bottom inside of the bars. This way you can't see the nuts and it will look more professional.

Interesting ideas. I think I'll pass on the end-welding though. I don't have access to welding equipment or a welder, and paying someone to do it defeats the purpose of DIY. I found a place online that I can get end-caps cheap. (www.stockcap.com)

I like the idea of making U-Bolts. Good to know I'll need 2" ones.

Not sure that drilling through the top of the bar would be good though. That would only leave one side of the "box" supporting all that weight. I think I would rather just flip the setup around and put the bolts on the bottom. I can always use a crescent wrench to loosen and tighten them.

bhudha1 · **Posted:** Wed Aug 31, 2011 5:42 pm

If you live near a electrical supplier like Graybar or CED you can pick up some unistrut or kendoff clamps. They make square ones. I work for Graybar thats my plan. You can get them in stainlees or galv. Make sure that you clean anything you buy because all of it will some type of oil on it to protect it. Or look up Action Bolt and Tool online. I dont where you are but every large city will have a Graybar or just outs ide of town. Let us know how it turns out.

Wearyman · **Joined:** Mon Aug 22, 2011 2:01 pm **Posts:** 161

One more question; What's the spacing of your clamps? You have to drill holes in the crossbars, so what did you measure between the center holes? IE: The space between the two inside holes on each end of the bar?

==0=0=============0=0== <--The crossbar. holes represented by '0'
--------^This space^--------

At The Helm · **Posted:** Thu Sep 15, 2011 11:43 am

Wearyman wrote:

One more question; What's the spacing of your clamps? You have to drill holes in the crossbars, so what did you measure between the center holes? IE: The space between the two inside holes on each end of the bar?

==0=0=============0=0== <--The crossbar. holes represented by '0'
--------^This space^--------

Yeah thats the hardest part. I could go out and measure mine for you, but if i'm off even a little bit, its gonna screw up your rails. What i did was get the bars cut to the length i wanted, then lay them on your roof just the way you want them. Now open a rear door, stand on the door sill, put your u bolt upside down and look directly over it to see where it will line up. Now take a sharpie and make your marks. Do this to all four corners and take it to a drill press and drill out your holes. You dont have to use a drill press, but the bit needs to be perfectly vertical when cutting the holes, otherwise you'll have a hard time getting the u bolts through.

Sagerist · **Posted:** Sun Nov 20, 2011 10:02 pm

Just copied this mod with 3/4" steel pipe, the truck bed rustoleum, and round u-bolts instead of square

but it works. so far, very happy with the results and ending up using corks from wine bottles as end caps for the time being until i can find something else more permanent. :ROTFL:

May try using the rustoleum spray and see if it coats the cork enough.

Wearyman · **Joined:** Mon Aug 22, 2011 2:01 pm **Posts:** 161

Thought I should update this post as I actually finished my crossbars a while back. I ended up using square section steel pipe and square Ubolts. I sanded the bars and then painted them and the mounting hardware with black textured rustoleum paint. I filled the ends with silicon sealant and the pushed squares cut from a black rubber pipe fitting into them.

Unfortunately, the silicon was white because that's all i had available, so that kind of messes up the look a bit, but the bars are strong and tough, I've already carried several heavy items on it and it's held up fantastically.

I was also able to adapt the bolt holes in the bars so I could put the bolts open-side down, thus making it easier to carry wider items without risk of punching bolt shaped holes into them.

Here are some pictures:

I may still buy some proper end caps for them, but for now the silicon + rubber squares do the trick.

One disadvantage of the square bars: They "moan" at highway speeds. I've noticed a low frequency wind noise that shows up at higher speeds ever since I put them on. I suspect they aren't helping gas mileage either. I may have to add a wind deflector of some kind. I suppose I could DIY up something like that too. I'll have to see what I can do with it.

Sagerist · **Posted:** Wed Dec 21, 2011 10:50 pm

Good work, it looks good. I had the same moan or something similar with my bars. However, when i put my ski racks up there the moan went away and it sounds fine. I was even thinking about a wind deflector but won't need it until i take the racks off, and by then i will probably put a basket up there.

musclezmarinara · **Posted:** Wed Dec 28, 2011 1:07 pm

or you can buy the THULE LOAD BARS

Wearyman · **Joined:** Mon Aug 22, 2011 2:01 pm **Posts:** 161

musclezmarinara wrote:

or you can buy the THULE LOAD BARS

Yes. Yes I could. For about 2-3 times what DIY-ing my own bars cost, and without the personal satisfaction of making my own bars.
I'd also end up with weaker aluminum bars able to carry LESS weight, and in a color (grey) I dislike.

But yes. I could have bought some bars.

:lol:

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