Truck rack " whistle " Advice needed

[DSW]

Actually I have a friend with two at work that go all the way up to the bumper permanently.




The 1st I helped build when I worked with him, and is sort of what I am using as a jump off point. Mostly having to do with tie downs and the over the cab portion. We found that just wraping straps around the rail wouldnt work well for single items or rebar. The truck has loops on the uprights so that the straps can be longer and we wouldn't run into the buckels or the ratchet when tieing down stuff. The second truck is somewhat similar to the new truck, but the new one is taller. It was the truck we used to base the rack on the truck in the 1st pict on.

I was sort of looking for other options. But I appreciate the offer. Actually I just got done sending you an email or pm (I forget which) about the ceriated tungson question.

[tasslehawf]

Why is it SOO much higher than the roof of the cab?? What does that rect. tubing/mesh end-plate do in terms of wind noise?

Actually I have a friend with two at work that go all the way up to the bumper permanently.

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The 1st I helped build when I worked with him, and is sort of what I am using as a jump off point. Mostly having to do with tie downs and the over the cab portion. We found that just wraping straps around the rail wouldnt work well for single items or rebar. The truck has loops on the uprights so that the straps can be longer and we wouldn't run into the buckels or the ratchet when tieing down stuff. The second truck is somewhat similar to the new truck, but the new one is taller. It was the truck we used to base the rack on the truck in the 1st pict on.

I was sort of looking for other options. But I appreciate the offer. Actually I just got done sending you an email or pm (I forget which) about the ceriated tungson question.

[DSW]

Why is it SOO much higher than the roof of the cab?? What does that rect. tubing/mesh end-plate do in terms of wind noise?

The height of the rack over the crew cab was determined by the height of the back uprights. If I remember correctly they are 4' to the underside of the horizontal members. This was done so that stuff in the bed wasn't jammed against the lumber on the rack. You can't see it in that pict but we have 3' and 4' pins standing up in the back, a jumping jack and a fuel tank with pump. We also wanted to be able to get in the back without killing ourselves on the rear bar. Thought about making it removable, but it almost always has forms on the top.





We retro fitted the flat bed to the CC and deliberately kept the bed up to bypass some fuel fill problems that we have seen on flatbeds in the past with low bodies. That may also be part of why it seems so high.

As far as noise the old 7.3 non turbo diesel makes a racket as it is and all the metal pins don't help. I've also never seen the truck do more than 55-60 but never noticed any whistle. The greenish utility body I have pushed. That truck has run past 85. Trust me at that speed a whistle is the last thing on your mind! I don't remember it having one however.

Alot of thought went into the CC rack and I would be happy to answer the reasons why we did what we did on it.

[FusionKing]

FusionKing, yeah, I thought it should be just as stong also, but I've talked to a lot of old timers, and they all say that because the pipe is round, then it's stronger. More even weight distribution......

I'm sorry but I don't buy it

I would think if you start digging then you will find strength to weight ratio is better but not ultimate strength as in weight bearing strength over a span.

[DSW]

I'm sorry but I don't buy it

I would think if you start digging then you will find strength to weight ratio is better but not ultimate strength as in weight bearing strength over a span.

I agree with you on this. I know in a vertical aplilcation pound for pound round tube will beat other profiles. An alum soda can will support most peoples weight if loaded straight down. That a lot of psi on a thin thin wall. In horizontal loads an I beam is strongest for the weight. The taller the I web the more load is taken by the top and bottom cords and the more efficient. However the taller it is, the weaker it becomes when loaded latterally from the side. Hence why Wide flanges replaced I beams, and why the W profile is almost square in many applications.

I don't have any horizontal load tables for pipe, so I can not back this up. But why would the use a W beam instead of round pipe for most structural apps? Ok its got a flat surface, but I bet you could work around this if it was substantially better. I do know that an arch is one of the strongest ways to transfer loads to the ground as opposed to a flat beam. So the idea that a tube may self cancel some load may have merit.

[FusionKing]

Whether using square or round tubing both need to be designed around the advantages that the shape brings to the table.
You can simply take a 25 ft piece of pipe and square tube of varying thicknesses and shake them around and learn a lot.
25 ft pieces of sch 40 6063 t-4 aluminum pipe is very floppy in all directions.
Using steel square tubing and bending it with a bender could cause the square to become disadvantaged compared to round because of the collapsed sides from the bending process. Slight bends on the round can make it much stonger as well.
The perfect rack would implement a variety of shapes each serving its own purpose and used to its best advantage

[tasslehawf]

I would think that with sq. tubing, the folds would be stronger than the flat sides, therefore the flat sides are a weak point; whereas with round its all the same shape so no weaker areas.

[Bert]

I would think that with sq. tubing, the folds would be stronger than the flat sides, therefore the flat sides are a weak point; whereas with round its all the same shape so no weaker areas.

That's my thought!!!!!!!!!
FusionKing, I agree with you if you used different shapes to each one's advantage, but I think it would look like cr@p on one truck rack!!!!
Would be nice to have some side money, to get a round sched 40 pipe and square with the
same wall thickness, then put the same load on them and compare...