Cage Design Opinions

[Deuling]

In all seriousness.

i think ill do DOM b pillar hoop, and hrew the rest.

Hopefully that allows me to get a few more sticks for bumpers and other things.

 

[sponsoredbydad]

Adam I chose all dom because going fast usually means more than 1 or 2 rolls if and when things go wrong, that and our dunes(West Coast) allow for multiple rolls because they are very tall and steep and all it takes is one split second of power loss and hold the f-on. I have seen side X sides roll up to 10 times on some of these hills and quads even more. One more thing I never thought about until I saw it happen. A sand car rolled and slid on it's roof, all the sand went thru the cage and they lost at least 6-12 inches of head room while sliding., So with that I'm gona build me an aluminum roof like a sand car or buggy would have to slide on. You got a cab roof i forgot.

 

[Deuling]

Adam I chose all dom because going fast usually means more than 1 or 2 rolls if and when things go wrong, that and our dunes(West Coast) allow for multiple rolls because they are very tall and steep and all it takes is one split second of power loss and hold the f-on. I have seen side X sides roll up to 10 times on some of these hills and quads even more. One more thing I never thought about until I saw it happen. A sand car rolled and slid on it's roof, all the sand went thru the cage and they lost at least 6-12 inches of head room while sliding., So with that I'm gona build me an aluminum roof like a sand car or buggy would have to slide on. You got a cab roof i forgot.

Good info dude. Our dunes is tiny.


Hey i sent you a pm on the fb this morning.

 

[ktmoutfront]

I will chime in.

How many medium speed crashes have you seen in a 5000 pound truck. I'm talking about 50 mph or so. Back over front and smack down on the roof. Sand is not soft when being smacked down on it. Watched too many bad ones in Glamis. Watched a Bronco roll 13 times down Comptpetition Hill. Completely destroyed the cage. And remember, you said you wanted to do Glamis some day.

A, B and C pillars are to be DOM 1.75" x 0.120" minimum. If you run hrew for cross ties, you should have more cross ties. Gussets in corners are a bonus. But the tube will rip at the gusset. 0.120" wall on all of it.

I knew my truck was going to land close to 7000 pounds, so I did the 2"x0.120" DOM for the pillars. I screwed up when I bought the tubing for the shock mounts and ended up with way too much 1.5"x0.120" DOM, so I used it on the rest of the cage. Wish I used 1.75"x0.120" DOM. That said, I feel real good in mine at 70 mph.

 

[70jimmy]

I feel very comfortable in my cage. I used 2" .120 wall DOM throughout. I still want to put in a few more bars like in the windshield area. But I am very confident that it would handle a high speed multiple roll event. Hopefully I never have to test it.

I didn't want to feel like gee I hope it's strong enough. To me the cage is not where I want to cut corners.

 

[blazinzuk]

Sand is not soft. It displaces quickly but try to compress it and you see sand is actually really hard

 

[ion]

This thread needs more pictures. ...

 

[Stomis]

Gussets in corners are a bonus. But the tube will rip at the gusset.

Using 1 in to gusset/45 hard corners should aid greatly in that.

Sand is not soft. It displaces quickly but try to compress it and you see sand is actually really hard

Adam makes one sarcastic comment about sand being soft...

 

[Kay86K5]

There is a lot of great info in this thread, but what you have to realize is that everyone has built their cage for their specific area/wheeling trends. I would totally agree that if you are doing anything high speed, than at least build the main pillars out of DOM, if not the whole thing, but if you are not doing high speed, than HREW with the proper gussets and triangulation will hold up just fine.

Like you Adam, I looked at all the prices before starting my cage build a couple months ago and was amazed at how much cheaper I could get HREW. Then I did some thinking as to what my rig will actually see. My rig is not street legal anymore (trailer it everywhere), and is built for slow crawling which is what I prefer to do. Couple that with being an internal cage, I felt fine going with HREW for everything. And now that mine is pretty much done, I can say that I feel very confident that mine will hold up good in a 1 or 2 rollover. But I imagine mine will just get flopped on it's side a couple times.

Don't know if my comments will do anyone any good , but I read all the debates on DOM vs. HREW and so on...and I really think you need to decided exactly what you want to do with your truck and build a cage that can handle that type of wheeling. That's the end of my $0.02

 

[muddermilitia]

This doesn't apply to Adam's cage as much, but for anyone wanting to run HREW for their cages/sliders/bumpers. Straight sections could always be sleeved for added strength. That's what someone did on the rock buggy chassis I bought a few years ago. Entire chassis made from HREW but then the straight sections in the middle were sleeved since they are the ones that would most likely hit a tree or rock

 

[Deuling]

One thing I wondered is, are there good statistic comparisons between the two, actually showing how one is that much stronger than the other?

From what ive seen its more the grade of steel, than the manufacturing process.

Also a lot of variables in just saying "yah I saw a hrew cage bend really easy" or "yah my dom cage has lasted 10 rollovers". Need to look at designs, crash circumstances, the builder, welds etc.

Is the material itself really that big a factor or, is that more opinion based?

 

[Stomis]

One thing I wondered is, are there good statistic comparisons between the two, actually showing how one is that much stronger than the other?

From what ive seen its more the grade of steel, than the manufacturing process.

Also a lot of variables in just saying "yah I saw a hrew cage bend really easy" or "yah my dom cage has lasted 10 rollovers". Need to look at designs, crash circumstances, the builder, welds etc.

Is the material itself really that big a factor or, is that more opinion based?

Its the same exact material and manufacturing process except DOM has one more step. DOM starts life as HREW and then is Drawn Over a Mandrel cold. This works the weld seam out of it and brings the OD/ID down to a more specific tolerance.

As far as actual strength Id love to see some facts.

 

[Deuling]

Its the same exact material and manufacturing process except DOM has one more step. DOM starts life as HREW and then is Drawn Over a Mandrel cold. This works the weld seam out of it and brings the OD/ID down to a more specific tolerance.

As far as actual strength Id love to see some facts.

Only thing i see that doing is maybe making it a little less prone to denting. And thats what ive read to.

But real structure wise? Facts vs opinions would be cool etc.

 

[sreidmx]

Here adam check this thread,
http://www.pirate4x4.com/forum/gene...33-tubing-strength-chart-weight-per-foot.html

there is a chart that shows the strength.

From what I have been told because DOM is much more accurate with its thickness and more consistent its able to withstand much more force, think about this, your truck endures the most force at 45 degrees falling from the sky and hard on the brakes. that is when the most energy is transferred into your suspension. now if you fling the truck across the desert aka flipping end over end which can happen easy because of the short wheelbase, you will amplify that quite a bit, its really hard to quantify because you cant measure it like you can a jump. remember F=M*A, I wouldn't for one second worry about the state of the truck, the by product of having that cage is the stiffness it adds to your chassis, blazers are more rigid by proxy of them not having a bed to flex. I might be overthinking this but the main reason you should be concerned with a cage is to protect yourself and your occupants. its one area I refuse to compromise on mine because Ill have my wife and kid. and you don't know when something is going to happen.
With that said you should consider that chart and it demonstrates how DOM can be twice as strong. another consideration is Score requires 1.75 inch tube up to 5000lb and 2 inch beyond that. Stringers added to take up the open space regardless of placement is only going to be as strong as the pipe its made from. If you have a long straight run and throw a triangle in there made from subpar pipe you will compromise the strength of the cage, remember the entire structure relies on itself to maintain rigidity and strength, Id rather have spend twice as much to "know its not going to bend or rip in a place because I wanted to save some cash.
Dude trust me I get it, you want to maximize your expenditures, Im in the same boat and trust me I try and make every dollar stretch but safety isn't that place to do it. Helmets only help so much if the whole structure caves in..

Here is another chart of yield strength of tubing, http://engineershandbook.com/Tables/steelprop.htm

if you search you should be able to estimate the force your truck would encounter in an impact, say 50 mph complete stop, then add a safety factor of 4-5 times that and Id say that's safe. For example I have strength analysis for a 4 link for a early 70s chevy truck according to my uncles calcs(20 + years in suspension engineering) he tells me the lower links see 45k lbs of input force in the scenario I described above.

The DOT require 4/5ths safety factor..

ps sorry for the novel.. and no I don't know everything so If I get something wrong please correct me.. just trying to be helpful.

 

[Deuling]

Good post.

The first link doesnt have any links though to a real study.

The second link goes to show that there are many different types of tube properties from the mfg processes. And someones opinion on why one is better could be way off as the types of cages they may have compared, could have been made out of completely different styles of manufactured steel. Not just dom vs hrew. But the properties of the two.

One big factor I see is the hardness of the steel. If it is softer, it will give/bend easier, if its harder i feel it would tend to break/tear easier.

In no way am I trying to say HREW is better. Im just not sure if the examples i have seen, are a fair comparison.

 

[blazinzuk]

I have actual measurements in a manual somewhere ( in storage) DOM is in fact stronger than HREW. I don't remember exactly but around 20% in every aspect. Chro moly is around 15 to 25% stronger than DOM. Race sanctioning bodies do come up with rules randomly and you are typically allowed to use a thinner wall tube when upgrading it. For instance in SCCA street class under 3500 lbs you must use 1.5 " .125 wall HREW if you upgrade to DOM you can use .095 wall. Chro moly you can use .083 wall. Step up in weight and it's typically just a bigger tube size. There are also specifics about how to build a cage.

I wish I has specifics for you Adam. I have also proved unscientifically it is stranger with a 10 lb sledge. Also if you have ever hand bent it it's obviously better steel. Or at least has more resistance to bending

Some rule books I have looked at to build cages actually gives the reference to the proper engineering specs. If you want your steel supplier should be able to supply specific strengths

 

[Deuling]

I did notice it was harder to bend.

Brett ordered dom for his tube buggy build. We really didnt know as we had never messed with tube before, but they had given him hrew at dom price ( he later on bitched and got a bunch of money back. So half his tube is dom, half is hrew).

 

[rdn2blazer]

In building my cage I was going to use DOM period. I knew I could save money using HREW but just did not care about the extra cost. Put safety @ #1 priority first period. Built my cage to at least Score rules for size tube/vehicle weight, head clearance, seat belt height etc. My welds ain't always pretty but I trust they will hold up just fine. It's personal choice as what to use. What's your priorities are. I didn't care about saving a few bucks. For me, I will always use DOM in a cage. If a buddy wants me to build a cage use HREW, no problem. It's WAAAAY better then nothing at all. Dune jumper = DOM tube. Just my .02 cents

 

[Deuling]

I hear you rob.

But im not doing it do be a jumper. Im a pretty defensive driver. Ill run a lap a few times slow every time. I stop on top of the hills, and figure out my lines.

Im not the guy going to the wood all over. Ill run it many times before im comfortable putting it down.

Also I dont go stupid with passengers.

As ive said, if im gonna be dumb, people are getting out of the rig.

Hell ive ran this thing harder than it should have with no cage. I think any cage at all will be 100% safer.

 

[63chevyll]

I agree with Wade. DOM around the driver at min, the all x and straights HREW should be be fine for what your doing. And like others have said, the design is most important. X, TRIANGLE where possible.

You knw what helps me want to build strong cages......go watch some YouTube crashes and rethink your design until you are satisfied with it. Watching that stuff always makes me want to build a stronger cage.