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Mykal
05-05-2010, 08:53 PM
I went to get some prices on some cage work for my XJ. I explained that I wanted to use HREW or DOM 1.5"x.120 for the cage. He told me that if I use DOM that 1.5"x.095 would be more then enough and he wouldnt use .120.

I was thinking he just didnt want to bend .12 but he has an electric bender and said it would bend it with no problem when I asked him if that was the reason. So there really isnt any extra work for him that I can see. He hits a button, it bends.

He claims the difference in weight is the reason for it.

So... is DOM .095 too thin?

13below0
05-05-2010, 09:15 PM
Are you set on 1.50 od? the larger the od the stronger it is. So maybe go to 1.75" and 0.95?? Personally I would do .120 on the A and B pillar and the 2 outside tubes running along the side of the jeep in .120, then you could mix in some 0.95x 1.50 for the other pieces. Just some thoughts.

Mykal
05-05-2010, 09:25 PM
Im not set on 1.5" at all. I just figured it would be a bit cheaper and save weight instead of using the 1.75".

justin'sbig7
05-05-2010, 11:42 PM
last time i bought tube it was $4.50 a foot for either 1.5" or 1.75". both .120 wall dom. hrew was like 3.80 a foot wich in the long run is neglegable. i agree with jason, .120 wall for everything structural, and if you must use .95 wall or hrew, use it for braces and supports, not in mains. i personally use it for everything.

people are getting a misconception lately and i think it stems from this: .095 wall CHROMOLY tubing is approved and used a lot for use in racecar cages. it is stronger than .120 wall mild steel tubing, but people see .095 and think its good.

with your jeep being a unibody, i would think that 1.5" would be enough as it will be an addition to the support as opposed to your only protection. this is completely up to you and base it upon your research.

i have the weights in my bendtech program and can see the weight of the cage as i build.... the difference is slight unless you start getting more than 100' of tube in a cage

*these are my opinions, research racing sanctioning bodies such as king of hammers rulebook to get the best idea as to what you should do*

justin'sbig7
05-05-2010, 11:46 PM
i also would question the guy about his bender, make sure its a good machine and not a pipe bender that he sticks tube in. the quality of bend is critical in a cage

Mykal
05-05-2010, 11:55 PM
Good advice. Thank you.

They build dirt track chassis so they are not new to this. I just dont think they have done this type of application.

OverkillZJ
05-06-2010, 12:01 AM
...Dirt track chassis =/ to landing on the rocks and rolling over a few times. It's been a long time since i've researched cages, but I've never heard of anything less than 1.75 / .120 wall being approved for, well, anything, unless it was chromo throughout (which is pointless for a hobby rig.) I can't imagine why this guy wouldn't go with .120 wall 1.75 or something similar, as far as I know it's pretty much standard unless it's some tiny custom rig.

EDIT: keep in mind, I've only put the buggy over a few times, the first time was hard enough to almost hurt my passenger, and that was DOM .120 wall 1.75 following the line of the stock A pillar. That was a flop; not a roll.

dan58
05-06-2010, 09:07 AM
Definitely stick with 1.75x.120 tube for the whole thing.

13below0
05-06-2010, 12:06 PM
Dan can you set me in the right direction for rules for we rock, koh type events? We build race cars so 75% of the stuff we do is cro-mo 1.625 x 0.95 for the main structure and then in can be down to 1" I need to take my own advice on this. I think people need to design better and use less tube.

justin'sbig7
05-06-2010, 12:25 PM
Dan can you set me in the right direction for rules for we rock, koh type events? We build race cars so 75% of the stuff we do is cro-mo 1.625 x 0.95 for the main structure and then in can be down to 1" I need to take my own advice on this. I think people need to design better and use less tube.


I agree and am guilty of this myself. There's a few things I did on mine that used more tube than needed to achieve the look I wanted. Strong and simple is the best medicine.

SirFuego
05-06-2010, 12:57 PM
Dan can you set me in the right direction for rules for we rock, koh type events? We build race cars so 75% of the stuff we do is cro-mo 1.625 x 0.95 for the main structure and then in can be down to 1" I need to take my own advice on this. I think people need to design better and use less tube.

What kind of weight are we talking about for race cars? Keep in mind that full-bodied rigs like an XJ will be over 5000lbs with cage, long arms, big tires, big axles, etc.

I agree that shapes (i.e. proper design) are a better way to gain strength (and of course save on weight), but when you are talking about heavier vehicles, you need to build it with stronger materials.

For comps:

Anything over 3200lbs in KOH needs at least 1.75" .120
(Section 19 for the roll cage and tube size)
http://www.kingofthehammers.com/rulebook.php

We Rock only requires 1.5" .120 (although only 1.5" 0.095 is needed for the unlimited class)
http://www.werocklive.com/rulebook.php

dan58
05-06-2010, 03:54 PM
Dan can you set me in the right direction for rules for we rock, koh type events? We build race cars so 75% of the stuff we do is cro-mo 1.625 x 0.95 for the main structure and then in can be down to 1" I need to take my own advice on this. I think people need to design better and use less tube.

www.kingofthehammers.com has a link to the .PDF rulebook. In general, all trucks are going to weigh north of 3500 pounds due to large fuel tanks, spare tires, spare tools, etc. The key is the proper USE of the tube as much as anything. Jungle gym cages aren't any stronger with all of that tube.


I agree and am guilty of this myself. There's a few things I did on mine that used more tube than needed to achieve the look I wanted. Strong and simple is the best medicine.

One problem many people don't see when building a cage is that the weight is the highest point in the chassis. However, you need 6" of noggin clearance too.


What kind of weight are we talking about for race cars? Keep in mind that full-bodied rigs like an XJ will be over 5000lbs with cage, long arms, big tires, big axles, etc.

I agree that shapes (i.e. proper design) are a better way to gain strength (and of course save on weight), but when you are talking about heavier vehicles, you need to build it with stronger materials.

For comps:

Anything over 3200lbs in KOH needs at least 1.75" .120
(Section 19 for the roll cage and tube size)
http://www.kingofthehammers.com/rulebook.php

We Rock only requires 1.5" .120 (although only 1.5" 0.095 is needed for the unlimited class)
http://www.werocklive.com/rulebook.php

I wouldn't even look twice at WE-Roc's rules. Those trucks are build with absolute minimal weight. Their rolls are typically slow flops, rather than a 70mph cartwheel across the desert.