Rollcage Design/materials

doddzee · Post by **doddzee** » Wed Sep 06, 2006 8:40 am

Are there many events that you need to worrie about meeting the 4 point NZFWDA rules anyway? Surley if you meet ORANZ it will be enough

nz4x4 · Post by **nz4x4** » Wed Sep 06, 2006 8:41 am

I am going to be doing a mixture of ORANZ events and winch comps. but i agree if i can compete in ORANZ they should allow me to compete in winch comp's

Thanks for the help guys, although i dont suppose that one of you could take a picture of your mounting points and send them to me?

doddzee · Post by **doddzee** » Wed Sep 06, 2006 9:08 am

Pics of mine wont be any good to you i have a 4 point that bolts to the chassis behind the cab then depending if i end up competing next year and building a complete cage im goin to run the front legs up inside the cab along the roof line and through the cab above the rear windscreen then join to the top of the outside hoop with a Twin Lug connection.

nz4x4 · Post by **nz4x4** » Wed Sep 06, 2006 9:13 am

oh ok, thanks mate

GQTROL · Post by **GQTROL** » Wed Sep 06, 2006 9:15 am

Email sent.

lilpigzuk · Post by **lilpigzuk** » Wed Sep 06, 2006 10:03 am

Are Exo cages allowed in winch comps??

doddzee · Post by **doddzee** » Wed Sep 06, 2006 10:07 am

Yes they will be but must meet ORANZ Specs. Ive been told you will have to reinforce your sliders fairly heavily.

nz4x4 · Post by **nz4x4** » Wed Sep 06, 2006 4:31 pm

As doddzee said they are legal, although Sooty says he is conserned about the lack of diagonal bracing and is looking into it.... not sure if anything will come it though.

doddzee · Post by **doddzee** » Wed Sep 06, 2006 4:40 pm

On a full body 4wd i can see how thats a problem but i dont think i would be on a ute as it can be build the same as an internal but it would have longer spans between joints.

As i understand it the CCDA doenst allow them as they see there still being a chance that the roof can come in on you.

nz4x4 · Post by **nz4x4** » Wed Sep 06, 2006 5:11 pm

Yea, i was only speaking for the full bodied trucks. on a ute/cab it is the same as you said.

nz4x4 · Post by **nz4x4** » Sat Mar 03, 2007 8:20 pm

A bit of an update.

I have just started collecting materials etc to build my cage.

It is going to be an external 6 point built to ORANZ specs made out of 38.1mmx2.5mm MANZ approved rollcage tube. (I have been told that this is an approved substitute to 32NB medium wall steam pipe)

One the cage constuction gets underway i will post pics along the way so others can benefit from the research i have done.

JTop · Post by **JTop** » Sun Mar 04, 2007 5:52 pm

Hi NZ
I would be concerned about 2.5mm wall tube on an exo cage on a heavy truck, ie your avatar. It may dent easily meaning a messy cut and repair, and don't some hoops have to be 1 piece.

nz4x4 · Post by **nz4x4** » Sun Mar 04, 2007 6:53 pm

Yes some hoops have to be one piece (B pillar hoop) and it will be.

The cage design will be almost identical to the one steve's truck (monstr) so only the A pillar part of the hoop will be external the rest will be contained in the ute part of the body (the white canopy comes off...). I will also be adding a lot of extra triangular bracing which will further strengthen the cage.

It only has to withstand one roll so as far as denting goes, I am not worried. If a major dent is evident i would just replace that piece.

I appriciate your concern though.

Madaz · Post by **Madaz** » Sun Mar 04, 2007 9:20 pm

Hi there Sam, I would be concerned about using that size tubing on a truck that weights as much as a mq, have you tried to bend any of that tube and compared it to steam pipe or seamless line pipe?its a lot softer
Medium walled steam pipe would be 3.2mm wall minium.
Would recommend you ring Brian Howat in Wellington and have a talk about the tube you are wanting to use- he used to work at Southwards and Knows some interesting facts about that tube and why the 4wda wont endorse it for use

Cheers

mudhaw · Post by **mudhaw** » Sun Mar 04, 2007 9:47 pm

ORANZ Rules are out of date and soon to be changed, they only allow 2 types of pipe for roll cages and roll cage pipe and cromolly are not in there. They are beter and will be passed at scrutineering but are not in the rule book. They must have a chassis mounted rollover hop and be a 6 point
If you want to see some cages that comply come to the Extreme park on the 10 of this month (Norwest winch challange) $5 adults kids under 12 free.

Dion

nz4x4 · Post by **nz4x4** » Mon Mar 05, 2007 6:49 am

Cheers Dion, I'll be up there to have a nosey anyway so will have a look at the cages while I'm there.
When you say the ORANZ rules are soon to be changed, do you mean that they are going to alter the approved materials? and other parts?
Can you remember what size chromo was used on Shirmin?

Madaz, I already know all the specs on the semi-bright tube and have done some tests on it. But cheers all the same

nz4x4 · Post by **nz4x4** » Wed Apr 11, 2007 10:35 pm

I have pretty much finished my design. Obviously it has further bracing from the bullbar at the front which will strengthen the A pillar

just thought i would post it up for people to have a bit of a look

doddzee · Post by **doddzee** » Wed Apr 11, 2007 10:40 pm

Exo??

Looks good, why not just go for a single main hoop? Saves a fair bit of mucking around

nz4x4 · Post by **nz4x4** » Wed Apr 11, 2007 10:45 pm

Yea Exo, using a double main because it will provide some extra strength (some people have concerns about strength as you can see above)

Some things like sliders, bullbars, twin lug joints, mounting plates etc have been left out of the CAD drawings.

4WDbits · Post by **4WDbits** » Thu Apr 12, 2007 9:10 am

I think all those curves in the bottom of the main hoop legs will seriously weaken the structure, you might need 3 main hoop bars to regain the strength of a single straight leg. I think most rollcage standards exclude bends in the main hoop legs, allthough feel free to correct me on that one as I don't have the manuals in front of me.

nz4x4 · Post by **nz4x4** » Thu Apr 12, 2007 10:23 am

I was thinking about that myself. From what i can remember the rules generally say that the vertical part of the main rollbar must be as straight and as close as possible to the interior profile of the bodyshell.

Obviously i have a problem with the wheel arch getting in the way. Any ideas on how to get around it? (need to be able to put a twin lug joint under the body to attach to the chassis.

doddzee · Post by **doddzee** » Thu Apr 12, 2007 10:57 am

Cut the back off it :wink:

It seems as though your trying to make what should really be an internal cage into an external. How much room is there from the back of the b piller to the wheel arch? How far along the wheel arch does the main hoop need to be? If you remove one of the bends and cut/modify a section of the wheel arch will the tyre foul the main hoop?

You could bring the main hoop outside the body to the sliders like on many of the other winch trucks.

nz4x4 · Post by **nz4x4** » Thu Apr 12, 2007 11:58 am

Cutting the back of is at a later date....

There is essentially no room from the back of the B pillar to the wheel arch. I may get away with cutting a hole through the wheel arch and running the hoop straight down to the chassis.

If i bring the main hoop out and down to the sliders, how would i beable to get a diagonal brace in?

doddzee · Post by **doddzee** » Thu Apr 12, 2007 12:29 pm

Good point, it would mean cutting a hole in the body and making the cross braces bolt in. Would be pretty ulgy though.

There is a red hilux wellside in 4x4 action mag in the norwest winch challenge photos it has an exo where the main hoop goes down to the sliders you could look into how they have done it.

If you are dead keen on keeping the rear id go for a nice fitting internal.

nz4x4 · Post by **nz4x4** » Thu Apr 12, 2007 12:38 pm

Internal is basicaly out of the question because there isnt enough head room. I would have to drop the seats too much to get the 90mm clearance.

I'm not against chopping the back off but I dont have the money to respray it once it is done (It will be done at a later date)

I might ask steve if i can have a look at his truck. It is a similar set up as I remember. And i will check out 4x4 action

Cheers

monstr · Post by **monstr** » Thu Apr 12, 2007 2:56 pm

Hi Sam Give me a call and well make a time to come around and check out how mines done...Steve

doddzee · Post by **doddzee** » Fri Apr 27, 2007 2:26 pm

How is that main hoop design coming along nz4x4?

Worked out how your going to make it work?

nz4x4 · Post by **nz4x4** » Fri Apr 27, 2007 5:09 pm

Yea I have sorted it out. I am going to stick with the existing design but im not going to attach it to the body, instead i am going straigh through the floor to the chassis. I am just drawing out all my bends on big pieces of card ready for bending. First job will be the sliders which will be to be heavily reinforced.

I am also going to run the cage by ORANZ to get the big OK