Roll Cage

[C4Bird]

I finally recieved my tubing bender and am getting ready to bend up my roll cage next week. I ordered a 1 3/4 die to do this with the bender (a little on the large side I know, I have other things for it as well). What is everyone's opinion on roll cage metal and size? The rule book for NHRA states 1 5/8 .118 mild steel minimum, so 1 3/4 .120 mild steel should work right? I would buy a smaller die set and go chrome moly, but I can't afford the welder and having a chrome moly cage installed around here is a couple grand!! I plan to do a couple of track days a year and a couple 1/4 mile days a year as well. What do you guys think?

-Nate

[Ralph LoGrasso]

I would check with every sanctioning body you plan on running with, just to be certain. I'm not sure if you ever plan to do top speed events or things like the SSC or Pony Express, but most ORR tech is stricter than NHRA. I think most ORR bodies want 1.75 .124 wall or something around there.

[Matt@RFR]

Nate, listen to Ralph. It's definetely worth the time to do the research. Other sanctioning bodies rules will also outline certain bars (and their placement) in the cage, as well as bulkhead material and thickness, battery placement, minimum ride height, and on and on.

Concerning cage material. Yes, NHRA's standard is 1 5/8" x .118" DOM, but it's where they sonic test it that's the trick. They test all the tubes on the outside of each bend...where the wall has been stretched through the bending process. You need to use .134" wall to meet the .118" wall rule! That's what I use, and my friend's chassis came within .002" of failing on one bend!!!!

[quadfather]

it also depends on what type of mild steel you use most companys use c.r.e.w.(cold roll elec weld) or h.r.e.w. hot roll elec weld , to keep the price down theese types of mild steel tend to vary in wall thickness alot .thats why they use .134 wall to meet the .118 min. I would recomend that you use d.o.m. tubing instead . it does cost a bit more, but is formed to much tighter tollerances. and you could get away with .120 wall if wanted to save a little weight. ive been using d.o.m. tubing at my shop for a long time now, and have never had a problem passing cert. with it . plus it bends much nicer than the the cheaper tubing. and it wont collapse as easilly in the bends. www.markowracecars.com

[C4Bird]

Thanks everyone! Ralph/Matt, I am definately going to have to check out the other bodies before I buy! I had a feeling NHRA was a little light on the tech requirements. Quad, I called every metal shop and fab shop in town and none carry .134 wall tube of any type, and none carry .120 d.o.m. They all said I would have to have it trucked in from either Portland or California. The fab shops say they use .124 if they use mild steel if they have to, but say they use chrome moly for nearly everything they build to pass tech. Not sure where to go now. Matt, is it possible to weld chrome moly with a MIG? If so what wire and gas mix do I use? Is it different than welding mild steel? I have access to a TIG I can set up for chrome moly, but only on the weekends. Plus I have to buy everything to set it up and having used a TIG only once, will probably have to teach myself again. This isn't prefered as I would also have to cart my car back and forth (can't leave it in their shop). Never would have guessed with 4 metal suppliers in town, none carry what I need.

-Nate

[Matt@RFR]

That sucks! You can buy what you need from any of the chassis supply places (Chris Alston, The Chassis Shop, S&W, etc.). I can't believe they don't even carry .120" wall DOM!!! That's probably one of the most common sizes around here.

NHRA won't even pass welded tube, so DOM is your only option aside from Chrome Moly. Besides, it looks way better.

For us mortals, welding 4130N with a MIG is not an option. It takes mega bucks and a set of extremely specific parameters to make it work (ala Winston Cup cars).

[quadfather]

nhra will pass welded tube. i think matt meant to say that they won,t pass mig welded c.moly. but like he said , the d.o.m. is still a better choice. i don,t think i have ever seen .124 wall even listed in any of my suppliers catalogs. usually they go from .120 to .134 . where are you from? maybe i can suggest a place to get it . most any race shop could send it ups. up to 8ft. lengths. but that would be a few feet short for a main hoop , truck freight is usually less than a week anyway. good luck!

[Jim Nilsen]

If you read the SCCA rule book and some of the other rule books you will find that for the speeds you might be reaching you will need a 2" main hoop.
I wish I had gone with a 2" main hoop for 2 reasons. 1st is that you can weld the other tubing to it easier and the other is you won't have to replace it if you want to add to the cage later to meet some of the faster requirements. I will have to replace my whole cage if I get over 170mph with some of the rules I have read but if I had the 2" I could just add on to it.It is also only 3-5 lbs heavier yet a lot stronger,well worth the extra weight in retrospect to me.

You will also get a better deal on the tubing from some of the makers of cages because they handle larger quantities of the tubing, you will also get the same tubing that is passed by all of the sanctioning bodies and have a receipt to prove it.

Goodluck on understanding the SCCA rules and what class you will run in. I am sticking to autocross events with them.

Jim Nilsen

[C4Bird]

Thanks again everyone! I am still having a hard time finding what I need locally. I finally got one shop to say they could order .120 DOM, but at $4.50 a foot! This sounds high to me, but having never bought it before I am not sure. I am thinking of ordering and having it shipped to the house. Matt, thanks for the list of possibilities, I 'll look into them on Monday. Quad, I am in Boise Idaho. In a valley with 300 thousand plus people, I figured I could find what I want. Guess this valley needs a couple chassis shops to create the demand, right now there are only a couple all in one custom shops, no specifics. Jim, I was reading through some of the SCCA rules and noticed the 2" rule for the main hoop. I have a couple buddies who want 2" light bars bent up and they are willing to pay me the cost of the die for the work, so I will probably go this way once I figure out how I'm going to get the materials. Looks like next week will not be when I put the cage in, more like next month.... It's all good though, with the delay in materials for the cage I started my 4 parallel link and panard set up for the rear. Should have the 4 links and coil overs done Sunday or Monday. As luck would have it the tranny in my truck smoked itself on the way home form work, so I am going ot have to hold off on finishing the panard set up and put the leaf spring rear back in so I can drive to work next week. I guess life will never be easy.....

-Nate

[quadfather]

c-4 try theese guys for a price. www.marmonkeystone.com there a major supplier with locations across the country. or for the best price try this place first . they will sell to the public, even in small amounts . the dillsburg aeroplane works. (717) 432-4589. east coasts largest supplier of c-moly & dom tubing . they ship anywhere, and sell to all of the race shops. easy to deal with. good luck

[B Schein]

Dillsburg aeroplane works Defiantly carries what you need, but I find dealing with them to be a little odd. John Parsons first told me about them as we both live with in an hours ride from their rural Pennsylvania farm that they run they operation out of. John told me to have every thing I need written on a list before I arrived so I did just this. Once I got there had handed the guy inside the shanty/barn or what ever you what to call it my list. He took list to get the materials but never said a word to me. I was there for 20 minutes at least while he got the tubing and cut to lengths that I specified, but not one word was ever spoken the enter transaction took place in complete silence. John latter assured me that this has happened to him many times there and that ever time after he lives he just laughs about it on his way home.

Other than the silent treatment if you go in person I would say call them they have just about everything you need material wise to build a racecar and the prices are also reasonable.

Brian

[quadfather]

i know what you mean. i wen't there once. now i just call call and talk to charlie. and have my order shiped truck freight .usually takes about a week . no hassles that way.

[C4Bird]

Thanks Guys! I'll give them a call!
-Nate

[Sean-m]

Might try AED Motorsports in Indianapolis, IN. They specialize in metals and tubing for motorsports. They will ship also.

[daryn67]

C-4 Give me a call at the shop here in Ontario, i may be able to hook you up with someone local who cam get you what you need.



Daryn
(541) 823-0844
(208) 405-9640 Cel

[redss86]

04-05-2005 02:34 PM
Ralph LoGrasso I would check with every sanctioning body you plan on running with, just to be certain. I'm not sure if you ever plan to do top speed events or things like the SSC or Pony Express, but most ORR tech is stricter than NHRA. I think most ORR bodies want 1.75 .124 wall or something around there.

Just wandering where I could find copies of these rules/ requirements for roll cage constructions?

Thanks, jmarti81

[MrQuick]

try here for starters http://www.nasaproracing.com/rules/ccr.pdf

[C4Bird]

Thanks for all the help everyone! Looks like I am probably going with a place out of Portland. All of the places suggested all have fair prices, but with being on the west side of the states, the shipping is killer. The more pricey tube ends up being a little cheaper in the long run. Daryn, I'll try and give you a call Monday. If you can find is a little cheaper than the guys in portland, I may be making a trip over to Ontario.
-Nate

[Speed Raycer]

Try my local supplier www.shapirosupply.com Last I checked, 1.75x.134 wall was a little over 3.50 pf for 4 sticks/20ft long.

They ship as well. {edit}They're located in St. Louis Missouri

Which SCCA class are you guys reffering to that requires 2" tubing?