strongest tubing

[jonnyslick]

... so this question was spurred from another thread i was reading over on desertrides.com ...

what is (if money is not a concern) ...

1. the strongest/best tubing for cage
2. the stronges/best tubing for bumpers, engine cages, and bed cages

just curious :p

[BajaBronco13]

Hey Jonny,

Great questions. I'm curious to find this out as well.

CP

[jonnyslick]

I guess a more simple way to put it is, "what do Class 1's and TT's use for their cages and/or chassis".

[OldGreen]

4130 chromoly

[Dust]

molecularly stabilized unobtainium with a flash of kryptonite and a coating of transparent aluminum....
<O:p
4130

Dust<O:p
<O:p

[151FAB]

I would argue that the best tubing for bumpers and other first defense/offense protection might not fall under the same category as strongest. We could learn a few thing (some already have) from the major automakers and other auto-sports buy including crush zones into our designs. Making your bumpers, nerfbars, tire racks, light bars, etc, etc, out ERW tubing instead of 4130 or even DOM might absorb some of the energy in a crash or impact with other racers or immobile objects on the course. It also might lessen the damage done to others in a wreck on the highway. Building these parts of your vehicle as bolt-on, consumable sub-assemblies and using a more pliable material might be the best and yet less than strongest solution. PS: Its cheaper too...

[jonnyslick]

so where does DOM fall into the equation?

[Dust]

Most DOM is...
Welded mild steel that has been Drawn Over a Mandrel... OR DOM
<O:p

[151FAB]

A byproduct of the "drawn over mandrel" process is an increase in the tubes strength via an improvement in its mechanical properties and concentricity.

A cool web page that explains the DOM process: http://www.ptcalliance.com/dom/dom.asp

4130 is about 20% stronger than DOM for our purposes and contrary to popular belief it has greater elongation as well.

1018 Mild (low-carbon) steel
Minimum Properties Ultimate Tensile Strength, psi 63,800
Yield Strength, psi 53,700
Elongation 15.0%
Rockwell Hardness B71
Chemistry Iron (Fe) 98.81 - 99.26%
Carbon © 0.18%
Manganese (Mn) 0.6 - 0.9%
Phosphorus (P) 0.04% max
Sulfur (S) 0.05% max



4130 (Chromoly) Annealed Alloy Steel
Minimum Properties Tensile Strength, psi 81,200
Yield Strength, psi 52,200
Elongation 28.2%
Rockwell Hardness B82
Chemistry Iron (Fe) 97.3 - 98.22%
Carbon © 0.28 - 0.33%
Chromium (Cr) 0.8 - 1.1%
Manganese (Mn) 0.4 - 0.6%
Molybdenum (Mo) 0.15 - 0.25%
Phosphorus (P) 0.035% max
Sulphur (S) 0.04% max
Silicon (Si) 0.15 - 0.35%

[OldGreen]

I would argue that the best tubing for bumpers and other first defense/offense protection might not fall under the same category as strongest. We could learn a few thing (some already have) from the major automakers and other auto-sports buy including crush zones into our designs. Making your bumpers, nerfbars, tire racks, light bars, etc, etc, out ERW tubing instead of 4130 or even DOM might absorb some of the energy in a crash or impact with other racers or immobile objects on the course. It also might lessen the damage done to others in a wreck on the highway. Building these parts of your vehicle as bolt-on, consumable sub-assemblies and using a more pliable material might be the best and yet less than strongest solution. PS: Its cheaper too...

The strength difference isn't so much that you can even use this as an argument. . .EREW is pretty tough stuff. Crumple zones and such are engineered to be weak links and would use thinner material that was shaped so that it would bend like an accordian to both absorb impact and NOT enter the passenger compartment. The trouble with this idea in any kind of endurance application is that you might want to run into something and keep on going. It would be pretty tough to do that if your tire carrier just crumpled through your radiator.:D

BTW. . HI!! I'm OG. I used to race short courses years ago, I have been off-roading all of my life, and I am getting ready to put the helmet back on. It will probably be in a class 3!!! More to follow and /Hijack off/

[Dust]

Hi Old Green are you related to Red?:D

Relevent to thread...:)
Oh and I agree on your point.

[jonnyslick]

so in a nutshell ... 4130 chromo is the way to roll?

[Dust]

so in a nutshell ... 4130 chromo is the way to roll?

Yes... IF you need it.
And no... IF you do not.

In the wind

[3amigo]

4130 seems to be king. I wont be using it for any of my parts for a few reasons. I can weld dom with my mig with no problems, 4130 is a bit trickier to get right. One of the big arguments that I here with 4130 is that in a crash you might bend a few tubes, but the rest of the car should be ok. In a class 3, based on a production car, if you crash it that hard you are probably going to be starting from scratch again anyway.
Score requires the same diameter, thickness regardless of 4130 or dom, so there isn't a weight penalty for dom.
And finally there are dom varieties that come really close to 4130. These go by different names, but tuff dom, dom 520 are a couple that come to mind.
Lots of choices, but right now in desert racing you have 4130 and dom to choose from. crew, hrew, and any exotic metals like Ti are not legal.

[jonnyslick]

Nice thread ... thanks for the posts guys!