Roll Cage tube size

[Deuces13]

I'm re posting this topic from safety. The last response to this rule was in 2022.

As I read the rules cage tube size is 1.65 .095 wall for 6130 molly or 1.625 .120 wall DOM  for anything over 175 mph.
I have plenty of 1.625 .083 on the rack because this is standard for NHRA up to an 8 second car

Stainless mentioned using 1.75 .125 Dom in the last post on this that I could find back in 2022. This is not in the 2025 rule book. So My question is can 1.75 .125 wall DOm be used. I also ask this because I can't find 1.625 .095 wall molly or 1.625 .120 wall DOM in Florida or from my suppliers.
1.75 .125 wall is easier to find . I never bent tube with a .125 wall thickness on my JD3 bender so it will be interesting.
I don't think my body will survive the impact a 1.625 .083 cage wont survive. I'm sure there is a reason for the requirement hopefully from experience.

I did reach out to Kiwi Steve and will post what he tells me on this . I don't know who else is the go to on it.

AJ
Stay Salty Racing

[Stainless1]

Yes you can use 1.750x.125... the 1.625 is the minimum size... if you look at strength the 1.75 is stronger. 

[37 ROADSTER]

  Call Joe Timney at Delaware chassis works, he is in Florida and can answer all your questions.

[Deuces13]

Ya that makes sense seeing its larger lol. I definitely over thought that one.
I did find 1.625 .120 at TW Metals. If they have it in stock that?s what I will use.
Thanks
AJ

[racergeo]

  15/8 mild steel is the minimum but 13/4 DOM is 40 percent stronger  according to my supplier. At least on the main cage hoops it is false economy to pretend like your life isn't worth it. When you over build it for safety the tech guys appreciate it.

[panic]

"seeing its larger"

That's not the point, 1.75 / 1.625 is only 7.7% larger.
It's how it's larger that makes the difference.
An OD increase is by far the greatest change (not material or wall thickness).

[1leg]

1.75" x .120 wall DOM steel is what is recommend in landspeed racing. If you plan to run 1.625" dom steel you will need to run .134" wall. The tube will get thin on the outside of a bend and if the measure the tube on a bend it will read less then .120. same thing with 4130 you will want to use a thicker wall.

Best to go larger then you need, the extra weight is not a concern.

[jacksoni]

Remember, weight, generally speaking, is your friend, in contrast to drag racers where sometimes every ounce gets counted. Don't bother with the thin, small diameter stuff. Your neck is more important than those couple of pounds.