Hopefully someone can help me with this. Regarding the tubing dimensions for roll cages, the SCORE rules specify the same size for chromoly and DOM. What's the point of using chromoly if the wall thickness requirement is the same as DOM?

It's the rules, that's why..

Why use chromoly verces DOM??? STRENGTH Chromoly is stronger in lighter thicknesses. DOM is still mild steal with out a seam, thats why you rarley see a buggy built out of DOM.

I see lots of buggy's built out of dom...

Chromo is only a good thing if you manage to normalize the chassis after welding (ignored 99% of the time)

The benefit of chromo is being able to build lighter weight materials just as strong.. As long as you do it right..

Dom still has a seam, it is just hidden ;)

How can chromoly be a lighter than DOM if you have to use the same wall thickness for both? The only reason I see to use chromoly is that you get the same strength with a thinner wall, but if you have to use the same size of tubing no matter what type you use, there weight advantage.

In a class 11 I think this debate between DOM and 4130 is valid and it is true that equal size tubing is the same weight. Since there is limited quantities of non-spec'd tubing, the weight savings could be minimal. I can only think of about 12-15 feet of tubing that I would substitute 0.065\" from 0.095 which equates to only about 7 lbs.

Also, some parts on the car I'm going to build will use some 1.00 x 0.095 and that is about half a pound lighter per foot and that would include a total of around 20 feet.

All in all, I predict that by using thinner walled 4130 when appropriate would only result in about 20-30 lbs. on a well built class 11.

The tensile strength is better with 4130 so if you consider using 0.095 for your base bars instead of DOM 0.120 wall you'd save another 8 lbs or so.

That's my 2 cents, crazy thoughts from San Diego (whale's vagina). What do I know, I'm just a stupid surfer rambling on the internet.

michaelbrenner wrote:


Yep, If I were really wanting to shed 20 lbs off of my car. I would go on a diet :D

If I lost 30 lbs. I wouldn't be strong enough to change a tire on the car. We will be the jockey crew. 5'6\" or less, 165 lbs or less......hahhahaha. There's your weight savings, just don't ask us to push our own car out of a sand wash or similar.....

michaelbrenner wrote:


The telephone book suspension seat??? :D