last year when I started gathering stuff for my build, I spent a bunch of time reading and researching what tube to buy to build my cage/ch***is. I ended up buying a stick of 1.75" mild steel plain ol' seamed tube, which at the time I thought was an informed choice. A month or so I showed a guy my build and he told me not to run the seamed tube, saying that in the event of a crash the seam will split, the tube will crush, and I'll get hurt for sure. I'm getting closer to ready to build the ch***is, do I need to rethink and re-buy, or is this guy full of it? (or thinking way faster than I'll be going maybe?)
It won't happen. Believe me..Ive seen many cars that have run that tubeing.. It wont split open or crush as this person has told you.. It's true, Seamless DOM tube is stronger, But in the case of the HAMB cars. Use what you got. We aren't running 7 sec. cars.or 150mph..
What is the wall thickness of the seamed tubing??? I believe also that if the wall is sufficient that you won't have a problem.
QQMoon's right, if it's going to eat at your mind buy the moly, you'll be more comfortable. Also you'll need to tig it. We run seamed .125". Personally I've never seen it split and am quite comfortable with it. And you can mig it. Sorry, that .110" can't be right. I'll look up what we bought this evening. Corrected.
2008 NHRA rule book calls for 1 3/4" dia., .118" wall mild steel tubing. Does not specify DOM. This is for a roll bar, not a cage. Cage hoops can use a smaller diameter tubing. Places like Chris Alston Ch***isworks sell mild steel roll bar and cage kits with .133" wall. This is because .125 wall can sometimes be thinner than .118" or can thin out slightly in the radii when bent. There are mild steel ch***is kits for 7.50 sec. cars so it must be strong enough.
Bobw is absolutely correct. I have built many a roll bar and cage and the 1-3/4"x.118 wall is what is called for but they sell .134 wall because as bobw says it thins at the bend and would not p*** NHRA tech. For a street rod or occasional strip car going 10.99 or slower only a roll bar is required. But its your head!
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