stony Posted July 20, 2001 Share Posted July 20, 2001 I know chromoly is lighter then steel but by how much??? is it worth the 300-400 dollar increase over a steel cage(12 pt) i also know it is stronger.... How much stronger. I want to do this right the first time and need as much advice as possible. i want to eventually get into the low 9's ;> and want to make the chassis as strong as possible. anyone ever seam weld there car? does this make a big difference? thanks stony Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted July 21, 2001 Share Posted July 21, 2001 1 5/8" tubing? Chromolly is about 1lb lighter per foot do to the fact that it can be thinner wall for NHRA requirements. NHRA also REQUIRES chromolly to TIG welded NOT MIG welded. Maybe we can get someone who knows their poop well enough to help figure out the next problem. I was speaking with a guy today that said it did not make sense to use chromolly because it would have to be heat treated before it would be stronger than mild steel. How do you heat treat a roll cage after its welded in a car? Well Hunnydo's await, Later. Jamie Deathstar Quote Link to comment Share on other sites More sharing options...
Drax240z Posted July 21, 2001 Share Posted July 21, 2001 Well chrome-moly is actually the exact same weight as mild steel. But it is stronger, and therefore rules allow you to run a thinner wall thickness on chrome-moly cages than they do with mild steel. I believe it was john coffey (I could be wrong) that told me somewhere that he saved 45lbs by going with a chrome-moly cage over a mild steel one. I've seam welded parts of my car, but haven't driven it yet since then. I doubt it would make a huge difference by itself though. Quote Link to comment Share on other sites More sharing options...
Ray Posted July 21, 2001 Share Posted July 21, 2001 Crome Molly is lighter but it also is very rigid. It doesn't bent well.... the reason most race car builders us mild steel is it bends and absorbs impact in a crash better. Now for the question about heat treating Crome Molly... Most shops only aneel the weld joint after the car is complete due the the weld joints getting brittle. Crome Molly is great stuff for suspension componets and stuff that has to be strong and light, but for roll cages DOM mild steel works great just ask the NASCAR boys that is all they use.... Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 22, 2001 Share Posted July 22, 2001 Yeah, Ray nailed it. Thats the problem with welding it, it does need some special care with heat treating and would require Tig'ing. Its ghastly expensive and to save that sort of weight and the expense of having it professionally welded, I'd have to really wonder if it was worth it. If it was a total racecar and weight was a supreme concern I'd think about it, otherwise I'd put in mild steel and not lose any sleep at all about it. Regards, Lone Quote Link to comment Share on other sites More sharing options...
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