4130 chrome moly vs 1020 mild steel for a chassis

Would anyone like to chime in on the shortcomings and merits of both, for use in a street/trackday car chassis? What would you use?

Randy V

Staff member
Lifetime Supporter
I'd choose mild steel DOM for that use.
A lot cheaper
Easier to bend
you won't need to anneal your weldments
Hi guys......I wondered about this same issue for my suspension links and "A"arms,I have spoken to a couple of sources and the opinions are mixed. The first one was DRB cars in Brisbane when I was there a few months ago and they didn't use moly because they had seen or experienced the moly tube splitting, And another, Is Murry Gorge Engineering in NP (Well Know Modified and Speedway Saloon Car Builder) when I was there Murry was doing some top Links in 11/4" moly and miging the rodend stubs in. When I asked him about having to heat treat the moly after welding, he said he never did and even with his full moly Modified Chassis he didn't do anything after welding and there is a heap of Gorge chassis around that have never fallen to bits. So it a bit of a quandry, My opinion is do what your Budget or your opinion feels is best. My choice was to use a Tubing that is used for racing Motor cycle frames and swing arms by a custom builder here in NP I'm Not shore of the grade code but was told it was a lot stronger than Mild and no where near the Price of moly, Cheers Leonmac
I am using the same material. It's called a crew tube by the metal suppliers I buy from. It's a little harder than the 1020 because it's annealed in it's manufacture. I am getting better with the tig too and learning alot. You can use chrome moly on your control arms but every piece should be of the same material and thickness. It's when you start joining the differnent thicknesses where you get into problems. You need more heat to get a good weld and the thinner materials can become brittle and distort. With tiging, my welder has the power but I am limited to what I can weld by the air cooled torch and electrode size. You have a bit more flexability with mig and regular steel cost wise. If I was using crome moly I would add water cooling to the tig welder and then maybe you could get away without annealing.