Some tube questions.

[ricola]

It basically comes down to the fact that it has more cross sectional area further away from the Neutral axis (this is the part of the tube that is neither stretched or compressed).

Rich

[kdanie]

4130 chromemoly can be mig welded effectively, the biggest problem is cooling it too fast-that's where the brittleness comes from. If you require a very light weight car and can afford the chromemoly it's good stuff and welded correctly will not "shatter". Mild steel is considerabley cheaper, easier to get good welds on and with the correct dia. and wall thichness is more than strong enough for anything you might like to fab.

What do you plan to build?

ken