tube chassis: bio-max?

what size and wall thickness for mild steel is minimum? i was thinking 1.5 x 1/4 wall but maybe 2 inch diameter would be better. any help is appreciated.

That is like asking what tire should I use. What size rim do you have? What do you want to do with the car? blah, blah, blah.

What are you trying to do do with the truck?
What kind of truck?
Is weight a concern?
Do you know how to use tubing?

The last question is important. If you know how to set up tubing properly you can cut the tubing size way back. If you don't you need to use thicker tubing to make up for the improper loading of the tube.

I don't mean to sound harsh, but I get asked this a lot and it is a good question, there is just not a simple answer. If you want to stay safe, if it's a mini use 1.5" x .120" and if it's a full size use 1.75" x .120"

awesome i appreciate your help. i somewhat know how to use tubing, i know that triangulation is key. and its a actually a midsize truck. so i'll just go with the 1.75 x 0.120. weight is something of a concern because i dont want it to be overkill on weight but i dont want to skimp on strenght of the frame. its a v8 dakota and i plan on runnin 20 and later 22's. but i also will have a project mighty max and in it's case i will use 1.5 diameter.

Sounds good. If you want to save some weight without too much concern, run the 1.75 x .120 for all of the "primary" tubes and use 1.5 x .095 or .065 for triangulation. Those tubes should be only loaded in tension and can be quite thin.

max, if i pay you millions of dollars can i come and learn and work in the school of cool??? i want your knowledge!

You're going to pay me to work for me? Dude you are in! When can you start? How's $400 a week sound?

thats including rent to sleep in the garage? ill get my plane tickets...