car frame

The box frame is going to be the strongest, followed close by tubular, (depending on the wall thickness, too thin and bets are off) then the c-channel.

The weak points are going to be your welds and your costs to be much higher then a casting. But if your not concerned with cost... box !

thanx for your input, my project is to build a 3 or 4 wheeled electric vehicle, i have children so safety is primary concern.

you mentioned tubing dia. & thick.. do you know min. thick. & dia. that i should use? - i've seen 1" & 1¼".

?@ welding which is best/strongest MIG, TIG ...?

thanx again

Dia and thickness will depend on stress in the tube. Without seeing the design, I can't make a serious suggestion. Usually, in electric vehicles, weight is a major factor so you don't want to use anything heavier than you have to.

If this is a "fun" car for your family and not something you want to make a number of, you could use 1" x 20 Ga., then see how stiff it is when complete. You can then double up or replace tubing as needed.

DO NOT use this method if you need crashworthiness, though. Get an ME to do a stress analysis for you.

DO NOT use this method if you need crashworthiness, though. Get an ME to do a stress analysis for you.

crashworthiness / occupant safety is primary concern, so i guess i'll need to hire a ME.

is there an economical way to hiring an ME? or maybe getting that info from the Dept. of Transportaiton or ... ?

Thanx for your input

I would try the nearest engineering school. You might get a master's candidate to do it as a class project.

great idea thanks again!

Race cars use tubular chassis.

thanks for your response, i thought i'd heard that, are they typical tubular steel or some special steel or ?? i wonder if it's like something i could buy (typ. individual comsumer purchase) or is it their specially-engineered design ? because i've heard boxed frame is the strongest. thanks for your intput

One race team claimed they used unobtainium for their tube frame. Most use aircraft quality tubing. I suspect the factory-sponsored Porche 917 used titanium, but they had a nearly unlimited budget.

can somebody suggest me wat is the criteria to slect side meber and cross members for min truch frame