I need info on engineering with sq tubes. I designed a SWB bent with 2"x .065" sq and 3/4" x 1-1/2" rectangular for the rear forx.....this tubing is very strong and may be strong enough for 500lbs....this would be good, I realy want to know what I'm getting my self into before I do it.

it's just a straight shot back to the forx from the crank. 20 and 26" wheels.

I brainstormed this formula, is it valid?:

psi devided by the wall thickness, times 2, times the depth, devided by the leigth between pivot ponts (or should this be the area of the arc between the pivot points) divided by maximun gravity???

Well I guess you'd b happy to know that square is 33% stronger then the equivilent diameter round tubing. Thats all I know and thats why Im using it of late. Also, its easy to weld due to the flat surfaces.

I know it is stronger but it also has about 22 percent more material, so it is heavier. I'm not sure about torsional loads and how they compare with round tube.

Just a thought

Bob