I have a 16ft trailer I took in trade for a job I did, that just isnt up to snuff for what I use it for. Its a 7k lb tandem axle, factory built, car hualer made from angle steel. At the time I got it, I didnt really want it, but it beat getting stiffed on a job, so I floored it and have been using it to hual my small tractors around. 1500lb tractors +attachments, so its never been over loaded GVW. The problem is it flexxes so much it is breaking into. Its also about 2ft shorter than it needs to be. I am considering building a longer trailer and just using the axles out from under the old one. I dont want to sell the old one to anybody, its just to far gone. I want to keep the trailer as close to the ground as possible but dont want to use angle to build it with. I was considering 2x4x3/16 rectangle tubing for the frame, but the cost of steel has me wondering if I might be just as well off with 2x4 channel framing and using 2in channel for cross members so I can set the lumber floor down inside the frame. Anybody have any thoughts on this? I think the reason the other trailer isnt holding up is because I hual two 1500 lb tractors at the same time, (one on each end because thats the only way they will fit), and the angle iron cant stand the stress of the bounching of two seperate peices of equipment, where as one 3000lb tractor would probably never give any problem. Anyways, rectangle tubing or channel iron, what do you think?