Trailer flexing questions

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So here's what I got The trailer started out as a travel trailer. I cut off the tongue and 5 feet off the back to make a 20 foot by 93inch wide trailer. The main frame of the trailer is a 6 inch C channel which is a True channel not press formed. All the cross braces are 2 x 1/4 angle iron. Has two 7500 pound axles with brakes on one axle.  The timing is a 4 x 4 by eighth inch deck square tube that the main rails sit on top of. This trailer is meant to haul a pre-runner and a couple kids quads. My problem that I can't seem to get rid of is the flex when I stand on one corner of the trailer in the rear or the front opposite corner raises up a half to three quarters of an inch.Any help would be appreciated thanks
Reply:Originally Posted by GreaslifeSo here's what I got The trailer started out as a travel trailer. I cut off the tongue and 5 feet off the back to make a 20 foot by 93inch wide trailer. The main frame of the trailer is a 6 inch C channel which is a True channel not press formed. All the cross braces are 2 x 1/4 angle iron. Has two 7500 pound axles with brakes on one axle.  The timing is a 4 x 4 by eighth inch deck square tube that the main rails sit on top of. This trailer is meant to haul a pre-runner and a couple kids quads. My problem that I can't seem to get rid of is the flex when I stand on one corner of the trailer in the rear or the front opposite corner raises up a half to three quarters of an inch.Any help would be appreciated thanks
Reply:Tractor is a 1910. I was planing on 1x expanded 10g for the finders. The quads will go between the fenders but my prerunner has too go over the top of them.
Reply:Twist like that is normal and necessary for an open frame trailer, that is trailers made from angle/channel/I-beam. It would take a torque tube to take the twist out and you can read a long post about that in the projects and pics section. It is not necessary for what you are doing tho and the flex won't hurt anything. You do have some problems with the tongue tho that could cause you some problems if not addressed. Where the bend is I don't see a bottom plate to tie the joint. Most of the stress on that joint is on the bottom so that is where the plating needs to be. Also you have no crossmember there and that is important to that type joint as well. With no tie there you can get twisting at the weld which will lead to cracking there.
Reply:I have plating on the back side along with a gusset I also have plate on the bottom that's plug welded