Might just be the angle of the pictures, but are you allowing enough clearance between the spring support post and the hanger as the spring length increases when loaded?Once this is done the main frame is then flipped over final weld's finished and the wheels laid up to get the axle lengths. they are set up welded and bolted into the springs, wheels fitted and Fender's mocked up. the side's are then welded on, These then take the trailer out to 2.4m which is the inside total width, The covered section is 2m tall inside x 2.4 wide x 4m long it then will tapper in to 2m wide at the front and 1.5m high this will make it less of a brick to pull through the wind.
I have put a bench in the front with storage bins under it that slide out like drawers, the tyres will go under them on the floor. the floor will have garage carpet on it. The lower part of the outside panels has alloy checker plate for a bit of stone protection and visual effect.
I get asked that question all the time.You will need to figure out a price for one of those because as soon as you take it to the track you're going to get asked to make one for somebody. I am talking about the trailer. Well done!