Weird problem, trailer sway and possible 5th wheel issue?

So... I have a weird problem, when I'm driving, my trailer is going from side to side, now at first I thought it might be the wind ( about 8mph ) but I don't think it's big enough to do that, I have a Tanker btw, about 48,000+ lbs, and I didn't see the other trucks that was passing me doing that. It’s not big but it's doing it enough to be noticeable a little, now, my other suspicion is that something's wrong with my fith-wheel, reason being is I think I can see from my mirror that the trailer is a little crooked to the right, so at high speed, it tries to go further to the right and I have to correct it and try to make it go straight and follow my truck hence the side-to-side motion, I don't know what's wrong with it, maybe I backed into the trailer at an angle or something. One more thing, I got all my drive tires replaced, some of them look like retread to me, and no, I haven't call the shop yet, what do you guys think? Thanks!!

 

The trailer does have one leg that's shorter than the other but that shouldn't cause it. That's a drop and hook so I hopefully it's a trailer problem and not a truck problem...

 

Cool, the company put them on btw, why couldn't they give me new ones instead, I guess tires are expensive lol.

It's nice to know that I'm not the only one lol, still feel weird as hell though.

I never knew that, we learn something new everyday.

 

How long did that take? Did you do it at a company terminal?