Ride quality of ISO tank chassis trailers

I pull spring ride, spread axle, gooseneck chassis trailers that are made to carry a single portable ISO tank container all the time (probably 80% of my work). I was wondering if anyone else on here has any experience or knowledge about these trailers, because to me, the ride quality of these things are absolutely terrible! It constantly has a strong vibration and shake no matter what speed and it just feels so heavy... like it weighs 1,000,000 lbs or something crazy. My fuel mileage drops down to about 4.6 mpg also. Yikes! Does anyone else have these issues or is it just my truck?

 

Yep, sure is. 2015 VNL 630... Spring ride front axle, Merritor MT40 rear axles on Volvo air ride. Truck has new shocks all the way around and 10 brand new tires along with Centramatic wheel balancers on all corners. I’m beginning to think it’s the truck and I have another post about it on the Volvo forum

 

Yeah I like to compare it to pulling a big ### open parachute down the interstate at 75 mph LOL It does catch every single bit of wind and engine stays under 100% load pretty much the whole time. I can do a lot better if I stay around 60 mph instead of 75 but I just can’t stand going that slow!

I know they’re not long skinny Cadillac’s or nothing, but I know they’re not supposed to be this bad. I’ve pulled these for years... but they’ve all been this one type & one brand. They’re not only just a spread axle-spring ride, but the leaf spring hangers are connected by a beam; front to back. The main reason for this post is to figure out if the problem is with these particular chassis trailers or my truck itself. I have more info about specifics in my other post in the Volvo forum. I’ve never pulled a chassis with tandem spring-ride or any combo of air ride, so I was hoping someone has so I could somewhat compare the differences.