97 International single axle dump truck and it starts shaking like something is out of round only when it's loaded. This is a 26000 GVW truck and I'm usually loaded to 32 to 33000 pounds, juice brakes. Truck is used for my farm ony, nothing comerical. I bought the truck last year and had all new tires (not recaps) and rims put on it by Raben. Rims are steel 22.5 budd's, and it seams to do it between 35 to 45 mph but goes away above or below. Rims where bought from Raben when I bought the tires and are remanufactured not brand new. Any ideas?