mxracer78...I had the same problem with my 27HFS. FR upgraded my axles, too. I haven't towed it loaded yet but it doesn't rub empty. It sets at least 1" higher unloaded than before but it's not the vertical movement that causes the contact. It has to be the side roll. The stiffer springs should make a difference but I may install shocks, too, to further dampen that roll. The original axles were probably 3500# like mine. Make sure the new ones are heavier. The new models come with 4400# and that's what they put on mine. The rating is stamped on the center of the axle.
dunnnc...they are leaf spring mounted.