Hi,
I would recommend that you look at this web site for tires and rims, for your trailer if you want to go to 16" size. If you do not see what you want than contact them for their recommendations.
https://www.southwestwheel.com/store...-assembly.aspx
This site was recommended to me from another member on the Turbo Diesel Register forum which I am a member also.
I am looking to upgrade my tires this spring on my trailer, which is a 318SAB Cougar. I will be dealing with them since I want Michelins XB ribs for my trailer.
Jim W.