Ann, for each inch larger tire that you use, the trailer will only gain 1/2”. You will have to measure how much tire to body & top of tire to top of the fender clearance you have now, in order to see how much larger you can go. Another way would be to remove the axle
and place a spacer to your desired height increase, between the axle
and the frame, if you have a rubber torsion style axle
, or if you have leaf springs, you could do a spring over axle conversion. Have you been scraping the bumper or bottom of the trailer, necessitating the desired height increase?
Dave & Paula