I believe that trailer has 225/75R15 tires on it stock. According to my calculations the radius of that tire would be 14.14".
235/80R16 has a radius of 15.4" and would give 1.26" of lift. Your tires would be 2.52" closer together and you would have 1.26" less clearance above.
235/85/R16 has a radius of 15.86" and would give 1.72" of lift. Your tires would be 3.48" closer together and you would have 1.72" less clearance above.
These are unloaded calculations. The lift dimensions will vary slightly under load but the other clearances should be good.
