Adapt-
As Daniel mentioned, I personally do not think bias ply tires are a great option for heavily loaded single axle trailers (i.e those with heavy 18-20-ish foot boats). They generally work fine on smaller trailers or for tandems that can spread the load across multiple wheels, but when supporting a heavy load tend to deform a bit during turns and often develop cupping wear on the outside corners. Are the 205's you bought radials or bias?