Having pulled single axle...tandem axle...triaxle....tandem dual axle trailers for a living one thing I found from running different load ranges/sizes and tread patterns is braking issues. This will show up under hard braking events and especially on wet pavement....and flat spots across the tires tread caused from one brake on the end of a axle locking up first.
A trailer axle need the same size/load range/tread patterns on both ends for best results.
Normal speeds and normal braking should be no problem till you can mount proper tires on the trailer.