Some time ago on here there was trailer tire discussion. What most were doing with great success was upgrading to a 16" wheel/tire package. If that's not an option some were recommending Maxxis(spelling) tire (load range 'E') at about $160 each. If that thread is archieved it is worth a read IMO. IIRC HemiJoel was a wealth of good info in that post. Either way, let us know what you came up with.