If the wheel lugs were put on with an
Impact Wrench, you may have to take them off with an
Impact Wrench. Last fall I bought a 1/2 inch drive impact wrench from Sears (580 Ft.Lbs Max Torque)... JUST to remove my trailer wheels which have been on the trailer for a decade.
With the liberal application of "PB Blaster Penetrating" (From Benny's) over a few days, and the impact wrench, the lugs
finally came off. When the wheels go back on I will use "Permatex Anti Seize" compound (From Benny's) on the lug bolt threads and shoulders. There are no "studs & lugnuts" on my EZ Loader trailer.
BTW: 580 Ft.Lbs torque would be the MINIMUM size impact wrench I would buy for this purpose.

NB
SEARS:
http://www.sears.com/shc/s/p_10153_1...3&blockType=G3