Im with noglider on this one, you'd have to discribe what type of wheels?
You have to remember that ordinary bike wheels on a trailer are not designed to take heavy loads.

If it is trailer wheels your looking for, you may want to invest in a pair of Skyways Utility Wheels.



SKYWAY'S Utility Wheels page.
http://www.skywaywheels.com/products_005.htm

Regards
Tom