MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
You could try to hold the wheels on a long nail through their holes. Then press it against a flat piece of sand paper on a table top. Move the nail with the wheels in a diagonal fashion so that you make them turn but at the same time also achieve som sanding of the wheels. This should make them round which makes them turn easier.