I'm looking for a supplier of small trundle bed wheels. The wheels
that came with the trundle bed that I own keep breaking due to
frequent pulling out of the bed -- and because the wheels are made of
cheap plastic. I've looked everywhere I know of on the net to find a 
supplier. The wheels need to be small enough to allow me to push the
trundle back under the top bed. Hardware stores have replacement
wheels butthey end up being too tall and, when I mount the wheels on
the bedframe, I can't push
the trundle bed back under the top bed.  The original manufacturer of
the bed (Workbench) is no longer in business and so they can't tell me
who the manufacturer of the wheel is.  The wheel needs to come mounted
so that I can screw the wheel into the trundle bed frame. I think the
wheels measure about half an inch in diameter. Normally wheels like
this are mounted on swivels. I need mounts that just allow back
andforth movement. Not 360 degree movement.