The Onyx bass wheel has sturdy construction and nice give to the tire. This one has a 1/2" shaft. It's in good shape, with plenty of tread left on the tire.
I really like this wheel, but it tends to turn in my endpin socket since I'm using a carbon fiber endpin...no set screw to hold onto the flats on the wheel's shaft.
Here's a link: http://www.lemurmusic.com/ONYX--Upri...uctinfo/A1154/
Asking $50 shipped.