I don't know where you can get the bearings, but you can buy these metal tracks for your Tiger 1 and they even come with a metal barrel, if you so choose:
http://cgi.ebay.com/METAL-TRACK-SET-...QQcmdZViewItem
They are MUCH less expensive than the other sets! [sm=thumbup.gif] They are from Stella, but I don't know if they are the same price as what you have seen before.
Jason