There was an article in FWW by Robert Vaughn (or Vaughan?) on tuning up
a bandsaw that included how to replace the tires including showing how
to form the crown....it's well worth seeing.

David Marks also had an episode of Wood Works on DIY where he went through
tuning up a bandsaw, including replacing and truing the tires.

http://www.diynetwork.com/diy/wk_tools/article/0,2037,DIY_14429_2278285,00.html

-John