Christine;
     I bought four in Whitehorse, Canada a couple of years ago. It was a
national chain in Canada, Tire Depot or Barn or something like that. West
Coast Canadian tire shops seemed a lot more knowledgeable than our south-
of-the-border types.  You might want to call Canadian Tire or another shop
right across the border in BC.  I bet they have XCA's or another suitable
replacement in stock.
     Good luck on your search.

     John
     87 Westy/soon to be Subaru SVX powered