It is a standard size, and . . .
You can get new wheels with the tires already mounted at West Marine or Boat/US. I would go with the galvanized wheels versus the painted. They are the 5-bolt pattern, which is an automotive standard.The Catalina 22 trailer of years gone by had 15" wheels, but 14" wheels should work equally well. I think the 14" wheel is about the largest wheel you will find in stock at the local marine retailers.The key thing is to make sure the tires are rated for the load. You should look for tires with a load rating of 1750 lbs (each) to accomodate your trailer load rating of 3500 lbs (most C22 trailers are 3500 lb GVWR trailers).I hope this helps,Regards,Ted