Tony,
Sorry to hear about your aggravation....
Read
9.00 X 16 U.S. versus British wheels and
new 9.00-16 tyres for WD split rim wheels: conclusion is that US size tyres are too small for British 16" 15-cwt rims.
You basically have two options:
- turn down the diameter of the rims on a lathe (like Wayne said)
- or increase the diameter of the tyre by shaving the tyre bead.
Because of production differences, of course some of us will find some tyres with just a little larger diameter bead, that can be fitted with plenty of soap and force.
20" British rims do not have this diameter difference, so US sized tyres fit without a problem.
Hope this helps!