Hello: If you need a brand or size that's not available here in North America you might try WheelHouse Tyres of Birmingham in the UK. Their website is
http://www.wheelhousetyres.co.uk. They had Continental KKS10 tires in 2.25 X 16 that I needed in stock. Another possibility is Central Wheel Components, also in Birmingham, at
http://www.central-wheel.co.uk. I was able to locate a pair of Pirelli ML12 tires in Germany but couldn't find a shipper who could send them to the States. Central was able to accept the shipment, repackage it and then send it to me. Hope this helps.