[Loxmyth]

The 8" Andymark tires (tires, without hubs/wheel) are used in the mobility scooter business. I was able to secure what we need with a medical supply warehouse, but I took all they had. They called the manufacturer (Cheng-Shin/Maxxis) and the manufacturer is apparently out of stock.

Finding them at a medical supply store may be more expensive, but if they have them on hand, it might be worth your trouble if you desperately need them.

Here's some search terms for the tires to save you some time:
200x50mm tires
8"x2" tire
8" Scooter tire
T021 tire
8X2″ KNOBBY TIRE
GRAY PNEUMATIC WHEELCHAIR OR SCOOTER TIRE

Good Luck!