Originally Posted by DieselDan
You easily find old 590 ERTO 26" tires at a good bike shop. I have access to two wholesale vendors that still stock them, and I've seen them at K-Mart. Current MTB/cruiser tries are 559 ERTO.
He needs 590's or 559's. He needs 571. (S7)
The link I provided above will get the OP the tires he needs to fit. What I was unsure about was whether he was looking for original tires for a restoration or just tires that fit so he can ride it.