My '71 CT1 is in need of new tires (front basically disintegrated today) and there seems to be limited sources and compatible models.  3.25-18 on the front seems particularly rare.  3.50-18 on the rear.

Best source of compatible tires for these early 70's bikes?  I'm hearing SHINKO 241's but are there others and where do you get them?

Thank you!
 

I put a Duro HF307 3.00 x 18 front tire on a '69 CT1 I resurrected.  Look it up on Amazon. It was slightly narrower than the stock tire. It seemed to perform pretty well. Good luck!

 

There's a thread on tires here: www.yamaha-enduros.com/index.php/forums/...6-master-tire-thread

Shinko are fine for me but I do hear a lot of talk about the heidenau vintage dual sport tires. Not sure if it’s the K41 or K67s. They look nice.
 

I think the Shinko 241's are so popular because they're very reasonably priced, readily available, and they look very similar to the old Yokohama Trail Sport tires. I put 3.0 x 18 front and 3.5 x 18 rear on my 1971 CT-1. When I removed the old front tire, it had a long deep crack in the sidewall. I think if I'd taken it up to speed with those old tires they could have disintegrated. I'm just riding on the road and wanted an original look. For trail use you might want to explore some of the other options, though I think these might be better than the originals. They're more aggressive on the edge, and have more splits in the tread blocks 

 I got mine from Revzilla, and they have other brands as well. Seem to have a good stock and good prices.

I took a slightly different (non traditional) approach for the tires on my CT3:

- Front Shinko 244 series with a wider width of 3.5"

- Rear Dunlop D605 at a width of 4.1"

You can see pics on page 3 of this post:

Pics of my tires installed: