Originally Posted by
noglider
650c is uncommon and seems to be racing oriented. I've only seen very narrow tires in that size.
Actually, there are two different and non-interchangeable 650C (bead seat diameter 571mm) tire sizes: the time trial/small frame road bike 650C tires, that are, oh, round about 1" wide, and the original semi-balloon 650C size which we call in America 26x 1 3/4.
650a is the same as wheels that came on English 3-speeds and many other bikes. Rim and tire selection isn't very good.
Here are the 650A (a.k.a. 26 x 1 3/8 a.k.a. EA3 a.k.a. ISO590) tires I found available when I looked last, around 6 months ago:
Bell Sports Streetster (folding)
Chengshin C638
Continental City Ride
Hutchinson Junior
Innova Cloud Nine
IRC Super Gold
IRC Super Seed
IRC City POPS
Kenda gumwall
Kenda Cross (knobby)
Kenda K40 Street
Michelin World Tour
Nutrak Traditional
Nu-teck (airless)
Panaracer Col de Vie
Panaracer Passhunter (light knobby)
Panaracer ST Daily Commuting
Pyramid gumwall
Pyramid Sunlite Hybrid Nimbus
Raleigh Record
Rubena Flash V66
Schwalbe Delta Cruiser (available in cream color)
Schwalbe Marathon
Schwalbe Marathon Plus
Schwalbe Speedway Pro (knobby)
Specialized TriSport
Vittoria Randonneur
Vredestein Perfect Tour
Vredestein Dynamic Tour
Vredestein Classic
I've never had a problem finding rims for ISO590mm.