Schwinn Tire Sizing

Left: Original Schwinn S-5 Right: Kenda Replacement

A commenter recently asked about where to find tires to fit a Schwinn Racer. This is a common enough question, so I thought I'd do a post about it. I should point out that I don't really know anything about tire sizes on other models of Schwinn, just the 3-speeds that supposedly take a 26 x 1 3/8" tire.

The thing is, a 26 x 1 3/8" English-size tire (or tyre, if you will) is not the same as a Schwinn-size 26 x 1 3/8" tire. I know, I know. Schwinn had a different rim/tire sizing system where rims were sized S-5, S-6, S-7 and so on. My 1961 Schwinn Racer, and other Schwinn three-speeds of similar vintage, came with either an S-5 or S-6 rim, which are the same size and will take the same tire/tube (the shape of the rim is slightly different, but does not affect the size).

The only tires that I could find on the market today in this size are made by Kenda, and they're not at all expensive. Harris Cyclery sells them online here. By the way, the I.S.O. (International Organization for Standarization) number for these is 37-597, which may help if you can get your local bike shop to order them for you. Cosmetically, they're a good match for the original tires (see above).

Clear as mud? For more on Schwinn tire sizing, see a lively discussion here. And, of course, Sheldon Brown weighed in on the topic here. Anyone with other (better) info should post it in the comments below. I just hope Kenda keeps making those tires.