Friday, May 29, 2009

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.


  1. BTW, when buying tubes for these Kenda tires, I chose the *fatter 26" tube* rather than the narrower one that I use for my British-size tires (EA3) and they're working just fine.

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  3. 26 x 1 3/8" is THE tyre size to request in trendy modern bike shops if you want to cause confusion and bafflement in the assistants!

  4. Why the width of the tire comes first in ISO standard designation escapes me. It would make a lot more sense to have to tire diameter come first, so that when you sort the list (as any lengthy list needs to be sorted) all tires that fit your rim will sort to be in the same area of the list. Yes, you COULD write a specific sort program that sorts them first by diameter and second by width, its just a LOT simpler to say Sort the list!.

    Sheldon Brown's stuff on tire sizing has alweays been remarkable for its clarity, but I always make it a practice to go and review it when I am looking for tires.

    Wal-mart carries cheap tires for the Raleigh 1-3/8x26 rim/tire size, right on the shelf with all their mountain bike tires (not a good place for them, since it is bound to confuse people looking for road tires for their mountain bike). Anyway, that's where I found my last set of tires.

  5. I recently replaced the tires on my old schwinn breeze. I bought them from because I thought their prices were good and they have multiple S-5/S-6 tires. I think I went with the Cheng Shin C83 tire because it better matched the tread of the previous tire. So far, they've been good, but I only go cruising around my neighborhood a few times a week. I believe Pyramid also made a iso 597 tire that you could use.

  6. First, a disclaimer. I am not an expert on anything, just an ol' geezer who decided to resurrect his 72 Suburban 5-speed that I have not ridden in years, and decided to do all the work myself. Re tires, yes, I have the S-6 rims.

    If you have a 60-79 Chicago Schwinn with a derailleur then Bob Hufford will tell you everything you need to know
    and The serial# section also applies to 3-speeds and maybe others.

    Most common in this group were Varsity, Collegiate and Suburban. Varsity started with a 26" tire and then switched to 27". Apparently Collegiate always had 26" and Suburban always 27". More expensive models seem to have generally used 27".

    You will find lots of stuff on the internet beginning with something like, "If you have an S-6 rim then you need..." Well, maybe - and conditionally true is not absolutely true. The S-6 designation seems to describe the cross-section of the rim and has nothing to do, per se, with the diameter. It was used with 24", 26" and 27" tires. So which tire do you need?

    1) "If it ain't broke, don't fix it." If the current tires worked okay for years, then similar tires will probably continue to work. Just make sure they are absolutely the same type. Remember, that these are Schwinn tire sizes, not Raleigh or anybody else.

    2) "Trust, but verify." Remove the front wheel and measure your rim diameter. The hub may push out the tape a little but it doesn't matter. If the rim is about 22" then you need a 24x1-3/8. If the rim is just under 24" then you need 26x1-3/8. If the rim is just over 25" then you need 27x1-1/4. Again, Schwinn size, nobody else's, but you can go by the modern ISO designation. That translates 24" ~ 37-547, 26" ~ 37-597, and 27" ~ 32-630. Be careful with the 547 and 597, not 540 or 590.

    Kenda makes a 24" and 26" that will work. List $19.95, generally discounted. Many more choices with the 27", since Peugeot and others also used them. Other widths are available, but 32 mm seems to work well. I went with a puncture resistent Schwalbe, suggested 85 psi. These and most are made for a beaded rim, not a straight rim like the S-6, but seem to work okay. Sheldon Brown cautioned not to go above 75 psi. I haven't had any trouble. Good luck,..., (and I hope what I have said here is actually true).

  7. I see some shop selling Schwinn Racer parts except tires.My brother has the original tires but then he wants to buy a new set of tires.The problem,it's a bit hard to find.

  8. Schwinn makes some of the best bikes around for years. It's a pity that the parts are so hard to find. Thanks for the info on where to find some good replacements!

  9. Thank you for Schwinn tyre fact.I never seen that before.