Schwinn Tire Sizes, AKA 1 3/4 does not = 1.75...and more

Discussion in 'All Things Schwinn' started by rustjunkie, Sep 9, 2015.

  1. #1 Posted Sep 9, 2015

    Moderator Staff Member

    Joined:
    Jul 11, 2012
    Messages:
    11,361
    Likes Received:
    13,799
    Location:
    Monrovia, CA 91016
    Schwinn used some odd tire sizes. The most common we see are the 26 x 1 3/8" and 26 x 1 3/4".
    Fitting a tire to a rim is all about "bead diameter" which is printed on most tires.
    Below are links explaining it:

    http://www.sheldonbrown.com/tire-sizing.html

    https://www.sheldonbrown.com/rim-sizing.html

    From http://www.sheldonbrown.com/chicago-schwinns.html

    "In general, U. S.-made Schwinns take oddball Schwinn size tires, with the exception of 630 mm/27 inch, which is standard.

    Good mathematics doesn't always help you when it comes to bicycle tires. For example, most "middleweight" Schwinns take 26 x 1 3/4 tires, which are hard to find, not 26 x 1.75 as used on other brands. You might think that these are the same, but they are not.

    The 26 x 1.75 size is the normal I.S.O. 559 mm size used on most mountain bikes; the 26 x 1 3/4 (I.S.O. 571 mm) is not interchangeable with any normal tire of similar width, although its bead circumference is the same as the "650C" size used on some high performance 26" wheel bicycles.

    Designating the width with a fraction instead of a decimal usually signifies a straight-sided rim, not a hook-edge rim. The rim/tire diameter is also slightly different. Let the tire buyer beware! There are similar problems with other Schwinn tire sizes. The most common difficulty is that the Schwinn 26 x 1 3/8 (I. S.O. 597 mm) interchanges with the British 26 x 1 1/4, not the British 26 x 1 3/8 (I. S.O. 590 mm)."
     
  2. #2 Posted Sep 11, 2015

    Riding a '38 Autocycle Deluxe

    Joined:
    Sep 2, 2012
    Messages:
    7,294
    Likes Received:
    4,668
    Location:
    Central Arizona
    #2 GTs58, Sep 11, 2015
    Last edited: Sep 11, 2015
    rustjunkie likes this.
  3. #3 Posted Feb 28, 2017

    On Training Wheels

    Joined:
    Feb 27, 2017
    Messages:
    1
    Likes Received:
    0
    Location:
    Albany, Oregon
    In math 1.75 equals 1&3/4 but with bike tires there is a difference. I've always believed that an American made Schwinn bike was the best and Schwinn used tires with fractions (1&3/4 for middleweights, etc.) so Schwinn bikes are a "fraction" better. It's a gentle reminder for me.
     
  4. #4 Posted Mar 19, 2017

    'Lil Knee Scuffer

    Joined:
    Jan 12, 2015
    Messages:
    10
    Likes Received:
    1
    That reminds me......
    Should a 26 x 1.75 tired middleweight bike have a narrower rim than a heavyweight with 2.125 width tires?

    Thanks

    Pete
     
  5. #5 Posted Sep 5, 2017

    Cruisin' on my Bluebird

    Joined:
    Jul 21, 2013
    Messages:
    2,269
    Likes Received:
    1,181
    Location:
    Rochester Hills, MI
    WOW...thanks for the explanations gents, appreciate it.

    Mike
     
  6. #6 Posted Sep 5, 2017

    Look Ma, No Hands!

    Joined:
    Jul 22, 2016
    Messages:
    41
    Likes Received:
    45
    Location:
    Fort Wayne, IN, United States
    I recently had a set of BF Goodrich Silvertowns that were sized 26x1.75, fits s7 rim.
    may have been one of the first "aftermarket' s7 tires?
     
  7. #7 Posted Nov 7, 2017

    Cruisin' on my Bluebird

    Joined:
    Feb 6, 2012
    Messages:
    2,638
    Likes Received:
    1,142
    Location:
    Earth
    That isn't the hardest part, it's the axle/hub width. I guess I'll go measure my Hornet.
     
  8. #8 Posted Nov 7, 2017

    Cruisin' on my Bluebird

    Joined:
    Feb 6, 2012
    Messages:
    2,638
    Likes Received:
    1,142
    Location:
    Earth
    Are a pair of rims for a DX going to work for my Rollfast ballooner is what I'm trying to figure out? The front seems spot on but the rear may be too wide for it. Otherwise the rims are new with Kenda whiltewalls and it's a great price.
     
  9. #9 Posted Nov 7, 2017

    Cruisin' on my Bluebird

    Joined:
    Feb 6, 2012
    Messages:
    2,638
    Likes Received:
    1,142
    Location:
    Earth
    And Schwinn middleweights could use 1.95 and 2.125" dia. tires. At least the later ones I've owned from the 90s.
     
  10. #10 Posted Nov 7, 2017

    Cruisin' on my Bluebird

    Joined:
    Feb 6, 2012
    Messages:
    2,638
    Likes Received:
    1,142
    Location:
    Earth
    I have a New Departure brake hub on that Hawthorne/Rollfast wheelset and it looks like the same hub I saw on an S-2...the AXLE is the same, isn't it?

    Go ahead and move this if you wish but I don't understand this part of the Schwinn equation.
     
  11. #11 Posted Nov 7, 2017

    Moderator Staff Member

    Joined:
    Jul 11, 2012
    Messages:
    11,361
    Likes Received:
    13,799
    Location:
    Monrovia, CA 91016
  12. #12 Posted Nov 7, 2017

    Cruisin' on my Bluebird

    Joined:
    Feb 6, 2012
    Messages:
    2,638
    Likes Received:
    1,142
    Location:
    Earth
    :) Let's do it! - Tone Loc
     
    rustjunkie likes this.
  13. #13 Posted Nov 8, 2017

    Cruisin' on my Bluebird

    Joined:
    Feb 6, 2012
    Messages:
    2,638
    Likes Received:
    1,142
    Location:
    Earth
    PS DID it...In time for Christmas.
     
  14. #14 Posted Apr 1, 2018

    Look Ma, No Hands!

    Joined:
    Jun 29, 2016
    Messages:
    25
    Likes Received:
    1
    Location:
    Austin
    Wat is the diff between an original Schwinn tire and a repro? Please lmk thanks
     
  15. #15 Posted Apr 1, 2018

    I live for the CABE

    Joined:
    May 9, 2010
    Messages:
    1,273
    Likes Received:
    264
    Location:
    Sharon wi United States
    The manufacturer and the cost to the restorer. What size are you looking for. Roger