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


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rustjunkie

Moderator
Staff member
Jul 11, 2012
11,696
14,664
Monrovia, CA 91016
www.rustjunkies.com
#1
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)."
 

Jerry Blais

On Training Wheels
Feb 27, 2017
1
0
66
Albany, Oregon
#3
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.
 

64 Pete

'Lil Knee Scuffer
Jan 12, 2015
10
1
#4
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
 

farkasthegoalie

Look Ma, No Hands!
Jul 22, 2016
45
53
42
Fort Wayne, IN, United States
#6
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?
 

Saving Tempest

Cruisin' on my Bluebird
Feb 6, 2012
2,936
1,306
52
64.7511° N, 147.3494° W
#8
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.
 

Saving Tempest

Cruisin' on my Bluebird
Feb 6, 2012
2,936
1,306
52
64.7511° N, 147.3494° W
#10
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.
 

Saving Tempest

Cruisin' on my Bluebird
Feb 6, 2012
2,936
1,306
52
64.7511° N, 147.3494° W
#18
so is a Schwinn 26 x 1.75 tire 571 ETRTO?
I've used all manner of 1.75-1.95" from the bike shop or dept. stores that sell tires and tubes. I'm not sure I've ever seen the rims mentioned.

You aren't dealing with this situation for at least the last 45 years anyway, that I can recall.
 

Saving Tempest

Cruisin' on my Bluebird
Feb 6, 2012
2,936
1,306
52
64.7511° N, 147.3494° W
#19
My mom would put Schwinns and Huffys together for me from a bicycle junkyard and I used to be able to deal with changing tires and tubes much better before I injured my hand.
 

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