Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

Is 26" X 1.75" Still 26" X 1.75"?

Notices
Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

Is 26" X 1.75" Still 26" X 1.75"?

Old 01-01-16, 06:53 PM
  #1  
Senior Member
Thread Starter
 
hollywoodeskimo's Avatar
 
Join Date: Oct 2015
Posts: 147
Likes: 0
Liked 0 Times in 0 Posts
Is 26" X 1.75" Still 26" X 1.75"?

I know. It's a silly question. But I just had a tire on my 1961 Schwinn Co-Ed disintegrate on me while I was riding. So, I went out and bought a tire that was labeled 26" X 1.75" just like the label on the tire that disintegrated. (Well, almost just like the old tire. The old tire said 26 " X 1 3/4". Remember fractions? Those were the days!) But when I tried to install the tire, it just would not fit over the rim. I tried a lot of cajoling. Nothing worked. The box the new tire came in was labeled 26" X 1.75". The tire was imprinted as 26" X 1.75". After breaking the steel cable that runs through the bead, I took the new tire and held it up against the old tire. Sure enough, the new tire was smaller. Of course a sensible, rational person would have done that first and not resorted to the siren call of the tractor tire changing spoon. But I was obviously beyond being rational. Has this happened to anyone else?

Is there something I missed besides measuring one tire against the other at the right time? Has the measurement system for tires changed? You know, like with lumber. You buy a 2 X 4 but it's really 1.5 X 3.5. Help!?
hollywoodeskimo is offline  
Old 01-01-16, 07:06 PM
  #2  
Really Old Senior Member
 
Bill Kapaun's Avatar
 
Join Date: Feb 2007
Location: Mid Willamette Valley, Orygun
Posts: 14,001

Bikes: 87 RockHopper,2008 Specialized Globe. Both upgraded to 9 speeds. 2019 Giant Explore E+3

Liked 1,359 Times in 928 Posts
Your title doesn't match what you then relate.
26X1.75" does = 26X1.75".
26X1.75" does NOT = 26X1-3/4".

There are something like 5-6 different RIM diameters that take "26 inch" tires.

Tire Sizing Systems

The size you need has a 571mm BSD. AKA 650C
A 26X DECIMAL has a 559 BSD.
(Bead Seat Diameter)

https://www.biketiresdirect.com/sear...linchwire=true

Last edited by Bill Kapaun; 01-01-16 at 07:11 PM.
Bill Kapaun is online now  
Old 01-01-16, 07:11 PM
  #3  
Senior Member
 
rmfnla's Avatar
 
Join Date: May 2005
Location: La La Land (We love it!)
Posts: 6,301

Bikes: Gilmour road, Curtlo road; both steel (of course)

Likes: 0
Liked 11 Times in 10 Posts
Plus, older Schwinns often had parts with proprietary sizing, including, I believe, tires...
__________________
Today, I believe my jurisdiction ends here...
rmfnla is offline  
Old 01-01-16, 07:30 PM
  #4  
Senior Member
Thread Starter
 
hollywoodeskimo's Avatar
 
Join Date: Oct 2015
Posts: 147
Likes: 0
Liked 0 Times in 0 Posts
I just went out and looked at the old tire and it dies have the notation (47 - 571) next to 26 X 1 3/4. So, I'm guessing that's the same 571 you're talking about. Thank you for the link to the tire sizing. What I don't understand, and it really doesn't matter now except out of curiosity, I don't know how 1.75 doesn't equal 1 3/4. What am I missing? Thank you for your help.
hollywoodeskimo is offline  
Old 01-01-16, 07:37 PM
  #5  
SE Wis
 
dedhed's Avatar
 
Join Date: Apr 2005
Location: Milwaukee, WI
Posts: 10,637

Bikes: '68 Raleigh Sprite, '02 Raleigh C500, '84 Raleigh Gran Prix, '91 Trek 400, 2013 Novara Randonee, 1990 Trek 970

Liked 3,474 Times in 2,106 Posts
[h=1]Schwinn Tire Sizes[/h]
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 notinterchangeable 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 tha
dedhed is offline  
Old 01-01-16, 07:45 PM
  #6  
Really Old Senior Member
 
Bill Kapaun's Avatar
 
Join Date: Feb 2007
Location: Mid Willamette Valley, Orygun
Posts: 14,001

Bikes: 87 RockHopper,2008 Specialized Globe. Both upgraded to 9 speeds. 2019 Giant Explore E+3

Liked 1,359 Times in 928 Posts
Originally Posted by hollywoodeskimo
I just went out and looked at the old tire and it dies have the notation (47 - 571) next to 26 X 1 3/4. So, I'm guessing that's the same 571 you're talking about. Thank you for the link to the tire sizing. What I don't understand, and it really doesn't matter now except out of curiosity, I don't know how 1.75 doesn't equal 1 3/4. What am I missing? Thank you for your help.
Which shoots a larger bullet, a .357 Magnum or a 38 Special?
Bill Kapaun is online now  
Old 01-01-16, 07:55 PM
  #7  
Senior Member
Thread Starter
 
hollywoodeskimo's Avatar
 
Join Date: Oct 2015
Posts: 147
Likes: 0
Liked 0 Times in 0 Posts
Thank you for the explanation, dedhed. I had no idea. Your explanation saves me some embarrassment in that I won't be bringing the 26 X 1.75 tire that I destroyed back to the store insisting self righteously that I want a refund. It appears it is all on me. Thanks again.
hollywoodeskimo is offline  
Old 01-01-16, 08:00 PM
  #8  
Senior Member
Thread Starter
 
hollywoodeskimo's Avatar
 
Join Date: Oct 2015
Posts: 147
Likes: 0
Liked 0 Times in 0 Posts
Couldn't tell you. I gave up on guns around 50 years ago. But I do know that in math 1.75 = 1 3/4. My mistake was thinking that math and tire sizes were fairly consistent with each other. Guess not. Live and learn.
hollywoodeskimo is offline  
Old 01-01-16, 10:00 PM
  #9  
Senior Member
 
dsbrantjr's Avatar
 
Join Date: Sep 2010
Location: Roswell, GA
Posts: 8,326

Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta

Liked 1,100 Times in 728 Posts
Here is a fairly complete explanation of tire sizing systems: Tire Sizing Systems
You won't go wrong if you go by the ISO/E.R.T.R.O. sizing, 571 in your case. Sometimes the numbers are switched and will read 571-47 rather than 47-571.

Also be aware that many of the Schwinn rims had flat (not hooked) rim sides. The flat sides will not tolerate as high pressure as hooked without the tire blowing off of the rim, so use caution not to over-inflate.
dsbrantjr is offline  
Old 01-01-16, 11:09 PM
  #10  
Senior Member
Thread Starter
 
hollywoodeskimo's Avatar
 
Join Date: Oct 2015
Posts: 147
Likes: 0
Liked 0 Times in 0 Posts
Thank you for a helpful response, dsbrantjr. I will check out the rims more closely. I must have gotten lucky finding a tire the last time I replaced a tire on this bike (probably about 15 years ago). Either that or I knew more then than I do now.

This passage from the link you provided clears it all up nicely:

[h=2]Does Point Seven Five Equal Three Quarters?[/h] Note that the inch-based designations sometimes express the width in a decimal (26 x 1.75) and sometimes as a common fraction (26 x 1 3/4). This is the most common cause of mismatches. Although these size designations are mathematically equal, they refer to different size tires, which are NOT interchangeable. It is dangerous to generalize when talking about tire sizing, but I would confidently state the following:


[h=3]Brown's Law Of Tire Sizing:[/h] If two tires are marked with sizes that are mathematically equal,
but one is expressed as a decimal and the other as a fraction,
these two tires will not be interchangeable.
hollywoodeskimo is offline  
Old 01-02-16, 09:43 AM
  #11  
Old fart
 
JohnDThompson's Avatar
 
Join Date: Nov 2004
Location: Appleton WI
Posts: 24,923

Bikes: Several, mostly not name brands.

Liked 3,532 Times in 2,001 Posts
Originally Posted by hollywoodeskimo
What I don't understand, and it really doesn't matter now except out of curiosity, I don't know how 1.75 doesn't equal 1 3/4. What am I missing? Thank you for your help.
While 1.75 does equal 1-3/4, under the old, deprecated tire size designations a decimal value for width on a nominal 26" x 1.75 tire was used to indicate a 559mm bead seat diameter tire, while a fractional width designation on a nominal 26" x 1-3/4 tire was used to indicate a 571mm bead seat diameter tire. It was a hot mess, and that's why it is much safer to use the ETRTO tire size designations instead. The ETRTO 41-571 marking on your original tire would have led you directly to suitable 571mm bead seat diameter replacements.

Last edited by JohnDThompson; 01-02-16 at 03:12 PM.
JohnDThompson is offline  
Old 01-02-16, 05:38 PM
  #12  
Senior Member
Thread Starter
 
hollywoodeskimo's Avatar
 
Join Date: Oct 2015
Posts: 147
Likes: 0
Liked 0 Times in 0 Posts
Thank you, John. I was naive. I will never look at a bicycle tire the same way again.

Last edited by hollywoodeskimo; 01-02-16 at 05:39 PM. Reason: clarity
hollywoodeskimo is offline  
Old 01-02-16, 07:50 PM
  #13  
Senior Member
 
Join Date: Dec 2005
Location: Sunny Tampa, Florida
Posts: 1,543
Liked 50 Times in 41 Posts
Originally Posted by hollywoodeskimo
But I do know that in math 1.75 = 1 3/4. My mistake was thinking that math and tire sizes were fairly consistent with each other.
You've already figured out that you aren't the first person probably not in the first million people to make this mistake.

Last edited by Ronsonic; 01-02-16 at 07:54 PM.
Ronsonic is offline  
Old 01-02-16, 10:11 PM
  #14  
Senior Member
Thread Starter
 
hollywoodeskimo's Avatar
 
Join Date: Oct 2015
Posts: 147
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Ronsonic
You've already figured out that you aren't the first person probably not in the first million people to make this mistake.
I guess you're right, ronsonic. It's still a little embarrassing. But it's a good lesson to learn, or is it re-learn, as I get back into cycling after many years. BTW, I finally did get the right sized tire and I'm back on the road. The first guy at the bike shop, a younger guy, got a little confused. One of the older guys went back in the shop and after 5 or 10 minutes came out with the right tire.
hollywoodeskimo is offline  
Old 01-02-16, 11:25 PM
  #15  
cs1
Senior Member
 
cs1's Avatar
 
Join Date: Feb 2004
Location: Clev Oh
Posts: 7,095

Bikes: Specialized, Schwinn

Liked 27 Times in 25 Posts
Originally Posted by Bill Kapaun
Which shoots a larger bullet, a .357 Magnum or a 38 Special?
lets not forget the 9mm. Somehow I don't believe that analogy is going to make it with most around here 😃

BTW, I liked it.
cs1 is offline  
Old 01-03-16, 01:02 AM
  #16  
Insane Bicycle Mechanic
 
Jeff Wills's Avatar
 
Join Date: Mar 2008
Location: other Vancouver
Posts: 9,902
Liked 784 Times in 411 Posts
Originally Posted by Ronsonic
You've already figured out that you aren't the first person probably not in the first million people to make this mistake.
As a matter of fact, the decimal-vs.-fraction error is how I ended up working in the local Schwinn bike shop. I managed to lever a 26 x 1.375" tire on a 26 x 1 3/8" rim. Being the smart kid I was I knew they were the "same". It took some big tire irons and a lot of grunting, but it went on. Of course, I pinched the tube in the process and the tire wouldn't have seated anyway. My next trip was to the local Schwinn shop, where the chief mechanic took pity on me, chopped the tire off, and explained the difference between department store "EA-3" tires and Schwinn "S-6" tires. A couple months later he offered me a job.

Nearly 40 year later, here we are... still facing the same issues.
__________________
Jeff Wills

Comcast nuked my web page. It will return soon..
Jeff Wills is online now  
Old 01-03-16, 09:53 AM
  #17  
Really Old Senior Member
 
Bill Kapaun's Avatar
 
Join Date: Feb 2007
Location: Mid Willamette Valley, Orygun
Posts: 14,001

Bikes: 87 RockHopper,2008 Specialized Globe. Both upgraded to 9 speeds. 2019 Giant Explore E+3

Liked 1,359 Times in 928 Posts
Originally Posted by cs1
lets not forget the 9mm. Somehow I don't believe that analogy is going to make it with most around here 

BTW, I liked it.
9mm is a tad smaller diameter.
I visualized many blank stares at the question though.
Bill Kapaun is online now  
Old 01-03-16, 12:19 PM
  #18  
cs1
Senior Member
 
cs1's Avatar
 
Join Date: Feb 2004
Location: Clev Oh
Posts: 7,095

Bikes: Specialized, Schwinn

Liked 27 Times in 25 Posts
Originally Posted by Bill Kapaun
9mm is a tad smaller diameter.
I visualized many blank stares at the question though.
[MENTION=78399]Bill Kapaun[/MENTION] I laughed like crazy when I read it. I just couldn't come up with a bike related one as good as yours. Considering cycling is a little left of center I assumed the blank stares also.
cs1 is offline  
Old 01-03-16, 05:10 PM
  #19  
Senior Member
 
Join Date: Dec 2005
Location: Sunny Tampa, Florida
Posts: 1,543
Liked 50 Times in 41 Posts
9mm is a tad smaller diameter.
Only by a couple thou .... Nobody'll ever know.
Ronsonic is offline  
Old 01-03-16, 05:37 PM
  #20  
SE Wis
 
dedhed's Avatar
 
Join Date: Apr 2005
Location: Milwaukee, WI
Posts: 10,637

Bikes: '68 Raleigh Sprite, '02 Raleigh C500, '84 Raleigh Gran Prix, '91 Trek 400, 2013 Novara Randonee, 1990 Trek 970

Liked 3,474 Times in 2,106 Posts
Us .44 owners wonder why you'd care about something so small.
dedhed is offline  
Old 01-03-16, 07:04 PM
  #21  
Senior Member
 
Join Date: May 2015
Location: Colorado
Posts: 1,719
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Bill Kapaun
9mm is a tad smaller diameter.
I visualized many blank stares at the question though.
That it is...
ltxi is offline  
Old 01-03-16, 07:37 PM
  #22  
Really Old Senior Member
 
Bill Kapaun's Avatar
 
Join Date: Feb 2007
Location: Mid Willamette Valley, Orygun
Posts: 14,001

Bikes: 87 RockHopper,2008 Specialized Globe. Both upgraded to 9 speeds. 2019 Giant Explore E+3

Liked 1,359 Times in 928 Posts
Originally Posted by dedhed
Us .44 owners wonder why you'd care about something so small.
And then, some wonder why you consider .44 so big?
Bill Kapaun is online now  
Old 01-05-16, 05:33 PM
  #23  
Banned.
 
Join Date: Jun 2010
Posts: 434
Likes: 0
Liked 1 Time in 1 Post
45 years ago, when I was in college in Pasadena, I needed a new tire for the used bike I had bought. An auto tire place (Milne?) had a little shack behind it with bicycle tires and tubes. It was not particularly clean and very informal:nothing on display, no choice of brands, tubes unboxed, but it was cheap. An old Black guy worked there. I bought a tire by asking for the decimal equivalent of the fractions specified. It didn't fit. When I went back, the OBG asked whether it was 1 3/4 or 1.75 (or whatever it was; I don't remember). I told him that the old one said 1 3/4 but that 1.75 is the same. He told me he didn't know much about numbers, but he did know about tires, and he knew that they weren't, and he was right.
RandomTroll is offline  
Old 01-05-16, 05:58 PM
  #24  
Senior Member
 
Join Date: Nov 2015
Posts: 87
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Bill Kapaun
Which shoots a larger bullet, a .357 Magnum or a 38 Special?
grain or diameter?
Steiner74 is offline  
Old 01-05-16, 09:59 PM
  #25  
tcs
Palmer
 
tcs's Avatar
 
Join Date: Mar 2007
Location: Parts Unknown
Posts: 8,737

Bikes: Mike Melton custom, Alex Moulton AM, Dahon Curl

Liked 1,933 Times in 1,113 Posts
Originally Posted by dedhed
For example, most "middleweight" Schwinns take 26 x 1 3/4 tires, which are hard to find...
Actually, not so much.
tcs is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Mark42
General Cycling Discussion
1
09-08-17 10:14 PM
sivertholmvik
General Cycling Discussion
4
02-28-16 03:07 PM
Turtle Speed
Bicycle Mechanics
3
07-14-14 09:51 AM
sknhgy
Bicycle Mechanics
6
08-05-13 03:27 PM
escii_35
Road Cycling
13
08-24-10 01:35 AM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Your Privacy Choices -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.